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GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 11:56 am

Less a question density altitude than angle of bank and g loading, both unknown until the FDR is read.

Elsewhere the presumed PF was known as an experienced aerobatic pilot for what that’s worth.
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 12:06 pm

GalaxyFlyer wrote:
Less a question density altitude than angle of bank and g loading, both unknown until the FDR is read.

Elsewhere the presumed PF was known as an experienced aerobatic pilot for what that’s worth.


Density altitude is a factor, turns are a function of TAS and angle of bank. For a given IAS at higher density altitude, they require a higher angle of bank to achieve the same turn rate or radius of turn to stay within the circling area. Not being aware of this may result in overshooting the turn onto final.
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OldB747Driver
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 2:14 pm

I apologize for not being more specific in my attempt to equivocate Part 121 Ops onto what was, apparently, a Part 91 operation. I think @CanukinUSA did an excellent job of illustrating that Part 121 does, indeed, fly circling approaches, in many instances they are limited by the OpSpec for the operation, but circling never-the-less. But in my mind, that's really not the point - I'm simply trying to compare apples to apples (managing risk in a flight scenario) rather than apples to oranges (Part 121 to Part 91) where there is less regulation and consequence to one's actions when no metal is bent or airspace blundered into.

I get the feeling you're trying to convey that this crew and its flight path were "pretty much" normal. I am trying to convey that there seems to be forensic evidence that this approach, which experienced pilots will likely agree, has a higher level of risk and thus requires a higher level of performance/execution to accomplish safely, was not normal.

While I can appreciate your analysis of the speeds and trying to justify them, given the overall risk associated with this approach, how would you characterize an average descent rate of 3,500 FPM for about a full minute leading to the final 5 minutes of this flight? That's not just aggressive, that's extreme and one would have to assume, executed because they were "behind" where they knew they needed to be.

At times in my career I've done some pretty steep [visual] approaches at high altitude airports successfully (& safely) but the "trick" has always been to be configured early, not punching my ticket "a little quick" at each gate on a high risk approach, or in other words, planned. I'm having trouble seeing that in this case.
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 2:45 pm

OldB747Driver wrote:
While I can appreciate your analysis of the speeds and trying to justify them, given the overall risk associated with this approach, how would you characterize an average descent rate of 3,500 FPM for about a full minute leading to the final 5 minutes of this flight? That's not just aggressive, that's extreme and one would have to assume, executed because they were "behind" where they knew they needed to be.


For me through my entire career its always been the 1 minute rule, never have a rate of descent that will put you in the ground within a minute at your current altitude. Many times in my career I have had to shuttle down in a valley before starting an approach, this never has concerned me above MSA. In HKG it is very common to do in excess of 6000 fpm descent from SIERA onto runway 07, they put you over SIERA at FL190 and we aim to be passing the IAF a few minutes later at 5000' at 500 fpm and 250 kts (MSA4300).

OldB747Driver wrote:
At times in my career I've done some pretty steep [visual] approaches at high altitude airports successfully (& safely) but the "trick" has always been to be configured early, not punching my ticket "a little quick" at each gate on a high risk approach, or in other words, planned. I'm having trouble seeing that in this case.


I dont disagree with you, I have always been a fan of gear down and half my flap to get rid of energy over speedbrake during an approach. I personally use gear over speedbrake at lower speeds. Their profile at LUMNO seems reasonable to me, 10+ nm to run, 3500' above field elevation at 190 KIAS, I would be comfortable with that in a widebody .
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
ClimberTroy
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 6:57 pm

I joined this forum to have a question answered, I don't have any aviation knowledge but was on the golf course that day and was about 100 yards from impact. Let me start by stating I noticed the sound was lower that the rest of the jets that day, I turned to locate the jet and then heard the sound change from a normal jet sound to a high pitched "squeal", a sound that is normal in movies when the decent become extreme. AS ring doorbell shows impact and it was a very steep angle. About 3 seconds or so of hearing that sound I heard impact and then then explosion. We were at the site within a few minutes. In hearing the radio contact there was no indication of a problems, and roughly 10 seconds after the last contact the tower saw smoke .... on the ground were two Cirrus Aviation "employees/pilots. Seems very weird they could be on site so quickly, ideas?
 
OldB747Driver
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 7:57 pm

Thanks for sharing that information with us, ClimberTroy. I'll only speak to the possibilities based on conjecture and experience (I am a retired airline pilot).

