Kobe Bryant killed in a helicopter crash

flybucky · Thu Jan 30, 2020 1:33 am

Aesma wrote:
Basketball is a popular sport around the world, but a major sport only in the US. Most people around the world had never heard of Kobe Bryant before his death (and I'm sure the accident didn't make the news everywhere either).

Let's look at some analytics instead of personal opinions with small and biased sample sizes.

I compared Google Trends analytics between Kobe Bryant and Lionel Messi. I used the year 2010 since that was when both were still in their primes. Take a look at the Interest by Region graphs for each. Certainly Messi has more countries since football/soccer is the more popular global sport. But Kobe has most of the countries in Europe, Asia, South America. So he does have a diverse global fanbase.

Lionel Interest by Region

Kobe Interest by Region

And if you compare them head to head, you can see that their overall popularity is about the same.

tenHangar · Thu Jan 30, 2020 1:36 am

Audio from home security cam:

https://www.thedailybeast.com/kobe-brya ... orbell-cam

tenHangar · Thu Jan 30, 2020 1:58 am

Maybe not "spatial disorientation" . Could it have been a deliberate abort/u-turn to get below the cloud cover and go back the way he came?

GalaxyFlyer · Thu Jan 30, 2020 2:01 am

tenHangar wrote:
Maybe not "spatial disorientation" . Could it have been a deliberate abort/u-turn to get below the cloud cover and go back the way he came?

Which was disorienting and led to LOC-I.

trnswrld · Thu Jan 30, 2020 2:05 am

Wow that audio is interesting (and sad) to listen to. What I find interesting is it appears to move very slowly overhead or even stationary, Then starts to move away(possibly quickly), then just crashes. I'm no investigator, but it sounds like a perfectly functioning helicopter pretty much right up to the end.

GalaxyFlyer · Thu Jan 30, 2020 2:08 am

This from an experienced helo and powered lift pilot at PPW

Hovering a helicopter in IMC conditions without some type of coupled approach/hover, or at the very least hover symbology, capability is an absolute guarantee of an accident. Even with such systems a successful outcome is far from guaranteed. Probably the largest area of research in the military helo community over the past twenty years of so is developing methods and systems to allow helos to land in "Degraded Visual Environments", aka brownouts, dustouts, or whiteouts. This is the result of the alarming number of helicopters crashing in the insane brownout conditions we've encountered in the Middle East. It's not uncommon to completely brownout from 100 feet AGL or higher all the way to touchdown. While it may seem like I'm comparing apples to oranges the challenges the IIMC pilot would be facing are not just the same but I'd say even more dynamic. Army can provide expertise here cuz I've never flown a 76 but I do know that most helo APs I've seen don't have an auto hover feature and will actually disengage around 50 knots or so. The exceptions being helos specifically kitted out for SAR missions.

All of this begs the question, "what would I have done?" Well first I would've hoped that I would've identified the unsavory weather with enough time to reverse course and remain VMC. However, if I knew a IMC penetration was imminent or I had already punched in, I would've immediately started a max performance level attitude climb while simultaneously slowing to "bucket speed". If I were ahead of the game I would already have slowed down anticipating the possible need for maximum energy. Absent of any synthetic vision system or HTAWS or digmap with terrain highlighted, I would've maintained that straight ahead climb until I reached at least the MEF for the region or punched out of the fog. This obviously highlights having some kind of plan before this so that you know what kind of altitude would keep you safe. The only way I would've turned is if I had a system showing me high terrain in front or me thereby necessitating a turn. Any unnecessary turn would only raise the risk of inducing vertigo at this point, especially for a pilot that isn't comfortable in IMC. Once either on top or at a safe altitude and level would I then declare an emergency and start playing with other systems. Although my pure FW flying isn't as grand as most of those on here I'm guessing the same type of technique would be used by most of you.

In this accident I believe the pilot didn't simply suck it up, climb, and work an IFR clearance because he was 1) not proficient in IMC, and 2) completely unprepared for the IIMC event at that moment. His desire to maintain VMC was paramount and evident in the turn to the left, which I believe increased in bank angle as he attempted to stay visual. Once IMC it put him in an attitude that was very susceptible to inducing vertigo/SD. It also produced an overbanked attitude where his only recourse is to slow down rapidly or level the helo, your resultant lift vector gets large very quickly here in the direction you don't want it to be pointing. His reaction to seeing the VVI pointed scarily negative was probably to pull more collective which in this situation only lead to increasing that resultant vector and increasing his rate of descent and airspeed until impact.

Gtep · Thu Jan 30, 2020 2:46 am

GalaxyFlyer wrote:
This from an experienced helo and powered lift pilot at PPW

Hovering a helicopter in IMC conditions without some type of coupled approach/hover, or at the very least hover symbology, capability is an absolute guarantee of an accident. Even with such systems a successful outcome is far from guaranteed. Probably the largest area of research in the military helo community over the past twenty years of so is developing methods and systems to allow helos to land in "Degraded Visual Environments", aka brownouts, dustouts, or whiteouts. This is the result of the alarming number of helicopters crashing in the insane brownout conditions we've encountered in the Middle East. It's not uncommon to completely brownout from 100 feet AGL or higher all the way to touchdown. While it may seem like I'm comparing apples to oranges the challenges the IIMC pilot would be facing are not just the same but I'd say even more dynamic. Army can provide expertise here cuz I've never flown a 76 but I do know that most helo APs I've seen don't have an auto hover feature and will actually disengage around 50 knots or so. The exceptions being helos specifically kitted out for SAR missions.

All of this begs the question, "what would I have done?" Well first I would've hoped that I would've identified the unsavory weather with enough time to reverse course and remain VMC. However, if I knew a IMC penetration was imminent or I had already punched in, I would've immediately started a max performance level attitude climb while simultaneously slowing to "bucket speed". If I were ahead of the game I would already have slowed down anticipating the possible need for maximum energy. Absent of any synthetic vision system or HTAWS or digmap with terrain highlighted, I would've maintained that straight ahead climb until I reached at least the MEF for the region or punched out of the fog. This obviously highlights having some kind of plan before this so that you know what kind of altitude would keep you safe. The only way I would've turned is if I had a system showing me high terrain in front or me thereby necessitating a turn. Any unnecessary turn would only raise the risk of inducing vertigo at this point, especially for a pilot that isn't comfortable in IMC. Once either on top or at a safe altitude and level would I then declare an emergency and start playing with other systems. Although my pure FW flying isn't as grand as most of those on here I'm guessing the same type of technique would be used by most of you.

