Royal Air Maroc B737 rotates well before Vr

Flyingabout · Thu Aug 25, 2016 10:13 am

https://www.youtube.com/watch?v=Kle80KB_s3I

N14AZ · Thu Aug 25, 2016 10:17 am

Nice Video, obviously taken in Frankfurt, the RAM 737 is taking off on runway 18...

pvjin · Thu Aug 25, 2016 10:42 am

I'm not so sure whether the aircraft rotates before V1, but definitely before VR.

blackbox67 · Thu Aug 25, 2016 10:48 am

Slats were out as normal. Premature rotation nearly lead to a tailstrike. Perhaps pilots inserted wrong FMC data. Thankfully runway 18 at FRA is long enough...have trust in your thrust.

Dominion301 · Thu Aug 25, 2016 12:56 pm

Good thing it was a 73G and not a 738 or else a tailstrike would have almost certainly occurred.

FriscoHeavy · Thu Aug 25, 2016 1:20 pm

This is very interesting. Would love to know exactly what happened here and why he tried to rotate at the speed he was. One would think that either he input the flight data incorrectly OR the plane was actually much heavier than assumed.

Very lucky they had enough runway for this not to be an issue. A lot of places and with a larger aircraft, this could have been a major disaster.

jetwet1 · Thu Aug 25, 2016 2:59 pm

pvjin wrote:
I'm not so sure whether the aircraft rotates before V1, but definitely before VR.

A question for the pilots on here.

I would think that if you are the Captain of the aircraft, acting as the PF or PNF, you would have a ballpark idea of what the VR should be, even without the aircraft or paperwork telling you ? So if you are accelerating down the runway and the PNF calls VR at say 120 knots and in your head you know that is way to slow, what do you do ?

rrlopes · Thu Aug 25, 2016 3:38 pm

jetwet1 wrote:
pvjin wrote:
I'm not so sure whether the aircraft rotates before V1, but definitely before VR.

A question for the pilots on here.

Not a pilot, but worked as a Flight Ops Engineer for many years, so I'll give my input.

It's difficult because VR is not the only speed pilots will have to deal with during takeoff, but also V1, V2 and VFS. All speeds will vary not only with the weight of the aircraft, but also flap setting, airport elevation, atmospheric pressure and temperature. V1 might vary even more, considering thrust settings, runway length and obstacle clearance requirements. Something really obvious might be possible to notice, but it's not as easy as it seems.

Having said all that, the time the pilot might notice a discrepancy is when inserting the speeds in FMC, not during the takeoff run. It's not a surprise for him when he reaches V1, VR and V2, he'll know what the speeds are before the run starts.

Just my 2 cents, hope it helps.

Armodeen · Thu Aug 25, 2016 8:29 pm

Wow. When it doesn't get airborne they raise the nose further, very nearly striking the tail and getting briefly off the ground. Once the gear contacts again they finally lower the nose and pick up more speed before rotating again.

As another poster said, in another place with another aircraft, a major incident could have occurred.

BALandorLivery · Thu Aug 25, 2016 8:54 pm

Clearly a grave mistake took place.

It could have been disastrous and a reject at that point could have been messy too.

Whatever happened, be sure of this: the RECOVERY was first class airmanship.

Nose lowered
Speed allowed to increase
Tail not scraped
Aircraft airborne

'Twas a close call though

I've departed on that runway a few times and the trees beyond the runway are looming right there at the end.

ikolkyo · Thu Aug 25, 2016 9:06 pm

I'd love to hear what was said in the cockpit.

Blankbarcode · Thu Aug 25, 2016 9:28 pm

Almost panicked when I saw the news headline, "Royal Air Maroc 737 Stalls on Takeoff". I was so absoutely sure an accident had occured.
Glad to know everything went alright though, but I am curious as to what could have caused the cofusion. Incorrect V-speed settings?

LAX772LR · Thu Aug 25, 2016 9:54 pm

Wouldn't it be more accurate to say that aircraft's Vr was before Vmu?

william · Thu Aug 25, 2016 11:27 pm

ikolkyo wrote:
I'd love to hear what was said in the cockpit.

