Maroc 737 in loss-of-lift incident at FRA
Join Date: Apr 2012
Location: In Space
Posts: 683
Likes: 0
Received 0 Likes
on
0 Posts
My guess is a performance error. Clearly in the video a low flap setting was used (flaps 1)so my guess is that performance was based on a higher flap setting but the pilots used a low flap setting instead, either intentional or not. Which resulted in rotating earlier and nearly tail striking. The airport is Frankfurt which has two very long runways, so flaps 1 could of easily been used (if performance allowed).
Crikey, that's not flash!
Join Date: Jan 2006
Location: Between a rock and a hard place
Posts: 1,267
Likes: 0
Received 0 Likes
on
0 Posts
I am curious what the trim was set to. To me seems like a rather short take off roll for a (my assumption) reduced thrust take off on a long runway.
Join Date: Nov 2001
Location: S51 30 W060 10.
Posts: 197
Likes: 0
Received 0 Likes
on
0 Posts
wrong derate maybe...incorrect flap setting. Had it been a 738 we woulda seen a show of sparks at the tail.
Another possibility is thrust setting and V speeds calculated for a wrong takeoff weight. ZFW entered prior to refueling, calculations made on a ZFW + fuel remaining from previous flight. Long flight ahead, 10-15 tons of fuel not accounted for.....otherwise it's real hard to not become airborne. Any airplane with the correct thurst setting and a smooth rotation rate, like the one in the vid, can be rotated 10 knots prior to Vr and it will fly. This sure was a combination of "wrongs".
Another possibility is thrust setting and V speeds calculated for a wrong takeoff weight. ZFW entered prior to refueling, calculations made on a ZFW + fuel remaining from previous flight. Long flight ahead, 10-15 tons of fuel not accounted for.....otherwise it's real hard to not become airborne. Any airplane with the correct thurst setting and a smooth rotation rate, like the one in the vid, can be rotated 10 knots prior to Vr and it will fly. This sure was a combination of "wrongs".
Last edited by sudden Winds; 25th Aug 2016 at 13:19. Reason: :)
Join Date: Jun 1996
Location: Check with Ops
Posts: 741
Likes: 0
Received 0 Likes
on
0 Posts
Well, he's definitely got at least Flap 1 set because you can see the slats extended. I cannot recall if Flap 1 is a takeoff flap setting for the 737 but, if it is not, they would have got a config warning on applying thrust. My quarterbacking would guess at wrong weights in the FMC (ZFW entered into the GWT field etc) giving the wrong speeds on the speed tape. I'm very glad the PF did the right thing when confronted with a lack of lift and gave the wings a few more drops of IAS before having another go when a bigger arrow of upward energy was formed. He didn't panic and try and stop, so I reckon he made a good job out of a bad situation, even if they did (maybe) cause that problem in the first place. Incorrect FMC entries have been around for quite some time now and I'm sure there will be more but let's hope better data entry procedures will mitigate against too many occurring.
Join Date: Mar 2006
Location: England
Posts: 115
Likes: 0
Received 0 Likes
on
0 Posts
Looks like a zero fuel weight error, which can happen very easily, especially if you're rushing. However, a 1 tonne error only equates to around 1 knot on the speeds so it would have had to be a big discrepancy. The PF did a good job though IMHO as a tail strike was on the cards.
RAM Response...
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???
"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???