In this accident I believe the pilot didn't simply suck it up, climb, and work an IFR clearance because he was 1) not proficient in IMC, and 2) completely unprepared for the IIMC event at that moment. His desire to maintain VMC was paramount and evident in the turn to the left, which I believe increased in bank angle as he attempted to stay visual. Once IMC it put him in an attitude that was very susceptible to inducing vertigo/SD. It also produced an overbanked attitude where his only recourse is to slow down rapidly or level the helo, your resultant lift vector gets large very quickly here in the direction you don't want it to be pointing. His reaction to seeing the VVI pointed scarily negative was probably to pull more collective which in this situation only lead to increasing that resultant vector and increasing his rate of descent and airspeed until impact.

Interesting read. Now the pilot was running Foreflight on his IPad. I thought Foreflight was capable of synthetic vision. Also, Foreflight will give you your GPS altitude, obviously I wouldn’t bet my life on it, but it would give you a rough idea? Forgive me, I haven’t really fooled around with this product.

IADFCO · Thu Jan 30, 2020 3:26 am

Thanks flybucky for the updated charts. I'm intrigued especially by what happens between t=-9.5 sec and t=-8.7 sec. In that 0.8 sec the vertical speed goes from about -1700 ft/min to -3500 ft/min (all figures are approximate because I read them off the chart, and in fact, from the earlier version posted at around page 5 or 6). This corresponds to an acceleration of about -11 m/sec^2 or -1.1g. In the same 0.8 sec the speed goes from 124 to 139 kts, corresponding to an acceleration of about 8.5 m/sec^2 or 0.9g. This seems consistent with a large sudden application of forward longitudinal cyclic, or, which is the same, to a large and sudden "nose down" motion of the rotor disk.

If you look at previous S-76 accidents (you can find a list on Wikipedia), the case of the Copterline Flight 103 is especially interesting. There, a runaway swashplate actuator (one of the orifices of the servovalve got suddenly clogged by a small metal particle) caused a sudden nose up motion of the swashplate, which remained stuck in that nose up position and caused an uncommanded nose up longitudinal stick input, which generated almost 1.8 g, and ultimately caused loss of control and crash of the aircraft.

I'm not implying that a runaway swashplate actuator is involved in this case too, but I think that we should all keep an open mind on mechanical failure as a possible contributing cause to the accident. I wouldn't be surprised if the NTSB investigators looked at swashplate and the overall pitch control chain with particular attention, especially given the Copterline precedent.

PS I'd appreciate if someone repeated the calculations independently.

TYWoolman · Thu Jan 30, 2020 3:34 am

aerosreenivas wrote:
The death of one of the greatest Basket Ball Player in the world, Kobe Bryant, this Sunday, due to helicopter crash has left everyone saddened. As the report says, the helicopter flew when the weather was very bad.

My question is Could it have been avoided had one of the victims strongly objected to flying in the very bad weather?

As a fan of this great player after Michael Jordan, I feel that he has 'Died Pretty Soon'. He had lots of things to be fulfilled, both for him personally and for his family.

Please Note: This is taken from the Topic of mine that was created in the Non-Aviation Forum and was shifted locked by the moderators.

Request all the members to share their views on this thought.

Cheers!

To some extent the sad irony here is Kobe Bryant's devotion to his daughter's and friend's basketball passions is in full display by persevering through any weather to get to the game. But in pure speculation here: Who knows what skepticism Kobe expressed to the pilot, but maybe the pilot reassuring it would be fine. Even mid-flight, perhaps Kobe agreed to cancel the flight and the pilot was turning back. The situation at the time was Aviate and Navigate. Communicating intentions to ATC to turn around would not be high on the list. I believe Kobe knew the flight should be cancelled and did act on that premise. However, the sickening rest is history. RIP.

GalaxyFlyer · Thu Jan 30, 2020 3:42 am

Gtep wrote:
GalaxyFlyer wrote:
This from an experienced helo and powered lift pilot at PPW

Hovering a helicopter in IMC conditions without some type of coupled approach/hover, or at the very least hover symbology, capability is an absolute guarantee of an accident. Even with such systems a successful outcome is far from guaranteed. Probably the largest area of research in the military helo community over the past twenty years of so is developing methods and systems to allow helos to land in "Degraded Visual Environments", aka brownouts, dustouts, or whiteouts. This is the result of the alarming number of helicopters crashing in the insane brownout conditions we've encountered in the Middle East. It's not uncommon to completely brownout from 100 feet AGL or higher all the way to touchdown. While it may seem like I'm comparing apples to oranges the challenges the IIMC pilot would be facing are not just the same but I'd say even more dynamic. Army can provide expertise here cuz I've never flown a 76 but I do know that most helo APs I've seen don't have an auto hover feature and will actually disengage around 50 knots or so. The exceptions being helos specifically kitted out for SAR missions.

All of this begs the question, "what would I have done?" Well first I would've hoped that I would've identified the unsavory weather with enough time to reverse course and remain VMC. However, if I knew a IMC penetration was imminent or I had already punched in, I would've immediately started a max performance level attitude climb while simultaneously slowing to "bucket speed". If I were ahead of the game I would already have slowed down anticipating the possible need for maximum energy. Absent of any synthetic vision system or HTAWS or digmap with terrain highlighted, I would've maintained that straight ahead climb until I reached at least the MEF for the region or punched out of the fog. This obviously highlights having some kind of plan before this so that you know what kind of altitude would keep you safe. The only way I would've turned is if I had a system showing me high terrain in front or me thereby necessitating a turn. Any unnecessary turn would only raise the risk of inducing vertigo at this point, especially for a pilot that isn't comfortable in IMC. Once either on top or at a safe altitude and level would I then declare an emergency and start playing with other systems. Although my pure FW flying isn't as grand as most of those on here I'm guessing the same type of technique would be used by most of you.

In this accident I believe the pilot didn't simply suck it up, climb, and work an IFR clearance because he was 1) not proficient in IMC, and 2) completely unprepared for the IIMC event at that moment. His desire to maintain VMC was paramount and evident in the turn to the left, which I believe increased in bank angle as he attempted to stay visual. Once IMC it put him in an attitude that was very susceptible to inducing vertigo/SD. It also produced an overbanked attitude where his only recourse is to slow down rapidly or level the helo, your resultant lift vector gets large very quickly here in the direction you don't want it to be pointing. His reaction to seeing the VVI pointed scarily negative was probably to pull more collective which in this situation only lead to increasing that resultant vector and increasing his rate of descent and airspeed until impact.

Interesting read. Now the pilot was running Foreflight on his IPad. I thought Foreflight was capable of synthetic vision. Also, Foreflight will give you your GPS altitude, obviously I wouldn’t bet my life on it, but it would give you a rough idea? Forgive me, I haven’t really fooled around with this product.