Probably censored.

barney captain · Thu Aug 25, 2016 11:48 pm

A few thoughts -

Yes, you can guesstimate what the V speeds will be for any given weight. While V1 will be lower on shorter runways, VR and V2 usually fall within a familiar range for a the weight shown. Here's the kicker - is the weight listed correct? There have been any number of loading errors wrt fuel/freight/pax (yes, even pax) with the final weight was missing some very big numbers.

Yes, they were lucky the weren't at MDW. Even still, I have always maintained that - given adequate runway - many loading and performance errors can be mitigated by simply allowing the aircraft to fly itself off of the runway when she's ready. Pulling the a/c into the air is rarely a good idea imo. "Pull and pray" as it were.

It's obviously difficult to tell from the video, but I wonder if full thrust was applied at any point. The -700 is wonderfully overpowered and unless that a/c was near MTOW, there should have been enough residual thrust to provide a more difinitive rate of climb than settling back onto the runway.

An767 · Thu Aug 25, 2016 11:56 pm

Bet the passengers though "WTF is going on" not your normal takeoff and would have been a bit unnerving for some
AN767

AA737-823 · Fri Aug 26, 2016 12:12 am

Let's not get too dramatic, folks- this is a.net, the site for enthusiasts, not CNN, the site for psychopathic alarmists.
That said, something clearly wasn't quite right.
I'm wondering whether, judging by the significant wind noise in the recording, they encountered a shift in wind speed or direction at or near their geographic point of rotation, which gave them a sudden decrease in airspeed. It would explain the over-rotation, and subsequent leap into ground effect, and the settling back. However, the rotation does seem to be a bit early in the takeoff roll, but it's hard to judge that, since there are too many variables that we can't know unless we were in the flight deck.

BALandorLivery wrote:
Clearly a grave mistake took place.

Whatever happened, be sure of this: the RECOVERY was first class airmanship.

Nose lowered
Speed allowed to increase
Tail not scraped
Aircraft airborne

Yes, I think the recovery was handled calmly. Certainly an interesting day for someone. And now, through the miracles of technology, millions of people can find out about an event that would previously have been simply a "lesson learned."

TWA772LR · Fri Aug 26, 2016 2:10 am

Perhaps it was a reduced thrust take off?

TS-IOR · Fri Aug 26, 2016 4:17 am

According to RAM crew was cleared for take-off and been advised of possible wake turbulence from the heavy TK landing 07. Early rotation was to avoid the wake turbulence effect. I personally didn't believe a clue in that. Rotation point was well south of the 07 path and thus minor effect and if true pilots had only to wait for a minute or so and then depart.

mitchell747 · Fri Aug 26, 2016 4:32 am

that was a very bad take off!!!. it looked like it missed vfto for sure. why was that suck a bad landing, did the pilot get the take off speed wrong?

AR385 · Fri Aug 26, 2016 4:33 am

It seems very similar to this occurrence:

http://avherald.com/h?article=460db38a&opt=0

Although here the aircraft was a write-off.

CrimsonNL · Fri Aug 26, 2016 5:12 am

TS-IOR wrote:
According to RAM crew was cleared for take-off and been advised of possible wake turbulence from the heavy TK landing 07. Early rotation was to avoid the wake turbulence effect. I personally didn't believe a clue in that. Rotation point was well south of the 07 path and thus minor effect and if true pilots had only to wait for a minute or so and then depart.

I don't know whats more worrying, the incident itself of the "official communication" from RAM which is obviously just a cover-up. Not that I had expected an honest statement from RAM.. A simple "we are looking into this incident" would have sufficed but they are unable to admit their mistakes it seems.

Martijn

cbphoto · Fri Aug 26, 2016 5:18 am

TS-IOR wrote:
According to RAM crew was cleared for take-off and been advised of possible wake turbulence from the heavy TK landing 07. Early rotation was to avoid the wake turbulence effect. I personally didn't believe a clue in that. Rotation point was well south of the 07 path and thus minor effect and if true pilots had only to wait for a minute or so and then depart.

This is a scary statement, and I really would like to know what it even means? Where they so focused on the wake turbulence, that they decided to rotate early, as in before Vr speed?

Also, everyone on here is mentioning speeds and all, but an out of CG trim setting would cause the same affect, only it would be uncommanded by the flight crew. Either way, it could have ended up being bad.

flyingbird · Fri Aug 26, 2016 5:48 am

TS-IOR wrote:
According to RAM crew was cleared for take-off and been advised of possible wake turbulence from the heavy TK landing 07. Early rotation was to avoid the wake turbulence effect. I personally didn't believe a clue in that. Rotation point was well south of the 07 path and thus minor effect and if true pilots had only to wait for a minute or so and then depart.