The difference in noise is likely due to what a turbojet sounds like at idle power vs. a turbojet producing some amount of thrust. A large amount of the noise a jet engine makes is due to the sound waves associated with the shear zone between a jet engine's high velocity output and the air it is flying through. When a jet engine is at idle, that noise component is largely removed and the mechanical noise of the running engine not producing significant thrust is the noise you likely heard initially. The increased whine may have been the noise you would hear as the engine internal parts accelerate (increase thrust output) but are not yet producing enough thrust that, in turn, creates the lower frequency "tearing" noise you heard with the other jets that day.

Jet engines at low idle can take up to ~8 seconds to fully accelerate from idle to full thrust. As a result, the ideal landing profile is one where we maintain a small amount of power all the way to the landing flare - that small amount of power places us within 2-3 seconds of full acceleration should it be needed. If a jet is too fast on the approach, however, there are not many options to slow down while continuing to a landing and your observation may well sustantiate that that was what occurred.
 
ClimberTroy
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Re: Bombardier CL 600 down near Truckee, California

Sat Jul 31, 2021 10:19 pm

Any ideas how the two Cirrus guys were on scene do quickly?
 
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Aaron747
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 12:06 am

ClimberTroy wrote:
Any ideas how the two Cirrus guys were on scene do quickly?


Maybe coming back to the field from picking up lunch, and they spotted the fire?
If you need someone to blame / throw a rock in the air / you'll hit someone guilty
 
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Aaron747
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 12:13 am

GalaxyFlyer wrote:
Less a question density altitude than angle of bank and g loading, both unknown until the FDR is read.

Elsewhere the presumed PF was known as an experienced aerobatic pilot for what that’s worth.


Interesting with the aerobatic experience. Suppose they inadvertently left the speedbrakes out into a high bank angle turn?
If you need someone to blame / throw a rock in the air / you'll hit someone guilty
 
OldB747Driver
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 12:17 am

ClimberTroy wrote:
Any ideas how the two Cirrus guys were on scene do quickly?

Coincidence - Cirrus has no relationship to Bombardier as far as I'm aware.

Pilots on a golf course near an airport are probably as rare as ants at a picnic!
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 12:19 am

ClimberTroy wrote:
I turned to locate the jet and then heard the sound change from a normal jet sound to a high pitched "squeal", a sound that is normal in movies when the decent become extreme.


I would describe that as the doppler effect, you were essentially stationary, as the aircraft turned towards you the distance from the aircraft to you would be decreases so the frequency of the sound would increase until it starts going away from you.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
ClimberTroy
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 8:58 am

OldB747Driver wrote:
ClimberTroy wrote:
Any ideas how the two Cirrus guys were on scene do quickly?

Coincidence - Cirrus has no relationship to Bombardier as far as I'm aware.

Pilots on a golf course near an airport are probably as rare as ants at a picnic!


They did not have golf shoes on, I/we had played 12 holes or so, we knew who was in front of us....they weren't playing golf.
 
OldB747Driver
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 1:52 pm

Do you suppose they had some level of expectation of the accident? I'm not sure what you are trying to determine...

The nature of the piloting job is sitting for a LOT of time and being "stuck" at airports waiting (for our passengers, cargo, the boss to get back from their meeting, etc.) and it's really not unusual at all for us to take a walk while waiting, especially in a beautiful area like Lake Tahoe.
 
ClimberTroy
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Re: Bombardier CL 600 down near Truckee, California

Sun Aug 01, 2021 6:26 pm

My thought was and I don't know if this is possible but they knew the pilot. And had communication with him and knew there was a problem. BUT there want a problem based on the communication with the tower. the airport is just far enough away that it was impossible to be there and leave to arrive at the accident that quickly. I guess coincidentally they were headed away or to the airport and it was just timing, parked their ca along the road r and ran across the course
 
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Aaron747
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 02, 2021 1:24 am

ClimberTroy wrote:
My thought was and I don't know if this is possible but they knew the pilot. And had communication with him and knew there was a problem. BUT there want a problem based on the communication with the tower. the airport is just far enough away that it was impossible to be there and leave to arrive at the accident that quickly. I guess coincidentally they were headed away or to the airport and it was just timing, parked their ca along the road r and ran across the course


Not possible. Not only would it be distracting but there isn’t time for crew to contact outside parties other than ATC in the final minutes of a landing approach. Especially in a high workload environment like Truckee.