Amateurs all want to play with various new electronic toys. Aircraft installations all have to engineered, tested, approved by a regulator unless one wants to be a test pilot and passengers become guinea pigs as part of your test. SVS, TAWS, are great tools, using an iPad in a non-approved manner is more likely to cause an accident. SVS works fine, if it has the required number of satellites, but there’s a reason the regulators do not allow lower minimums by using SVS; and why TAWS and SVS cones with a warning to the effect: NOT TO USED FOR NAVIGATION OR TERRAIN AVOIDANCE.

GF

GalaxyFlyer · Thu Jan 30, 2020 3:44 am

TYWoolman wrote:
aerosreenivas wrote:
The death of one of the greatest Basket Ball Player in the world, Kobe Bryant, this Sunday, due to helicopter crash has left everyone saddened. As the report says, the helicopter flew when the weather was very bad.

My question is Could it have been avoided had one of the victims strongly objected to flying in the very bad weather?

As a fan of this great player after Michael Jordan, I feel that he has 'Died Pretty Soon'. He had lots of things to be fulfilled, both for him personally and for his family.

Please Note: This is taken from the Topic of mine that was created in the Non-Aviation Forum and was shifted locked by the moderators.

Request all the members to share their views on this thought.

Cheers!

To some extent the sad irony here is Kobe Bryant's devotion to his daughter's and friend's basketball passions is in full display by persevering through any weather to get to the game. But in pure speculation here: Who knows what skepticism Kobe expressed to the pilot, but maybe the pilot reassuring it would be fine. Even mid-flight, perhaps Kobe agreed to cancel the flight and the pilot was turning back. The situation at the time was Aviate and Navigate. Communicating intentions to ATC to turn around would not be high on the list. I believe Kobe knew the flight should be cancelled and did act on that premise. However, the sickening rest is history. RIP.

There’s NO way to know Bryant wanted to change the flight or cancel it. Sentiment might be nice, but it doesn’t fit in the real world.

GF

TYWoolman · Thu Jan 30, 2020 3:55 am

GalaxyFlyer wrote:
TYWoolman wrote:
aerosreenivas wrote:
The death of one of the greatest Basket Ball Player in the world, Kobe Bryant, this Sunday, due to helicopter crash has left everyone saddened. As the report says, the helicopter flew when the weather was very bad.

My question is Could it have been avoided had one of the victims strongly objected to flying in the very bad weather?

As a fan of this great player after Michael Jordan, I feel that he has 'Died Pretty Soon'. He had lots of things to be fulfilled, both for him personally and for his family.

Please Note: This is taken from the Topic of mine that was created in the Non-Aviation Forum and was shifted locked by the moderators.

Request all the members to share their views on this thought.

Cheers!

To some extent the sad irony here is Kobe Bryant's devotion to his daughter's and friend's basketball passions is in full display by persevering through any weather to get to the game. But in pure speculation here: Who knows what skepticism Kobe expressed to the pilot, but maybe the pilot reassuring it would be fine. Even mid-flight, perhaps Kobe agreed to cancel the flight and the pilot was turning back. The situation at the time was Aviate and Navigate. Communicating intentions to ATC to turn around would not be high on the list. I believe Kobe knew the flight should be cancelled and did act on that premise. However, the sickening rest is history. RIP.

There’s NO way to know Bryant wanted to change the flight or cancel it. Sentiment might be nice, but it doesn’t fit in the real world.

GF

Of course there is no way to know this. But I like keeping this in as positive light as possible since it was the last seconds of his inspirational life as was the other souls on board who shared in his passion. The myriad positions on this forum questioning in disbelief the logic of flight in this weather is a form of sentiment favoring that narrative (and rightfully so), but on flip-side, I like to think all of them in that copter agreed at one point or another: this game will have to wait!

UWS · Thu Jan 30, 2020 4:16 am

I keep wondering why they did not just land at the Van Nuys airport and get a car to TO. That would have taken an hour or so (arrival time 1030), which is only 20 minutes more than flying to Camarillo and then to TO.

Pride and getthereitis won out.

dwillens · Thu Jan 30, 2020 5:21 am

Interesting read. Now the pilot was running Foreflight on his IPad. I thought Foreflight was capable of synthetic vision. Also, Foreflight will give you your GPS altitude, obviously I wouldn’t bet my life on it, but it would give you a rough idea? Forgive me, I haven’t really fooled around with this product.

I use Foreflight on all flights (fixed wing) on an 11" iPad. Whether he was actually using it at the time of the accident and whether it was recording data is a question that I am eager to see answered (if possible). You cannot get location data from an iPad without the cell radio chip (which has GPS built-in) or some sort of wi-fi connection either through ADS-B on the aircraft or an external GPS (could be a phone, could be a Stratus or other ADS-B receiver or external GPS). Foreflight does have synthetic vision but it does not show full attitude information unless it is connected to a Stratus or other external device which provides that information. I highly doubt that helicopter was equipped in a way that would have provided the necessary attitude information to Foreflight on its own, it would have needed something else. So if Foreflight was being fed GPS data only, the synthetic vision would show a 3d terrain view but would not show attitude information to the extent necessary to actually fly the aircraft (only would show speed, heading and altitude, not pitch or bank information).

Another thing to keep in mind is that if he had the iPad on his lap and not mounted somewhere in the aircraft, he would most likely have to look down out of his normal instrument scan to see it and that could add to any disorientation that he might have been experiencing.

MrBretz · Thu Jan 30, 2020 6:01 am

Arriving in a car, even if a limo, is not as dramatic as arriving by helicopter, don't you think?

RightRudder · Thu Jan 30, 2020 6:23 am

werdywerd wrote:
Very Detailed Eyewitness account of the accident

https://youtu.be/28QYy8lrww8

Great eyewitness account. It reinforces my speculation.. There is a solar farm just over the hill on the west side of where the accident occurred. I believe that there maybe power lines connected to the solar substation. Yet regardless of whether the lines are underground or above ground, there are higher than normal telephone lines all around that area. Especially at Las Virgenes Road... The eyewitness points out on the video a lot of details. The pilot hovering over him was at approx.150 feet. It was as if he was lost. The engine sound was normal and then went silent. It was not the other way around. The engine sound did not quit after the impact explosion, but before. The pilot had already lost controlled flight. Whether if the blades caught at 150 ft. AGL, or to 1,500+ ft.

aerosreenivas · Thu Jan 30, 2020 7:27 am

Aesma wrote:
Basketball is a popular sport around the world, but a major sport only in the US. Most people around the world had never heard of Kobe Bryant before his death (and I'm sure the accident didn't make the news everywhere either). Just saying.

