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Maroc 737 in loss-of-lift incident at FRA

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Maroc 737 in loss-of-lift incident at FRA

Old 26th Aug 2016, 08:49
  #41 (permalink)  
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Is this being formally investigated as an incident by the BFU?
Depends if someone ask them.
Normally a you tube video does not start an investigation.
Anyway since the length of the flight I doubt CVR will be avail.
Possibly RAM internally, but result is unlikely to go out , other of what the PR said if you ask me
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Old 26th Aug 2016, 09:14
  #42 (permalink)  
 
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Oh to be overhasty protected by PR ! People seemed overhasty to drop me in the pooh if I squeeked too loudly.
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Old 26th Aug 2016, 09:19
  #43 (permalink)  
 
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Hm. I know the -700 is often a F1 takeoff. Usually if you fly mixed fleet, you get to fly a -700 rarely. The weights and speeds always seem low. This one was a 700, was a F1 dep and on FRA's 4000m runway would probably have been an 18K with a fair bit of TASS as well. Thye rotaion was prompt so no W&B issues and probably a middle to rear trim anyway. FRA to N Africa would be 10T of fuel or so and Like a coupdl of pages earlier the most likely situation is the FZW was put in the top line of the FMC. With a good load, that would be in the low 50's and -700s do fly domestic and shorter flights at those weights, so not immediately a Gross Error item.

The crew's actions in lowering the nose carefully and waiting was safe enough, but going back to the hold for another go ant the right weight would have been safer....

I've flown a mixed fleet and with most aircraft -800s it was always a bit weird flying the sports model.
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Old 26th Aug 2016, 10:50
  #44 (permalink)  
 
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This is why you rotate slowly at higher weights,
Is that so? Couldn't find anything of that advice in the 737 FCTM for normal ops take off.. Another personal technique, maybe?
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Old 26th Aug 2016, 10:54
  #45 (permalink)  
 
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going back to the hold for another go ant the right weight would have been safer....
What? The fact that they'd already rotated meant they were at Vr, albeit the wrong one if they had the incorrect GWT. Are you suggesting that they stopped (> V1) and then went back and had another go with the correct weights entered in the FMC? Yes, the V1 that would have been displayed (assuming an incorrect weight) would have been lower than that of the correct weight but I would challenge even the most gifted mathematician in the world to work out the difference between the two, as he tries to rotate, having miraculously realised how much heavier he really was and then calculate he had the distance to stop.

IF they cocked it up and entered the wrong weight then there are lessons to be learnt but having realised the machine was not going to take to the air the PF, I believe, did a good job of increasing the speed until it would fly safely. To have stopped above V1, even if it was artificially low, would have been a mistake.....in my opinion of course.
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Old 26th Aug 2016, 12:46
  #46 (permalink)  
 
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Originally Posted by CaptainSandL View Post
Royal Air Maroc ... the Captain decided to execute a manoeuvre to gain more speed until they reached speeds that would ensure a safe take-off".
Phew! What a revolutionary concept.

Where is the successor to "Colemanballs" ?
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Old 26th Aug 2016, 16:40
  #47 (permalink)  
 
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Took a 767 out of Cancun. At rotate she didn't want to fly. So held the pitch below tail bumping attitude. She flew off 15 knots later. Spent the next 91/2 hours trying to work out why. Never found a reason so just assumed the standard baggage weight of 15 kg, was garbage.
What I now find interest is how many new pilots would just keep pulling?
Somehow the seat of pants feel is disappearing so well done the pilot of the 737.
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Old 26th Aug 2016, 17:11
  #48 (permalink)  
 
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Originally Posted by CaptainSandL View Post
Royal Air Maroc has apparently responded as follows:

"After false information was spread out regarding flight AT811 from FRA to CMN on July 23, we want to clarify that during take-off, ATC advised of possible wake turbulence from adjacent landing A330. In turn, the Captain decided to execute a manoeuvre to gain more speed until they reached speeds that would ensure a safe take-off".

Really???
As an old uncle used to say . . . " You can wish in one hand and poop in the other , see which one fills up first ! "

Air Maroc PR shows some original wishful thinking here. :-)
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Old 26th Aug 2016, 17:30
  #49 (permalink)  
 
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Clearly a Flaps 1 takeoff, however I would be completely staggered to believe a Flaps 1 takeoff would be necessary at FRA. As far as the FCTM is interpreted, Flaps 1 departures are certainly not recommendable when considering tail strike avoidance technique. Considering that it appeared to be gusty, it should probably be a no no. So, if any credit is due, the PF did pretty well to avoid the final few holes in the Swiss cheese with the technique that he or she applied. That aside, there appears to be an element of good fortune that it was FRA and not somewhere more limiting. I'll add though that I don't have -700 experience however I was under the impression that Flaps 5 is the standard takeoff setting for the 737, and certainly would be company policy if the company was flying mixed fleet.

Probably another case of incorrect application of SOP, CRM breakdown, distraction or poor checklist philosophy? Whether it be through incorrect use of OPTs or rushing through the PERF INIT page without thought (the old ZFW and GW mismatch), these type of incidents continue to crop up. Challenge, verify and respond exists as an error trap, however it's commonly disregarded when you hear what you want to hear and see what you want to see. I know I've been guilty in the past and have learned valuable lessons observing my own performance and those of others.

As for the A330 wake turbulence argument that RAM applied. No one buys it. Why would you take off, or even consider it?