Aesma · Fri Aug 26, 2016 10:22 am

Does this technique of "rotating early to avoid wake turbulence" actually exist ? Do they mean making the take-off run shorter ? Which would imply full thrust instead of derated for example.

My instinct would tell me that if you're going to fly through turbulence you'd rather have extra speed than the opposite (not talking about cruise).

b747400erf · Fri Aug 26, 2016 10:37 am

Why would you rotate earlier to avoid when you can continue down the runway and be clear of the wake? Rotating "early" would only be removing the de-rated thrust setting. And rotating early puts you right in the path of the landing aircraft.

PeterB · Fri Aug 26, 2016 11:05 am

1) Why didn't the pilot reject the take-off?
2) In the video, the flap configuration looks a bit flat for take-off. Am I right or do I see it wrong?

b747400erf · Fri Aug 26, 2016 11:45 am

PeterB wrote:
1) Why didn't the pilot reject the take-off?
2) In the video, the flap configuration looks a bit flat for take-off. Am I right or do I see it wrong?

Some airlines use flaps 1 for take off if light and long runway.

FriscoHeavy · Fri Aug 26, 2016 1:01 pm

Imagine if this had occurred at SNA or MDW. Scary to think about....

migair54 · Fri Aug 26, 2016 1:16 pm

Aesma wrote:
Does this technique of "rotating early to avoid wake turbulence" actually exist ? Do they mean making the take-off run shorter ? Which would imply full thrust instead of derated for example.

My instinct would tell me that if you're going to fly through turbulence you'd rather have extra speed than the opposite (not talking about cruise).

No, you must rotate at your point, as you mention full thrust is a good idea, the technique to avoid a preceding aircraft wake is to fly upwind and up the preceding plane, if you can't do that it's better to wait on ground for a couple of minutes then depart.

I think they insert wrong data in the FMC so the FMS calculate wrong speeds, it's not the first time that happen, remember EK in MEL and some others. Shit in - shit out situation.

PeterB wrote:
1) Why didn't the pilot reject the take-off?
2) In the video, the flap configuration looks a bit flat for take-off. Am I right or do I see it wrong?

Reject a take off above V1 is a very dangerous business, only if the plane is unable to fly I will consider that, but in this case I think the procedure was correct, lower nose, get speed and I guess they press TO/GA to get full power.

The flap is normal, I think it's flap 5 take off.

TWA772LR wrote:
Perhaps it was a reduced thrust take off?

Most of the take offs in non contaminated runways are derated take offs, it's use to preserve the engine life.

jetwet1 · Fri Aug 26, 2016 2:02 pm

AR385 wrote:
It seems very similar to this occurrence:

http://avherald.com/h?article=460db38a&opt=0

Although here the aircraft was a write-off.

Somebody on there actually came up with a better way of questioning what was going on than I did, to quote :

"Would Vr ever be as low as 118 KIAS for a 767, regardless of load? Would it ever be that low for a "normal" flight in a 767?

If the answer to either of the above is "no", then what about the sanity checks that should be in the software. As a software designer and programmer, I would always require any mission-critical figures entered externally to be checked for "reasonableness" as well as being cross-checked where possible against other entries."

That is what I was trying to say, in my line of work I deal with numbers all day, let's say X=Y +/- 5%, if it doesn't it jumps off the screen at me as wrong or needs to be investigated, when the pilot inputs the figures into the FMC, in the back of their mind they should have a figure, somewhere around 150-160 knots, a figure of 120 is on the sheet, shouldn't that make the pilot go "huh?" or am I wrong ?

euroflyer · Fri Aug 26, 2016 2:03 pm

TS-IOR wrote:
According to RAM crew was cleared for take-off and been advised of possible wake turbulence from the heavy TK landing 07. Early rotation was to avoid the wake turbulence effect. I personally didn't believe a clue in that. Rotation point was well south of the 07 path and thus minor effect and if true pilots had only to wait for a minute or so and then depart.

Can you provide with the source please ?