Basketball has been a followed sport around the world, including India, my home country for many years. Many of their nationals as well have also represented one of the NBA clubs. For example: Yao Ming of China played for Houston Rockets, Dirk Nowitzki for Dallas Mavericks and many more.

Even in India as well, many schools offer basketball coaching and participate in many inter-school basketball competitions.

Now how is this possible?

Because many of them grew up watching great NBA players like Kobe Bryant, Michael Jordan, Karl Malone, Scotty Pippen, John Stockton and many others.

So, Basketball has been popular in the past and will also be popular in the future as well around the world. Many of them get inspired by people like Kobe Bryant.

TYWoolman · Thu Jan 30, 2020 9:48 am

RightRudder wrote:
werdywerd wrote:
Very Detailed Eyewitness account of the accident

https://youtu.be/28QYy8lrww8

The engine sound was normal and then went stilent. It was not the other way around. The engine sound did not quit after the impact explosion, but before. The pilot had already lost controlled flight.

I thought the silence of noise before actual impact was a speed of sound characteristic. The silence we hear is when actual impact occurs, then impact sound travels to ears (?)

zeke · Thu Jan 30, 2020 2:00 pm

flybucky wrote:
Here is an updated granular FR24 graph, which has Adjusted Altitude now. The ADS-B Altitude is Pressure Altitude. The Van Nuys METAR at 9:51am PST was A3016. Using a Pressure Altitude calculator, that comes out to 220 ft that needs to be added to the Pressure Altitude.

This makes more sense and matches all NTSB facts. They said the helicopter climbed to 2300 ft at the end, and now the max Adjusted Altitude is 2345 ft. Also, before adjusting, there were points where it seems the heli was less than 100 ft above Hwy 101, which did not seem realistic. Now, the lowest points above 101 would be at least 300 ft.

Also note that the last ADS-B point (9:45:33.7 am, 1570 ft adj alt, -4864 fpm, 161 kts, 91°, ) is not when the heli crashed. From the Ring video, it actually crashed ~6.8s later at 9:45:40.5 am, 1085 ft. That gives an approximate vspeed of (1570-1085)/6.8*60 = -4279 fpm over those last 6.8s. A pretty reasonable value.

Your numbers are out a bit, both BUR and VNY controllers gave 30.19 as the altimeter to 2EX over the radio, that is what they would have been using. I also grabbed the data for aircraft position at -118.35016 34.2086 which is 1000' pressure altitude over BUR and did the atmospheric corrections below for this to get the difference between pressure altitude and true altitude. As it turns out they only transited BUR as 500 ft AGL.

Please note this may sound silly, there is actually no uniform sea level, there is a very famous case of a bridge built between Laufenburg (Germany) and Laufenburg (Switzerland) that was out by 54 cm in height because Switzerland being land locked uses the Mediterranean Sea level and Germany uses the sea level near Hamburg, If comparing this data to ground elevation data, you need to be aware of the datum that the elevation data is based upon.

RightRudder · Thu Jan 30, 2020 2:19 pm

zeke wrote:
flybucky wrote:
Here is an updated granular FR24 graph, which has Adjusted Altitude now. The ADS-B Altitude is Pressure Altitude. The Van Nuys METAR at 9:51am PST was A3016. Using a Pressure Altitude calculator, that comes out to 220 ft that needs to be added to the Pressure Altitude.

This makes more sense and matches all NTSB facts. They said the helicopter climbed to 2300 ft at the end, and now the max Adjusted Altitude is 2345 ft. Also, before adjusting, there were points where it seems the heli was less than 100 ft above Hwy 101, which did not seem realistic. Now, the lowest points above 101 would be at least 300 ft.

Also note that the last ADS-B point (9:45:33.7 am, 1570 ft adj alt, -4864 fpm, 161 kts, 91°, ) is not when the heli crashed. From the Ring video, it actually crashed ~6.8s later at 9:45:40.5 am, 1085 ft. That gives an approximate vspeed of (1570-1085)/6.8*60 = -4279 fpm over those last 6.8s. A pretty reasonable value.

Your numbers are out a bit, both BUR and VNY controllers gave 30.19 as the altimeter to 2EX over the radio, that is what they would have been using. I also grabbed the data for aircraft position at -118.35016 34.2086 which is 1000' pressure altitude over BUR and did the atmospheric corrections below for this to get the difference between pressure altitude and true altitude. As it turns out they only transited BUR as 500 ft AGL.

Please note this may sound silly, there is actually no uniform sea level, there is a very famous case of a bridge built between Laufenburg (Germany) and Laufenburg (Switzerland) that was out by 54 cm in height because Switzerland being land locked uses the Mediterranean Sea level and Germany uses the sea level near Hamburg, If comparing this data to ground elevation data, you need to be aware of the datum that the elevation data is based upon.

VNY called off 30.16".

GalaxyFlyer · Thu Jan 30, 2020 2:53 pm

UWS wrote:
I keep wondering why they did not just land at the Van Nuys airport and get a car to TO. That would have taken an hour or so (arrival time 1030), which is only 20 minutes more than flying to Camarillo and then to TO.

Pride and getthereitis won out.

Because this flight under these conditions had been safely completed hundreds of times before and thousands of others just like. Accidents, especially in GA, aren’t often one-offs but the product of many near misses.

RightRudder · Thu Jan 30, 2020 3:21 pm

TYWoolman wrote:
RightRudder wrote:
werdywerd wrote:
Very Detailed Eyewitness account of the accident

https://youtu.be/28QYy8lrww8

The engine sound was normal and then went stilent. It was not the other way around. The engine sound did not quit after the impact explosion, but before. The pilot had already lost controlled flight.

I thought the silence of noise before actual impact was a speed of sound characteristic. The silence we hear is when actual impact occurs, then impact sound travels to ears (?)

When rotary wings hit power lines the sound dramatically changes. The chomp of hovering ceases. The sound of impact follows. (i.e. plexiglass, fiberglass, etc.).

dragon6172 · Thu Jan 30, 2020 3:27 pm

tenHangar wrote:
Maybe not "spatial disorientation" . Could it have been a deliberate abort/u-turn to get below the cloud cover and go back the way he came?

It is one thing to turn around or descend to avoid clouds while VFR... once into the fog/clouds and in IMC conditions the ONLY safe option is a wings level climb to a safe altitude that will keep the aircraft clear of terrain/obstacles.

dragon6172 · Thu Jan 30, 2020 3:53 pm

IADFCO wrote:
Thanks flybucky for the updated charts. I'm intrigued especially by what happens between t=-9.5 sec and t=-8.7 sec. In that 0.8 sec the vertical speed goes from about -1700 ft/min to -3500 ft/min (all figures are approximate because I read them off the chart, and in fact, from the earlier version posted at around page 5 or 6). This corresponds to an acceleration of about -11 m/sec^2 or -1.1g. In the same 0.8 sec the speed goes from 124 to 139 kts, corresponding to an acceleration of about 8.5 m/sec^2 or 0.9g. This seems consistent with a large sudden application of forward longitudinal cyclic, or, which is the same, to a large and sudden "nose down" motion of the rotor disk.