Whatever the final accident sequence was, it developed quickly and was not communicated.
If you need someone to blame / throw a rock in the air / you'll hit someone guilty
 
OldB747Driver
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 02, 2021 3:43 am

Like @Aaron747 said, most pilots and aviation professionals who have reviewed the known information have good reason to believe that, as far as this unfortunate crew was concerned, they were unaware of their predicament until, literally, only a few seconds before impact, which would predispose the possibility of even communicating with the tower, much less anyone else.

The only debate that is really being considered in most circles is whether there was a very untimely, and currently unknown problem at low atlitude or whether the pilot/crew made an error in either flight path and/or systems operation while making a challenging approach.
 
Thenoflyzone
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 02, 2021 3:47 am

zeke wrote:
93Sierra wrote:

Wrong it’s a cat d for circling cat c for straight in


A bit of background here, in the US as you know charts are designed to a standard called TERPS, where the majority of the world uses PAN-OPS. The area around an airport that is assessed for obstacles and terrain under TERPS is smaller than PAN-OPS. As a result operations within TERPS circling areas may require higher angles of bank, which makes circling under this criteria as higher risk.

Under ICAO/PAN-OPS there is only one approach category, for example under ICAO the A320 is Cat C where under TERPS it’s the same as the 605 CAT C straight in and CAT D circling.

If this was an ICAO procedure to the same airport the circling minina would be higher, however the circling area would be larger (lower bank angles), requiring higher vis.

Hopefully this accident will prompt a new RNP(AR) to be developed to improve safety for these larger aircraft.


There was a change to the TERPS criteria in 2012 that affects circling area dimensions by expanding the areas to provide improved obstacle protection. Under the previous TERPS criteria, the radii used to define the size of these arcs were relatively small, especially for category C and D operations. (Ex. CAT C was 1.7nm, regardless of MDA) To indicate that the new criteria has been applied to a given procedure, a inverse C in a black box is placed on the circling line of minimums. TRK's RNAV 20 has the new circling criteria.

Like I said, the previous TERPS criteria before 2012 used a radius of 1.7 nm from the end of the runway for a Category C aircraft. Under the new guidelines, that radius increased to 2.7nm. In the case of TRK's RNAV 20, which has an MDA of 7700ft for CAT C aircraft on the circling approach, that radius increases to 3.2 nm, which is considerably larger than the previous 1.7 nm.

While these radii are smaller than those used in ICAOs PANS-OPS, they represent a significant improvement over the previous TERPS criteria. Of note, bank angle requirements during circling for CAT C and D aircraft both under PANS-OPS and TERPS are identical, which is 20 degrees.
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 02, 2021 2:40 pm

Thenoflyzone wrote:
Like I said, the previous TERPS criteria before 2012 used a radius of 1.7 nm from the end of the runway for a Category C aircraft. Under the new guidelines, that radius increased to 2.7nm. In the case of TRK's RNAV 20, which has an MDA of 7700ft for CAT C aircraft on the circling approach, that radius increases to 3.2 nm, which is considerably larger than the previous 1.7 nm.

While these radii are smaller than those used in ICAOs PANS-OPS, they represent a significant improvement over the previous TERPS criteria. Of note, bank angle requirements during circling for CAT C and D aircraft both under PANS-OPS and TERPS are identical, which is 20 degrees.


Thanks I was aware of change 21, personally I don’t like how any of those approaches have circling approved as the MDA is outside the circling area. On that RWY20 RNAV the MDA is 4.7 mm to the runway, it is a accident waiting to happen.
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GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 02, 2021 2:54 pm

How is the MDA outside the circling area? That’s not even a TERPS requirement, IIRC, may have changed in 21. The designer does not have to establish a CDA the puts the highest category vertical path intercepting the MDA inside the circling area.
 
CanukinUSA
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 02, 2021 8:31 pm

Using the latest version of FAA Order 8360.3E TERPS "Terminal En-Route Procedures" issued on 09/17/2020 online, I have calculated the True Airspeed and Circling Approach Radius for the approach and circling maneuver at KTRK. TERPS is available online at:
https://www.faa.gov/regulations_policie ... ntTopicID=
Using the formulas listed in TERPS Section 2-7 Circling Approach and Sidestep Maneuvers 3-7-1 Circling Approach Area Page 2-58.
The numbers I obtain are:
1) VTAS = 161 Knots using 140 KIAS, 7700 feet
2) Circling Approach Radius (CAR) 3.28 NM (using Category C aircraft at 161 KTAS, 0.5 NM Straight in allowance and 20 degrees of bank.).
Hopefully, these numbers are correct as it has been 46 years since I had to do calculations like this in Engineering. Please feel free to check the numbers for errors.