StTim · Fri Aug 26, 2016 2:11 pm

This was something I try and get kids today to do in my line of work - have an idea of the answer so that when the spreadsheet (or what ever) spits out an answer they have some immediate concept of whether it is correct or not. It is amazing how many just trust the answer as it has come out of a computer.

tistpaa727 · Fri Aug 26, 2016 4:06 pm

StTim wrote:
This was something I try and get kids today to do in my line of work - have an idea of the answer so that when the spreadsheet (or what ever) spits out an answer they have some immediate concept of whether it is correct or not. It is amazing how many just trust the answer as it has come out of a computer.

I'm glad you are trying to teach this. In my line of work, enterprise software, we find (generally) the younger buyers and users blindly trust the technology to provide the correct answers. They don't care how the answer was derived, just that they were provided an answer and therefor marching orders. Sad really.

Not saying that has any impact here just that your comment made me think of this trend we see.

tb727 · Sat Aug 27, 2016 2:18 am

TWA772LR wrote:
Perhaps it was a reduced thrust take off?

I've watched and listened close a few times now, I hear them push the thrust up to the initial stabilization setting(whatever that is for that 737) but I really can't tell if it's increased much more. Once they lowered the nose and figured it out and maybe set the proper thrust it seemed to fly heck of a lot better.

It seems like a strange thought but I guess I applaud them for continuing the takeoff instead of doing a high speed reject.

BoeingVista · Sat Aug 27, 2016 8:43 am

tb727 wrote:
TWA772LR wrote:
Perhaps it was a reduced thrust take off?

I've watched and listened close a few times now, I hear them push the thrust up to the initial stabilization setting(whatever that is for that 737) but I really can't tell if it's increased much more. Once they lowered the nose and figured it out and maybe set the proper thrust it seemed to fly heck of a lot better.

It seems like a strange thought but I guess I applaud them for continuing the takeoff instead of doing a high speed reject.

Its clearly a very odd sequence of events.. my bet would be on bad CoG

From my obervation the nose wheel seems to come up at 40-42 secs hovers up so pilot decides to rotate, but it won't unstick so the rotates again at 49 which does unstick but aircraft remains in ground effect and comes back down to the runway, which is where the pilot makes his smart decision to keep nose down and gain speed before rotation number 3 which gets her flying.

Nose wheel coming up so early in the roll without obvious pilot input to me says a CoG loading error.

sandyb123 · Sat Aug 27, 2016 10:40 am

Note that all the window blinds are shut so could this actually be the opposite, the aircraft was empty hence the early rotation based more on the aircrafts natural want to get Airborne rather than anything that the pilots actually input?

IIRC (and certainly based on anything small / tiny I have flown) the aircraft is designed to go skyward and if you don't put in a little bit of negative effect that can result in an early rotation.

sandyb123

fotoflyer71 · Sat Aug 27, 2016 12:59 pm

Looks to me like rotation was due to elevator deflection (ie pilot input) not stab trim setting.

TS-IOR · Sat Aug 27, 2016 1:45 pm

To read the full official RAM statement please check their Facebook page Royal Air Maroc. It's in French. They may have added one in English now.

AirlineCritic · Sat Aug 27, 2016 9:04 pm

Does look very scary. Be interested in reading the full report.... if one ever is forthcoming...

wezgulf3 · Tue Aug 30, 2016 12:33 pm

No investigation into this (somehow!)

https://www.flightglobal.com/news/articles/german-bfu-no-probe-into-ram-737-take-off-incident-428886/

Wes...

D L X · Tue Aug 30, 2016 2:49 pm

AR385 wrote:
It seems very similar to this occurrence:

http://avherald.com/h?article=460db38a&opt=0

Although here the aircraft was a write-off.

Reading that report, it sounds like the crew had intended to continue flying towards Mexico City! And then you look at the pieces of tail hanging off the empannage....

That could have been a disaster many times.

rcair1 · Tue Aug 30, 2016 6:03 pm

Aesma wrote:
Does this technique of "rotating early to avoid wake turbulence" actually exist ? Do they mean making the take-off run shorter ? Which would imply full thrust instead of derated for example.

My instinct would tell me that if you're going to fly through turbulence you'd rather have extra speed than the opposite (not talking about cruise).

While you cannot "rotate early", meaning you cannot rotate before the a/c reaches the correct speed, but you can plan your takeoff to rotate/lift off at a location earlier (before) on the runway than the aircraft whose wake turbulence you are trying to avoid - if your aircraft has the performance to do so.