If you look at previous S-76 accidents (you can find a list on Wikipedia), the case of the Copterline Flight 103 is especially interesting. There, a runaway swashplate actuator (one of the orifices of the servovalve got suddenly clogged by a small metal particle) caused a sudden nose up motion of the swashplate, which remained stuck in that nose up position and caused an uncommanded nose up longitudinal stick input, which generated almost 1.8 g, and ultimately caused loss of control and crash of the aircraft.

I'm not implying that a runaway swashplate actuator is involved in this case too, but I think that we should all keep an open mind on mechanical failure as a possible contributing cause to the accident. I wouldn't be surprised if the NTSB investigators looked at swashplate and the overall pitch control chain with particular attention, especially given the Copterline precedent.

PS I'd appreciate if someone repeated the calculations independently.

I actually think those spikes are erroneous data, or out of order data.

djm18 · Thu Jan 30, 2020 5:03 pm

A question here for aviators is why you think he was flying at this speed? It seem relatively fast and wouldn't it make sense to start slowing down as you are starting to come into low clouds and higher terrain?

WIederling · Thu Jan 30, 2020 5:13 pm

Vladex wrote:
I will never fly a copter without a parachute at least .

"Wischmopp".
you get a whirling cloth with some "soft and soggy" attached.

no idea about parachuting from a fully functional copter.

but exiting from one that is in uncontrolled erratic flight is a completely different thing.
Then most chopper crashes are "short transition, fast". either (C)FIT or
parts flying away and the chopper follows to the ground tumbling.

You probably won't have the time to exit anyway.

There were/are some intricate schemes around to get rid of the rotor blades
before you can activate an ejection seat and later get saved by a parachute.

autorotation is the helicopter equivalent to a parachute.

THS214 · Thu Jan 30, 2020 5:51 pm

WIederling wrote:
Vladex wrote:
I will never fly a copter without a parachute at least .

"Wischmopp".
you get a whirling cloth with some "soft and soggy" attached.

no idea about parachuting from a fully functional copter.

but exiting from one that is in uncontrolled erratic flight is a completely different thing.
Then most chopper crashes are "short transition, fast". either (C)FIT or
parts flying away and the chopper follows to the ground tumbling.

You probably won't have the time to exit anyway.

There were/are some intricate schemes around to get rid of the rotor blades
before you can activate an ejection seat and later get saved by a parachute.

autorotation is the helicopter equivalent to a parachute.

This : You probably won't have the time to exit anyway.

When a helicopter starts to spin you won't get out even when there are some time to do it as the g forces are so high that you're part of the plane like glue. Of course we don't know yet if this was the case in this accident not that it matters.

Gtep · Thu Jan 30, 2020 6:17 pm

djm18 wrote:
A question here for aviators is why you think he was flying at this speed? It seem relatively fast and wouldn't it make sense to start slowing down as you are starting to come into low clouds and higher terrain?

The brain is a powerful thing. So let’s put ourselves into his situation. Pilot is in less than favorable conditions. He has been circling for 15 minutes. Finally gets SVFR and at this point is stressed and is ready to “just get there”, put this flight behind him. Pilot starts to think about all the messed up situations he has already encountered in his entire life/career “this is nothing”. Meanwhile, pilot has loss his bearings. Pilot sees the ceiling and decides to push forward only to be met with a hillside. Honestly, I could give you a million reasons as to why this happened. As much as I would love to think that this was mechanical related, I’m just not seeing it and with out additional information from a CVR or FDR we will never know.

SuperiorPilotMe · Thu Jan 30, 2020 6:20 pm

IADFCO wrote:

If you look at previous S-76 accidents (you can find a list on Wikipedia), the case of the Copterline Flight 103 is especially interesting. There, a runaway swashplate actuator (one of the orifices of the servovalve got suddenly clogged by a small metal particle) caused a sudden nose up motion of the swashplate, which remained stuck in that nose up position and caused an uncommanded nose up longitudinal stick input, which generated almost 1.8 g, and ultimately caused loss of control and crash of the aircraft.

I'm not implying that a runaway swashplate actuator is involved in this case too, but I think that we should all keep an open mind on mechanical failure as a possible contributing cause to the accident. I wouldn't be surprised if the NTSB investigators looked at swashplate and the overall pitch control chain with particular attention, especially given the Copterline precedent.

This is admittedly at least generally consistent with apparent observations including the pilot’s apparent experience, tools available to him and eyewitness accounts and preliminary findings about the helicopter’s behavior.

flyingturtle · Thu Jan 30, 2020 6:27 pm

zeke wrote:
Please note this may sound silly, there is actually no uniform sea level, there is a very famous case of a bridge built between Laufenburg (Germany) and Laufenburg (Switzerland) that was out by 54 cm in height because Switzerland being land locked uses the Mediterranean Sea level and Germany uses the sea level near Hamburg,

Just nitpicking: The engineers *did* account for the correct sea level difference of 27 cm, but due to a prefix error, it was verschlimmbessert* - to 54 cm. Luckily, the error was caught early enough, but after construction start.

* verschlimmbessern is a German verb for "trying to correct a fault but you're making it worse in the process."

GalaxyFlyer · Thu Jan 30, 2020 6:30 pm

djm18 wrote:
A question here for aviators is why you think he was flying at this speed? It seem relatively fast and wouldn't it make sense to start slowing down as you are starting to come into low clouds and higher terrain?

How many times has every working pilot asked if everybody’s landing when the weather is near minimums, especially before CAT II and III were so widespread? Or the controller say, everybody’s going to the south of the weather and getting thru that hole in the line? A lot of wind shear accidents started that way.

Experience is no guarantee for the outcome of the next time. The plane or the weather couldn’t care less what your license or logbook says. Or that you have the latest, fanciest instrument panel.

GF

UWS · Thu Jan 30, 2020 6:43 pm

I'm thinking that the odds are extremely low that the AC develops a mechanical problem at the very instant after the pilot makes his very steep ascent. The nest recording supports this. There is nothing unusual about the sound of that helo as it is flying overhead. The other pilot who flies this same chopper also said the odds of mechanical failure are extremely low.

In contrast, the odds of pilot disorientation, or at the very minimum, pilot error in starting the wide left turn, seems much more likely given that this pilot, although instrument rated, had very little IMC experience and given the very poor visibility and low ceilings.