I see 2 potential issues with this.
1) Since the one would reach Circling MDA on this RNAV approach at BOFFS intersection which is 4.7 NM from the runway 20 landing threshold if one spots the other runway and starts turning right when you reach MDA you would likely be outside the obstacle protected area during the turn to downwind Runway 11 and could still possibly be outside your obstacle protected area after the turn on to downwind for Runway 11.
2) If one proceeded at MDA towards Runway 20 as you should to ensure obstacle clearance until reaching 3.28 NM from the threshold of Runway 20 before starting the circling maneuver or even closer to the threshold due to not spotting the runway in reduced visibility you could put yourself in a situation where you would have to maneuver at greater angles of bank to accomplish the circling maneuver to land on Runway 11. If you have a tailwind at circling altitude and below while circling this would not help matters.
My best guess is that 2) is more applicable in this case given what appears to have happened. This is speculation right now as none of us know any of the details at this time like the accident investigators will know when they start analyzing the data from the recorders and other sources.
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 2:42 am

GalaxyFlyer wrote:
How is the MDA outside the circling area? That’s not even a TERPS requirement


Exactly my point, flying a CDA as it is designed, you reach the CMDA outside the circling area. And the circling area is greater than the visibility requirements. And the VDA from the CMDA would be greater than 3.77 degrees. Notice the straight in on 11 is also 3.77 degrees ?

CanukinUSA wrote:
Hopefully, these numbers are correct as it has been 46 years since I had to do calculations like this in Engineering. Please feel free to check the numbers for errors.


Look pretty good to me, except with the temps being so high at the time the TAS is probably going to more like 165 kts.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
CanukinUSA
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 2:51 am

Interestingly as far as I can tell they do not have any correction for temperature in their formulas.
 
GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 3:23 am

zeke wrote:
GalaxyFlyer wrote:
How is the MDA outside the circling area? That’s not even a TERPS requirement


Exactly my point, flying a CDA as it is designed, you reach the CMDA outside the circling area. And the circling area is greater than the visibility requirements. And the VDA from the CMDA would be greater than 3.77 degrees. Notice the straight in on 11 is also 3.77 degrees ?

CanukinUSA wrote:
Hopefully, these numbers are correct as it has been 46 years since I had to do calculations like this in Engineering. Please feel free to check the numbers for errors.


Look pretty good to me, except with the temps being so high at the time the TAS is probably going to more like 165 kts.


True, upon reaching the circling MDA, you drive in at the MDA until within the circling airspace, maneuver to align the landing runway. There’s not relationship between the CDA and the circling MDA as it’s not a straight in approach. The terrain dictates the 3.77 degree paths. Circling is, by definition, a “dive and drive” approach. Lots of circling approaches designed this way in TERPS.
 
CanukinUSA
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 3:55 am

The main problem with the circling area is that how many pilots would know what the Circling Area Radius for a particular airport is? And know how to calculate it if they don't? And who has time to calculate it while on an approach in the aircraft? The calculation took me about 30 minutes, and I was sitting at my computer desk not flying an aircraft. I suppose that you can develop some thumb rules for that, but one is usually busy enough with other duties to calculate this. I think that some human factors engineering needs to be looked at with this. Whether it is worth the effort is debatable as I expect that circling approaches will eventually disappear as other better approach procedure methods continue to be developed and put in use that do not require circling.
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 10:02 am

GalaxyFlyer wrote:
There’s not relationship between the CDA and the circling MDA as it’s not a straight in approach.


That approach is designed as a CDFA. When change 21 came in there was a lot of discussion on what to do once in the circling area. The consensus at that stage and I’m pretty sure is was in the FAA letters published at the time the expectation is for a continuous stable descent from the MDA to landing. What your advocating in terms a dive and drive within circling area is not smart in any jet.

CanukinUSA wrote:
I suppose that you can develop some thumb rules for that, but one is usually busy enough with other duties to calculate this.