Last edited by Callsign Kilo; 26th Aug 2016 at 18:09.
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Old 27th Aug 2016, 04:03
  #50 (permalink)  
 
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completely staggered to believe a Flaps 1 takeoff would be necessary at FRA.
I'll have to think about that one too!
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Old 27th Aug 2016, 06:23
  #51 (permalink)  
 
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"I was under the impression that Flaps 5 is the standard takeoff setting for the 737"

Then why does Boeing provide a Flaps 1 setting? For runways longer than 4000m ???
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Old 27th Aug 2016, 06:47
  #52 (permalink)  
 
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Reall RAM? So the PIC was told about the A330 at Vr and THEN decided to lower the nose, something that is not tested or trained or indeed approved, something he's never attempted before and get more speed?

What utter crap.....

They stuffed up, nicely recovered but a stuff up none the less...
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Old 27th Aug 2016, 08:42
  #53 (permalink)  
 
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This sums up 2016.

Everything is spin. Why not just accept that a mistake was made, admit the mistake and move on.

What is the truth anymore?
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Old 27th Aug 2016, 10:05
  #54 (permalink)  
 
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I heared on another form that that PNF's airspeed indicator had a pitot problem and was over reading. Seems plausalbe enough.
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Old 27th Aug 2016, 10:18
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Nomorecatering,

That is why we have a speed check at 80 Kts which will detect a difference between the speed indicators and allow a low speed rejected take off...
So if it is true , it means that they did not perform the check or not properly.
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Old 27th Aug 2016, 11:11
  #56 (permalink)  
 
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Dear PPRuNefolk

The RAM PR exercise is aimed at general flying public and really needs not be related to reality as long it paints company operations in positive light and info seems plausible to gal/guy who knows next to nothing about aviation. Visitors of PPRuNe, Airliners.net and similar fora represent statistically insignificant part of target public and their opinions be safely disregarded.

There are many ways one can make B737-700 behave in a way shown in the video: too early rotation, mistrimming, misloading, actual configuration lower than planned, actual weight higher than the one takeoff performance were calculated for and I'm pretty sure there are other ways I can't think of right now. As there were no damage or injury, chances are incident will be dealt with internally, within airline and any public knowledge of the investigation results will be strictly unofficial. As for potential BFU involvement, I don't expect any. Those who have read some of their recent incident reports and noticed their quality and time needed to prepare them can see that austerity measures are really working - not in the hyped way though.

700's certified takeoff flaps are 1, 25 and anything in between. If it occurs to you that you're 700 pilot and some of these are off limit to you, it's about the performance calculation package your company has bought. If one sets the wrong config but still in takeoff range, config alert will stay mum.

Tailstrike is possible on 700 but, unlike 800s, they really need to be pushed hard to perform so. WIWO700, usually it was flaps 1 takeoff with 18k derate and assumed temperature on top of everything. Personally I found 700s far more fun to fly than 800s and I yearn for the day when Southwest takes in TRDECs, Green Cards are given away liberally and EASA to FAA conversion is two days affair.

Take care

C
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Old 27th Aug 2016, 12:06
  #57 (permalink)  
 
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I was under the impression that Flaps 5 is the standard takeoff setting for the 737, and certainly would be company policy if the company was flying mixed fleet.
That depends on company policy. In my outfit, with a mix of -700 and -800s flaps 1 was the standard take off flap setting. Other companies might decide otherwise, as far as i know ryanair uses flaps 5. There are a lot of factors at work deciding those standard settings, such as average experience level, fuel saving, usual airport type used. In FRA we always used flaps 1, the runways are too long to care about a lower flap setting (1 through 25 were the normal take off flaps settings for us). Good fun to take off with an N1 of 74% or so and then getting that almighty kick in the behind at thrust reduction altitude
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Old 27th Aug 2016, 13:08
  #58 (permalink)  
 
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I suspect most companies use F1 for he -700 and F5 for the -800. As you say 18K plus a good 50+ on the TASS but the kick depends on what you set the climb thrust to. CLM-2 probably would be ok. My last outfit had an SOP of not derating climb thrust but on hte -700 we mostly still did it as the kick is pretty uncomfortable for the pax.

The thing with these things is this. What is most likely cause?

With the known gotcha of the Gross weight/ZFW in thje FMC and this flight probbly needing in the regon of 10T to go home, the result is exactly as seen. Well below actual V1 so if they'd abandoned the takeoff and slowed to vacate they'd have been only halfway down the strip... Hence my earlier comment.

Either way, it's not the first or last time these things will happen and as said, nice pitch control and a safe outcome in the end.
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Old 27th Aug 2016, 13:14
  #59 (permalink)  

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Poor airmanship, whatever. A stop would have been ok at FRA, Easily seen from the video clip of the short run before "rotation". Miscalculation of speeds likely, but whatever the cause an abort was the safe way to operate. What sort of flight safety culture does RAM have that would have allowed that type of manoeuvre I wonder?

(Perhaps the sort that claims it was nothing much, and just down to windshear from a decelerating adjacent aircraft on the ground )
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Old 27th Aug 2016, 14:55
  #60 (permalink)  
 
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Originally Posted by nomorecatering View Post
I heared on another form that that PNF's airspeed indicator had a pitot problem and was over reading. Seems plausalbe enough.
This Ci 738 reported a problem reading the speed as well IIRC:

https://www.youtube.com/watch?v=21qZPaCRSQI
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