I would also add that pilot fatigue had probably set in to some degree. He was flying for approximately 40 minutes, the last 30 minutes or so were in very poor IMC conditions. If he is not used to that, it could be a contributory factor.

Absent other evidence, you have to go with the odds when drawing conclusions.

In almost all AC mishaps, there are multiple causes that all contribute to the mishap.

flybucky · Thu Jan 30, 2020 7:04 pm

zeke wrote:
Your numbers are out a bit, both BUR and VNY controllers gave 30.19 as the altimeter to 2EX over the radio, that is what they would have been using.

Thanks, appreciate the extra calculations you did. I will just point out that BUR gave 30.19 around 17:16Z, but VNY gave 30.16 around 17:37Z on the radio.

There's also a complete ATC transcript at https://www.washingtonpost.com/transpor ... ant-crash/

THS214 · Thu Jan 30, 2020 7:23 pm

GalaxyFlyer wrote:
djm18 wrote:
A question here for aviators is why you think he was flying at this speed? It seem relatively fast and wouldn't it make sense to start slowing down as you are starting to come into low clouds and higher terrain?

How many times has every working pilot asked if everybody’s landing when the weather is near minimums, especially before CAT II and III were so widespread? Or the controller say, everybody’s going to the south of the weather and getting thru that hole in the line? A lot of wind shear accidents started that way.

Experience is no guarantee for the outcome of the next time. The plane or the weather couldn’t care less what your license or logbook says. Or that you have the latest, fanciest instrument panel.

GF

True!

About the first part: Back in the 1970s (and 80s) Finns said that "our pilots are so good and brave that when others go-around Finnish pilots land". Later a pilot of that company told that legally they didn't have minimums while others did. That airline (Spearair with 2 DC-8s) didn't last more than couple of years. Luckily so they didn't make a big ground.

When I was young I believed it. No I know it was stupid.

flybucky · Thu Jan 30, 2020 7:25 pm

GalaxyFlyer wrote:
This from an experienced helo and powered lift pilot at PPW

Thanks, this was great info.

However, if I knew a IMC penetration was imminent or I had already punched in, I would've immediately started a max performance level attitude climb while simultaneously slowing to "bucket speed". If I were ahead of the game I would already have slowed down anticipating the possible need for maximum energy

I looked up "bucket speed" and looks like it is the optimum speed for maximum climb rate. For the Bell 412, bucket speed is 70 kts.

I would've maintained that straight ahead climb until I reached at least the MEF for the region or punched out of the fog. The only way I would've turned is if I had a system showing me high terrain in front or me thereby necessitating a turn. Any unnecessary turn would only raise the risk of inducing vertigo at this point, especially for a pilot that isn't comfortable in IMC.

This is why my theory is that the pilot was not trying to turn back, but it was an accidental turn due to lack of visual cues in the fog.

His desire to maintain VMC was paramount and evident in the turn to the left, which I believe increased in bank angle as he attempted to stay visual. Once IMC it put him in an attitude that was very susceptible to inducing vertigo/SD. It also produced an overbanked attitude where his only recourse is to slow down rapidly or level the helo, your resultant lift vector gets large very quickly here in the direction you don't want it to be pointing.

This would contradict my theory above. Is the PPW poster is saying that the pilot turned left on purpose towards the mountains, in order to have visual cues?

flybucky · Thu Jan 30, 2020 7:47 pm

trnswrld wrote:
Wow that audio is interesting (and sad) to listen to. What I find interesting is it appears to move very slowly overhead or even stationary, Then starts to move away(possibly quickly), then just crashes.

Yes, it was almost overhead, but it was not stationary.

The nest video starts at 9:45:01 am. At that time, the heli was at 34.1481, -118.6981 (intersection of 101 and Las Virgenes Rd) and over 1000 ft AGL. Ground speed was 114 kts (131 mph), so it was moving fast.

Probably what you're hearing is when the helicopter is overhead, the distance to the Nest is not changing that much (still around 1000 ft overhead). But when it gets farther away, then the distance to the Nest increases faster (131 mph = 192 ft/s).

flybucky · Thu Jan 30, 2020 7:53 pm

tenHangar wrote:
Maybe not "spatial disorientation" . Could it have been a deliberate abort/u-turn to get below the cloud cover and go back the way he came?

That's what some early theories were. But looking at more info, it doesn't make sense. The ceiling was only 1100 ft, barely above ground level. Why would he go back down? And at the end, he was going 161 kts (max speed is 155 kts). That doesn't seem like a deliberate descent.

JayinKitsap · Thu Jan 30, 2020 8:00 pm

zeke wrote:

Please note this may sound silly, there is actually no uniform sea level, there is a very famous case of a bridge built between Laufenburg (Germany) and Laufenburg (Switzerland) that was out by 54 cm in height because Switzerland being land locked uses the Mediterranean Sea level and Germany uses the sea level near Hamburg, If comparing this data to ground elevation data, you need to be aware of the datum that the elevation data is based upon.

No uniform sea level is correct. In the US area the surveyor's data for Elevation 0.0 is mean sea level, which was the average sea level on a particular date 'lock', the most common here was NGVD 1929 which set elevation 0 for all of the USGS topo maps and surveyor information. However, in waterfront work we use 0.0 as the Mean Lower Low Water as the average of the lower daily tide each day. Tide ranges are from about -4.5 to +13.1 at the main Seattle Tide Gauge. This reference for tidals changes with each major bay. There is around a 7.5 foot difference between the two 0.0's, really messes things up when trying to tie up the two.

NGVD 1929 is now dead, superseded by NGVD88, which will be replaced in a few years. This new zero is based on lots of mapping this out of round sphere called earth. It is a real pain in the ass to change the datum standard. Imagine adjusting all of the contours and data points by 0.2' with the change. Why I still see NGVD29 information because it wasn't ever changed.

https://www.ngs.noaa.gov/datums/vertica ... 1929.shtml

THS214 · Thu Jan 30, 2020 8:06 pm

flybucky wrote:
tenHangar wrote:
Maybe not "spatial disorientation" . Could it have been a deliberate abort/u-turn to get below the cloud cover and go back the way he came?

That's what some early theories were. But looking at more info, it doesn't make sense. The ceiling was only 1100 ft, barely above ground level. Why would he go back down? And at the end, he was going 161 kts (max speed is 155 kts). That doesn't seem like a deliberate descent.

How do you calculate that ceiling? Mean sea level or above ground. The latter is what ATC reports. At the accident site (this is what matters) weather could have been lot worse than at the nearest weather station.

rfields5421 · Thu Jan 30, 2020 8:13 pm

UWS wrote:
I keep wondering why they did not just land at the Van Nuys airport and get a car to TO. That would have taken an hour or so (arrival time 1030), which is only 20 minutes more than flying to Camarillo and then to TO.