These links should work for you, there are charts around that have speed angle of bank and give you radius of turn.


http://www.wolframalpha.com/input/?i=%2 ... 29%5E2.628

http://www.wolframalpha.com/input/?i=2% ... 9%5D%2B0.5
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
hitower3
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 10:09 am

ClimberTroy wrote:
I joined this forum to have a question answered, I don't have any aviation knowledge but was on the golf course that day and was about 100 yards from impact. Let me start by stating I noticed the sound was lower that the rest of the jets that day, I turned to locate the jet and then heard the sound change from a normal jet sound to a high pitched "squeal", a sound that is normal in movies when the decent become extreme. AS ring doorbell shows impact and it was a very steep angle. About 3 seconds or so of hearing that sound I heard impact and then then explosion. We were at the site within a few minutes. In hearing the radio contact there was no indication of a problems, and roughly 10 seconds after the last contact the tower saw smoke .... on the ground were two Cirrus Aviation "employees/pilots. Seems very weird they could be on site so quickly, ideas?


Dear ClimberTroy,

Did you consider to share your observations with the FAA? https://www.faa.gov/contact/
Even though the data recorders will provide valuable information, eye witness reports may be of interest for them too.

Kind regards,
Hendric
 
GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 2:16 pm

zeke wrote:
GalaxyFlyer wrote:
There’s not relationship between the CDA and the circling MDA as it’s not a straight in approach.


That approach is designed as a CDFA. When change 21 came in there was a lot of discussion on what to do once in the circling area. The consensus at that stage and I’m pretty sure is was in the FAA letters published at the time the expectation is for a continuous stable descent from the MDA to landing. What your advocating in terms a dive and drive within circling area is not smart in any jet.

CanukinUSA wrote:
I suppose that you can develop some thumb rules for that, but one is usually busy enough with other duties to calculate this.


These links should work for you, there are charts around that have speed angle of bank and give you radius of turn.


http://www.wolframalpha.com/input/?i=%2 ... 29%5E2.628

http://www.wolframalpha.com/input/?i=2% ... 9%5D%2B0.5


There’s no way the FAA or PANS-OPS could produce a circling approach that includes a constant descent path to the threshold—too many variables. True, RNP AR could be the fix, but the FAA has made it near impossible for non-airline operators to get approval.
 
CanukinUSA
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 6:29 pm

I was not too clear with my comments in an earlier post it appears. I am certain that a good programmer could write an app in a few minutes to do the calculations, but do we really want flight crews calculating what should be design issues while descending and doing circling approaches like this one. For some of these approaches they are visual approaches masquerading as circling approaches to improve traffic flow in relatively good weather conditions. But they are a bit of a trap for crews that may not be regularly operating into these airports and who are not doing circling approaches every day. Given that the circling approach training that most crews receive these days is not very through as far as I can tell they should be visual approaches with higher weather limits. As for more circling approach training, right now the standards for approval of Flight Simulators do not allow very complex visual circling approaches to be done due to horizontal field of view limitations in most simulator visual systems as the landing runway must stay in view throughout the maneuver to get it approved for training. The only training one will get in a simulator where most pilots train these days is typically a simple circling approach with a 90 degree turn onto final approach not a complex approach like this one.
 
ClimberTroy
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 6:51 pm

hitower3 wrote:
ClimberTroy wrote:
I joined this forum to have a question answered, I don't have any aviation knowledge but was on the golf course that day and was about 100 yards from impact. Let me start by stating I noticed the sound was lower that the rest of the jets that day, I turned to locate the jet and then heard the sound change from a normal jet sound to a high pitched "squeal", a sound that is normal in movies when the decent become extreme. AS ring doorbell shows impact and it was a very steep angle. About 3 seconds or so of hearing that sound I heard impact and then then explosion. We were at the site within a few minutes. In hearing the radio contact there was no indication of a problems, and roughly 10 seconds after the last contact the tower saw smoke .... on the ground were two Cirrus Aviation "employees/pilots. Seems very weird they could be on site so quickly, ideas?


Dear ClimberTroy,

Did you consider to share your observations with the FAA? https://www.faa.gov/contact/
Even though the data recorders will provide valuable information, eye witness reports may be of interest for them too.

Kind regards,
Hendric

I didn't actually witness the plane crash, it was the sound of what I heard.of the engines and their change and hearing the impact. There's other's on another fairway that I'm quite certain had seen the entire incident. There's a "ring" video as well.
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 9:52 pm

GalaxyFlyer wrote:
There’s no way the FAA or PANS-OPS could produce a circling approach that includes a constant descent path to the threshold—too many variables. True, RNP AR could be the fix, but the FAA has made it near impossible for non-airline operators to get approval.