Wake turbulence on take-off will
- Start at the point on the runway where the aircraft lifts off, not before.
- Move down and out from that location (assuming no cross wind.)

So - the wake turbulence of an aircraft ahead of you will be below it's flight path and will not start till THEY rotate.
---
That means that, if your aircraft has the performance to do so, you can plan your takeoff to lift off before their lift off point and stay above their climb path.

Not sayin' that this has anything to do with what we saw in the video...

D L X · Tue Aug 30, 2016 6:11 pm

rcair1 wrote:

So - the wake turbulence of an aircraft ahead of you will be below it's flight path and will not start till THEY rotate.
---
That means that, if your aircraft has the performance to do so, you can plan your takeoff to lift off before their lift off point and stay above their climb path.

How long does wake turbulence from a preceding aircraft last? (At least on or near the takeoff runway?)

N14AZ · Wed Aug 31, 2016 12:12 pm

I really like the title The Aviation Herald has Chosen for this incident:

Incident: Royal Maroc B737 at Frankfurt on Jul 23rd 2016, three takeoffs for the price of one

http://avherald.com/h?article=49d159fc&opt=0
:-)

United_fan · Wed Aug 31, 2016 12:17 pm

If that was EYW,they'd be in the Ocean.

Clipper101 · Wed Aug 31, 2016 12:52 pm

Once I travelling in an A319 & there was a B744 taking off ahead of us, I noticed our A319 climb was very rapid & steep with the engines roar seemed as if they are giving every power they could. I gathered the pilot was trying to climb above the wake turbulence generated from the departing B744.

Still I do not understand for such smaller aircraft departing behind heavier ones why higher flap settings are not selected for takeoff to guarantee earlier rotation velocities?!

N14AZ · Wed Aug 31, 2016 1:14 pm

Clipper101 wrote:
Still I do not understand for such smaller aircraft departing behind heavier ones why higher flap settings are not selected for takeoff to guarantee earlier rotation velocities?!

I think there is a misunderstanding concerning this potential wake turbulence avoidance:

TS-IOR wrote:
According to RAM crew was cleared for take-off and been advised of possible wake turbulence from the heavy TK landing 07. Early rotation was to avoid the wake turbulence effect. I personally didn't believe a clue in that. Rotation point was well south of the 07 path and thus minor effect and if true pilots had only to wait for a minute or so and then depart.

As TS-IOR wrote, the claim is that the 737 pilots made this early rotation to avoid wake turbulence effect. BUT the TK A330 landed on another runway (you can see it at the beginning of the video), the two runways are almost perpendicular to each other (runway 18, from which the B737 took off, is in the background of the picture below.

PanHAM · Wed Aug 31, 2016 1:30 pm

Runway 18 is diagonal from the three other runways and starts about where 07C is, I have been a passenger on flights starting on 18 many times and never experienced that the take off was bumpy because of crossing traffic. In Peak times aircraft land on 07R (like the TK A330) and on 07 while take Offs are on 07C and 18. Smaller aircraft alo taxi around the other 2 main runways and start the take off roll south of the imaginary intersection, completely Independent from traffic on the 3 parallel runways.If, in case of the RAM flight the take off roll had begun on the beginning of the 18 , the Pilot could have made a fast roll to that Point and begin the take off there.

D L X · Wed Aug 31, 2016 1:31 pm

One of the comments on avherald struck me as interesting:

What I feel is a very plausible explanation is that the vortices from the landing A330 off the right wing tip "chased" the RAM 737 during its takeoff roll and gave it a significant tailwind, rendering the pre selected V speeds (likely based on a headwind) totally insufficient. This skipped the crew until rotation, in which case they did an excellent job.

Is that possible? That the wake chased the 737 down the runway adding a tailwind component?
Looking at the photograph above of the airfield, it looks like the RAM flight started its takeoff roll from the top right corner heading towards the top left corner of the photograph, while the A330 landed on the runway coming towards us on the left. So, at the start of its roll, the 737 would have seen a headwind from the A330's wake, but maybe 900m down the 737's runway, it would have run into the center of the wake and reversed into a tailwind.

So, is it possible they were above Vr when they began rotation but below Vr when rotation was complete?

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