Pride and getthereitis won out.

I take issue with what I see as an unsupported assumption.

The weather was not 'very bad' when the flight departed.

Bryant was an experienced passenger. I doubt it was possible that he did not recognize that conditions were getting worse. But I could be wrong.

Also as a parent, apparently a good one, I doubt he would risk his child's life for a basketball game if he thought it was dangerous. Yes, she might be extremely disappointed, but at least she would be alive to be disappointed..

This is not like the 2001 G-3 crash at Aspen, the classic 'getthereitis' crash. Where the investigation uncovered the push by the client, and the pilot refusal to disappoint the client.

We will never know what Bryant said, or did not say. Or if the pilot communicated his intentions/ plans to anyone else.

If Bryant were that type of client the pushed a pilot to take chances, I think we would have heard about it already.

People make judgmental mistakes every day. Some have horrible consequences.

Personally, I see it as a tragic instance of a pilot pushing too far trying to please a client, trying one last thing before turning back. It was a bad decision.

But I also have to admit that I will never know for sure why the bird crashed.

slvrblt · Thu Jan 30, 2020 9:36 pm

I don't think we'll ever know for sure what the final answer is to this tragedy. Lots of good points here in the discussion. I very strongly favor spatial disorientation. I just experienced it, albeit on the ground, not in the air. Nevertheless, I was pretty freaked out, I wouldn't have believed how profound it can be. Here is my experience:

I have made the drive on I-10 from my father-in-laws house in Gulfport to New Orleans and back countless times. Driven in the fog too. But last week, as I made the drive again.....there was heavy fog, more than I've ever seen. In hindsight, I shouldn't have been on the road. It was early in the morning, very few people out, so no big deal, I thought. No traffic, no one to hit. Nope...bad idea.

Coming out of New Orleans, it wasn't bad at all, there was patchy fog, no biggie. But on the approaches to I-10 it began to get worse. And worse. It was hard to make things out, I could barely see. Even though I knew the way, not being able to see landmarks or ground cues found me wandering the lanes as my situational awareness slowly eroded. Once I nearly missed a curve and had to swerve to get back on track. Then I got really scared crossing Lake Ponchartrain. The fog obscured nearly everything. You lose three-dimensional perception, I couldn't see the guardrail, could barely see lane markers.
A couple of times my brain was screaming at me that I was about to go over the guardrail into the water. I slowed WAY down, could finally see some lane markers, and calmed down. Finally I pulled off at a gas station to get some coffee and chill out. Semi tractor trailers were parked all over the side of the exit, and even on the interstate shoulders, position lights glowing and flashers on. ''You're the only stupid idiot driving'' I berated myself. There were a few other cars out and about, but clearly this was not a smart idea.

So, I could understand how this pilot, experienced as he was, could still get disoriented. He's without instrument guidance, and visual cues are disappearing or have gone. In that high-speed dive to the ground, he may have thought he was moving up, to clear the hills, up and out of the trouble's way, fast. Who knows. Once your brain loses its lock on where it is, your senses play nasty tricks on you and the outcome is bad.

ikramerica · Thu Jan 30, 2020 9:45 pm

rfields5421 wrote:
UWS wrote:
I keep wondering why they did not just land at the Van Nuys airport and get a car to TO. That would have taken an hour or so (arrival time 1030), which is only 20 minutes more than flying to Camarillo and then to TO.

Pride and getthereitis won out.

I take issue with what I see as an unsupported assumption.

The weather was not 'very bad' when the flight departed.

Bryant was an experienced passenger. I doubt it was possible that he did not recognize that conditions were getting worse. But I could be wrong.

Also as a parent, apparently a good one, I doubt he would risk his child's life for a basketball game if he thought it was dangerous. Yes, she might be extremely disappointed, but at least she would be alive to be disappointed..

This is not like the 2001 G-3 crash at Aspen, the classic 'getthereitis' crash. Where the investigation uncovered the push by the client, and the pilot refusal to disappoint the client.

We will never know what Bryant said, or did not say. Or if the pilot communicated his intentions/ plans to anyone else.

If Bryant were that type of client the pushed a pilot to take chances, I think we would have heard about it already.

People make judgmental mistakes every day. Some have horrible consequences.

Personally, I see it as a tragic instance of a pilot pushing too far trying to please a client, trying one last thing before turning back. It was a bad decision.

But I also have to admit that I will never know for sure why the bird crashed.

I’m not a Bryant fan in any way, but I agree that I don’t think he would push them to keep going in zero visibility.

Having driven that stretch of 101 dozens of times including getting off the highway at most of the exits and taking a test drive through the surrounding roads, I think what happened was very simple.

Things deteriorated rapidly as they approached Calabasas Mercedes and the first opportunity to turn back was that residential area near Las Virgines. While not quite as steep, think of the stretch before La Virgines like something out of Star Wars (1 or 5). Can’t go left, can’t go right.

The experienced pilot knew that area well. He had taken them that way many times before. But the turn around execution failed and we will hopefully find out why. My guess is that off the highway to the left the fog cover was even denser as it got stuck in the mountain bowl.

flybucky · Thu Jan 30, 2020 9:54 pm

THS214 wrote:
How do you calculate that ceiling? Mean sea level or above ground. The latter is what ATC reports.

Oh thanks, didn't know that. I had been assuming wrongly that the ceiling was specified MSL. Yeah, that makes a big difference.

VNY ATC said 1100 ft ceiling. Elevation at VNY is 802 ft. So that means ceiling about 1900 ft MSL at VNY.

At 101 and Las Virgenes Rd, the spot where the heli turned from 101, the elevation was about 800 ft, similar to VNY. But like you said, who knows what level the clouds were in that area.

MrBretz · Thu Jan 30, 2020 10:40 pm

ikramerica said : "Having driven that stretch of 101 dozens of times including getting off the highway at most of the exits and taking a test drive through the surrounding roads, I think what happened was very simple.

Things deteriorated rapidly as they approached Calabasas Mercedes and the first opportunity to turn back was that residential area near Las Virgines. While not quite as steep, think of the stretch before La Virgines like something out of Star Wars (1 or 5). Can’t go left, can’t go right.

The experienced pilot knew that area well. He had taken them that way many times before. But the turn around execution failed and we will hopefully find out why. My guess is that off the highway to the left the fog cover was even denser as it got stuck in the mountain bowl."

I haven't driven the road as much as you but I have driven 101 many times over many years. And I think what your describe must have happened. I see no reason for the left turn off the 101 except if the fog was really thick ahead and he wanted to go back the way he came. Then something happened, he lost it, and they crashed. Poor souls.

zeke · Thu Jan 30, 2020 10:46 pm

flybucky wrote:
Thanks, appreciate the extra calculations you did. I will just point out that BUR gave 30.19 around 17:16Z, but VNY gave 30.16 around 17:37Z on the radio.