It is an ICAO and FAA requirement to be able to do so, eg 91.175 "The aircraft is continuously in a position from which a descent to a landing on the intended runway can be made at a normal rate of descent using normal maneuvers". Circling is only permitted onto RW11 for that approach anyway (CAT C). They would have been 1800 ft above the runway, if they were back at 140 kts and around 35 deg AOB from a downwind position to final (to remain within 3.2 nm with the higher TAS), that turn would be around 5 track nm, plus around another 1 nm on downwind would give them around 6 nm. They could have done a constant descent of around 300 ft/nm. Difference with PAN-OPS is you could have done it with 25 deg AOB to remain within 4.2 nm however the minima would likely have been higher. Doubtful they had the visibility to use the full circling area.

However in this case they commenced maneuvering outside the circling area and tracked for an oblique base to RW11, and they appear to have contacted the ground not far from the extended centerline of 11, they would have had around 8 track nm with their maneuvering if they had completed the turn and landed. Given the reported visibility at the time, I am not sure what runway environment (i.e., the runway threshold or approach lighting aids or other markings identifiable with the runway) they had in sight.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 10:11 pm

While I don’t dispute your geometry or 91.175; US TERPS has plenty of airports, usually, but exclusively, mountainous terrain where the visibility required is 3SM and MDA HAA exceeds 2,000’. Take a look at KEGE and KASE, for two 121-served airports where likely flown descent gradients exceed 400’/nm. You have to use very high rates of descent to get into stable criteria at 1,000’ AFE.

The solution here was either the 11 or 20 runways out of straight in approaches. Circling is authorized out of KTRK 20 approach for CAT C planes, must be day and must not maneuver in the quadrant bounded by south of 11/29 and east of 02/20.
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 10:40 pm

GalaxyFlyer wrote:
Take a look at KEGE and KASE, for two 121-served airports where likely flown descent gradients exceed 400’/nm.


That is the reason why they are circling, they exceed the maximum descent angle for straight in. Fully configured 400'/nm is very possible, it is not something you can afford to be behind on.

GalaxyFlyer wrote:
Circling is authorized out of KTRK 20 approach for CAT C planes, must be day and must not maneuver in the quadrant bounded by south of 11/29 and east of 02/20.


Only to RW11.
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Tue Aug 03, 2021 11:07 pm

Please show me a chart where circling is prohibited to 02, 20, or 29. Off of the inbound course, one could circle on the north side to either 11 or 29 or circle on the west side of 02/20 to land on 02. All of those patterns avoid circling south of 11/29 AND east of 02/20. It’s AND not OR. There’s a terrain map over on PPW showing the “no circle” area for Cat C.

https://www.flickr.com/photos/193677323 ... res/umC3cM
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Wed Aug 04, 2021 2:17 pm

GalaxyFlyer wrote:
Please show me a chart where circling is prohibited to 02, 20, or 29. Off of the inbound course, one could circle on the north side to either 11 or 29 or circle on the west side of 02/20 to land on 02. All of those patterns avoid circling south of 11/29 AND east of 02/20. It’s AND not OR. There’s a terrain map over on PPW showing the “no circle” area for Cat C.

https://www.flickr.com/photos/193677323 ... res/umC3cM


I am not a member of PPW.

I read the note to mean that cat C circling only available to the NW, the way circling is depicted on charts varies a lot around the world, a more common way to have that written would have been no circling to the SE of 20/29, I read it as circling only permitted to the NW.

I have seen those style of charts before on the FAA website, I cannot remember how I got in there. Do you know where I can find them again ?
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
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adv40624
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Re: Bombardier CL 600 down near Truckee, California

Wed Aug 04, 2021 8:19 pm

One of the passengers killed on this flight was John Dunn, Co-Founder of a $1.6B Real Estate Investment Firm.

https://www.msn.com/en-us/money/news/jo ... hp&pc=U531
 
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zeke
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 23, 2021 11:32 pm

The NTSB preliminary report for this accident (WPR21FA286) has been released. Nothing in there I could see that adds to what we did not already know.

https://truckeetahoeairport.com/documen ... report-pdf
“Don't be a show-off. Never be too proud to turn back. There are old pilots and bold pilots, but no old, bold pilots.” E. Hamilton Lee, 1949
 
GalaxyFlyer
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Re: Bombardier CL 600 down near Truckee, California

Mon Aug 23, 2021 11:46 pm

FAA TERPS Manual, Chap 2, pg 2-57 onward for restricted circling. I agree easily confused and poorly worded, but it’s the FAA. They crossed the extended centerline 45 degrees off final course.

https://www.faa.gov/documentLibrary/med ... pdf#page89

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