There's also a complete ATC transcript at https://www.washingtonpost.com/transpor ... ant-crash/

I don’t think it matters much to the calculations I made for true altitude, to do that you need to know how much air is below the aircraft. Anything below ground level does not expand and contract in relation to changes in QNH and temperature. It is only the column of air between the ground and the aircraft.

The did not fly over VNY but did over BUR, VNY is about 20-30 ft higher than BUR. That is why I used BUR.

It appears you lack some if the fundamentals and are just plugging in numbers to a website without understanding the principles.

As they say, garbage in garbage out.

IADFCO · Thu Jan 30, 2020 11:28 pm

dragon6172 wrote:
IADFCO wrote:
Thanks flybucky for the updated charts. I'm intrigued especially by what happens between t=-9.5 sec and t=-8.7 sec. In that 0.8 sec the vertical speed goes from about -1700 ft/min to -3500 ft/min (all figures are approximate because I read them off the chart, and in fact, from the earlier version posted at around page 5 or 6). This corresponds to an acceleration of about -11 m/sec^2 or -1.1g. In the same 0.8 sec the speed goes from 124 to 139 kts, corresponding to an acceleration of about 8.5 m/sec^2 or 0.9g. This seems consistent with a large sudden application of forward longitudinal cyclic, or, which is the same, to a large and sudden "nose down" motion of the rotor disk.

If you look at previous S-76 accidents (you can find a list on Wikipedia), the case of the Copterline Flight 103 is especially interesting. There, a runaway swashplate actuator (one of the orifices of the servovalve got suddenly clogged by a small metal particle) caused a sudden nose up motion of the swashplate, which remained stuck in that nose up position and caused an uncommanded nose up longitudinal stick input, which generated almost 1.8 g, and ultimately caused loss of control and crash of the aircraft.

I'm not implying that a runaway swashplate actuator is involved in this case too, but I think that we should all keep an open mind on mechanical failure as a possible contributing cause to the accident. I wouldn't be surprised if the NTSB investigators looked at swashplate and the overall pitch control chain with particular attention, especially given the Copterline precedent.

PS I'd appreciate if someone repeated the calculations independently.

I actually think those spikes are erroneous data, or out of order data.

Is this your own guess, or you are basing it on something specific? I'm not asking to be confrontational, it's that so far these are the only hard data available on the accident, so any decision to dismiss them should not be taken lightly.

dragon6172 · Fri Jan 31, 2020 12:13 am

IADFCO wrote:
dragon6172 wrote:
I actually think those spikes are erroneous data, or out of order data.

Is this your own guess, or you are basing it on something specific? I'm not asking to be confrontational, it's that so far these are the only hard data available on the accident, so any decision to dismiss them should not be taken lightly.

It is a guess, but I base it on the fact when you look at the raw data in a spreadsheet format you can see some of those weird spikes coincide with "jumps" backwards on Lat/Long, which would be impossible.

GalaxyFlyer · Fri Jan 31, 2020 12:20 am

The NTSB has loads of tools to look collate the ADS, radar data, plus metallurgical analysis of the evidence plus any video subject to lab analysis to plot the final minutes of the flight. Those sp”spikes” will be analyzed and smoothed based on the physics of flight. Trying to run your own investigation with open source information is not very productive. The investigation team will spend a year pouring over every aspect and usually finds some surprises and some obvious causal factors.

TimG100 · Fri Jan 31, 2020 12:44 am

I'm hoping to better understand what it means when an operator is said to be "VFR only", as opposed to a pilot or aircraft being "VFR only". Specifically, let's assume the pilot and aircraft are both IFR-certified and current. If flight conditions deteriorate en route, I'm assuming that if flying for a "VFR-only" operator, that means the pilot is supposed to divert prior to encountering IMC and land VFR, just as a VFR-only pilot would be required to do. But if the pilot is in deteriorating marginal conditions, could the pilot get an IFR clearance (exercising their authority as PIC to do what's safest, even if potentially getting into trouble with the company), or would they need to declare an emergency with ATC, just as a VFR-only pilot would be expected to do in the same situation?

flybucky · Fri Jan 31, 2020 1:05 am

Canuck600 wrote:
There are comments on PPRUNE that FlightRadar24 data is not reliable in that sort of terrain? Everybody here seems to treat FR24 data like it's gospel but I wonder?

dragon6172 wrote:
I actually think those spikes are erroneous data, or out of order data.

I think this is a good topic. I often see people mention that flight tracker data isn't always reliable, but what exactly can be unreliable about it? After all, those values are directly coming on onboard instruments. It's not like some they're some estimated values from an outside third-party measurement.

Here's my thoughts about what is/isn't reliable about ADS-B / flight tracker data. Feel free to correct or add more:

Timestamp - Assuming the timestamp on the ADS-B message comes from the transmitter, this should always be 100% accurate (Unless the time on the transmitter was off. But even then, the relative time would be accurate, so you would not get out-of-order data.)

Lat/Long - This comes from the onboard GPS. This could be slightly off as GPS isn't always perfectly accurate. This could explain some of the "backtracking" that you see in data, especially the granular data. But I think it is a result of GPS and not out-of-order data.

Altitude - This one is often misused because ADS-B uses standard Pressure Altitude in ft (like Flight Level). So it's not that it's wrong, but often people treat it as True Altitude or AGL. Otherwise the Pressure Altitude should be mostly accurate (in 25 ft increments). And even if misused, at least the Relative Altitude would be accurate.

Speed - is the horizontal ground speed in kts. I'm not sure if it comes from GPS or IRS (inertial reference system).

VSpeed - is the vertical speed in fpm. I believe this comes from IRS.

Track - degrees. I assume this would be accurate.

ADS-B receiver - In mountainous terrain, the receiver may not be able to pick up the ADS-B signals. So it may be missing some. Or in this case, I believe the last ~7s of ADS-B signals were missing because it dipped below the ridge (the numbers check out. The last ADS-B was 1570 adj altitude. The ridge was 1500 ft.) But again, you will be able to tell in the data if signals were dropped by gaps in the timeline.

Flight tracking websites - By default, they may only save/use the ADS-B data like every 30 seconds or 1 minute (otherwise too much data for them). This can lead to misleading conclusions because they interpolate or smooth the graph with very sparse data points. That's fine for normal, smooth flights. But when something goes wrong, the flight tracking sites may not show it because the data points are too sparse. Thankfully, FR24 will usually publish the granular data for major incidents. That gives the ADS-B data about every 2s.

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