Western727 wrote:

DUSdude wrote:

FlyingViking wrote:

The ABC13 feed has a very short view from the right rear down. I think I can just catch the trailing edge of the right wing. Looks like flaps were extended.
https://abc13.com/plane-crash-katy-toda ... /11143371/

I don't see flaps in that footage from the rear angle. I only see the flap track fairings or whatever they are called under the wing. The MD80s have a pretty massive leading edge slat that would be quite prominent and would reflect a lot of light as it is unpainted aluminum. I'm not seeing that in any footage either. So the plane looks not configured for takeoff to me. Other question is why the thrust reversers are stowed.

The TE flaps and LE slats look extended to me. The LE looks too "thick" from the front to be clean. Further, on the taxi out segment at 1:31 we see the port spoilers going up as part of the usual pre-takeoff check, and the TE flaps are clearly down at that point, indicated by the angle of the TE flap vs the fuselage with the stowed position on the fuselage exposed. The slats look extended at that point as well, evidenced by the shinier part of the upper LE of the wings that gets exposed when the slats are out.

wjcandee wrote:

Interesting, though not necessarily indicative of anything, that they brought a mechanic along for the ride.

1. While taxiing from the terminal, a momentary rising of spoilers seems to indicate a "Flight Control Check" was accomplished,
2. A flight control check is also a "freedom of movement" check. Obviously in aircraft where the position of the flight controls can also be checked (either visually or by EFIS Flight Control page), it serves the purpose of verifying operation of the system, but it also verifies lack of binding, whether mechanically or due to, say, ice build-up.
3. The observed puff of smoke occurs at the beginning of the takeoff roll and if any significant thrust reduction had occurred, it would be both negligent on both pilots to not note it - especially the PF due to having to counter that with steering/yaw control, which...
4. ...is unlikely since:
   1. The tracks appear to be pretty much on center line at the end of the runway, not what might be expected with an engine failure, and
   2. Ignoring an asymmetric thrust situation until well beyond V1 is also unlikely by a professional crew.
5. By process of elimination, and also evidenced by an abort that exceeded the aircraft's ability to stop within the required runway distance (thrust reversers are not required for balanced field calculations) as well as early passenger comments, we can be pretty sure this abort happened well after V1 and likely due to the inability of the crew to rotate the nose [high enough] to generate enough lift in the aircraft's configuration to leave the runway and therefore boils down to:
   1. A wing improperly configured for the conditions, or
   2. Horizontal Stab configuration (trim and/or malfunction) incapable of rotating the nose high enough.

OldB747Driver wrote:

Obviously in aircraft where the position of the flight controls can also be checked (either visually or by EFIS Flight Control page), it serves the purpose of verifying operation of the system, but it also verifies lack of binding, whether mechanically or due to, say, ice build-up.

wjcandee wrote:

cat3appr50 wrote:

Not sure how the aircraft proceeded to 150 kn GS without liftoff, but in any case with normal flaps and takeoff thrust and calc. TOW it would have lifted off way before 150 kn GS (est. 120 KN +/-). Possibly inadequate flaps setting may have occurred, stabilizer trim way off relative to what was needed, or a jammed elevator situation. One engine failure being asserted as a potential cause...then how did they get to 150 kn GS and not have rejected the takeoff way before this point if that occurred?

Agreed. I think the puff of smoke is going to be a red herring. The passenger who spoke to the media did not mention anything about the pilots saying it wouldn't accelerate. Instead, she said that the pilots told her the one pilot tried to rotate and it wouldn't, so the other tried, and when he couldn't get it to rotate, they aborted. That could explain the 150; the acceleration of the aircraft continued as they attempted to rotate her, maybe taking longer than optimal to call a high-speed abort. That also may explain why the tire marks seem to come a lot further down the pavement than one would expect for an abort just after V1.

GalaxyFlyer wrote:

Am I getting this right, this is the first flight after being on the ground for ten months?

DL_Mech wrote:

The DC-9/MD-80 does not have an indicator showing flight control position (other than flaps and a spoiler deployed light/message). Even if an indicator was provided , the tab driven flight controls would not show movement until there was airflow across the surface.

A fight control check of the elevators would feel normal even if maintenance left a screwdriver jammed in the elevators.

OldB747Driver wrote:

I know its been awhile since Delta had the MD's but maybe you would have some info on whether a nose down trim setting could completely override any nose-up control input? Or what procedure would be used by a flight crew to verify that the elevator surfaces moved freely after start-up?

wjcandee wrote:

How interesting that NTSB says December 2020, when ADSBExchange shows all sorts of data from a trip southwest across Mexico to points unknown in April. Out on April 21, return on April 26, each way with a stop in Nuevo Laredo. Transponder lit up numerous times in the two weeks before this flight, but always on the ground. Presumably preparing for this trip.

nm2582 wrote:

wjcandee wrote:

How interesting that NTSB says December 2020, when ADSBExchange shows all sorts of data from a trip southwest across Mexico to points unknown in April. Out on April 21, return on April 26, each way with a stop in Nuevo Laredo. Transponder lit up numerous times in the two weeks before this flight, but always on the ground. Presumably preparing for this trip.

Makes one wonder if the logbooks for the aircraft are missing that flight.

DL_Mech wrote:

I’m not a pilot, but I would hope Douglas would not design a plane that would not rotate due to a poorly trimmed stabilizer. Hopefully someone will have some info.

I am surprised at the amount of 737NGs without any surface position indicator. I’ve seen them on military versions and a few foreign operators, but there are a lot of planes out there without an indicator. I guess standard operating procedure is free moving flight controls during pre-flight checks?

1. A horizontal stabilizer/elevator issue, followed by...
2. "Something" pushing the power up on that number 2 engine, with the most likely candidate being an autothrottle that re-initiated power after manually pulled back by the PF, thereby not only negating the efforts to bring the aircraft to a stop on the runway surface, but also not allowing the thrust reversers to deploy (engines not at an idle setting).

trnswrld wrote:

IF it is true that the aircraft had not been flown in 10 months, is that normal for its first flight to be done with passengers? I’ll be honest if I boarded an aircraft and they told me this thing hasn’t left the ground in nearly a year I’d be a little concerned.

trnswrld wrote:

IF it is true that the aircraft had not been flown in 10 months, is that normal for its first flight to be done with passengers? I’ll be honest if I boarded an aircraft and they told me this thing hasn’t left the ground in nearly a year I’d be a little concerned.

IAHFLYR wrote:

5. If that puff of smoke was indeed a compressor stall why continue the takeoff?

GalaxyFlyer wrote:

Using contract pilots is already being investigated courtesy of the Tahoe accident. Lots of issues there—vetting, training standards, CRM, knowledge of the operations. An MD-87 looks cheap to buy, but the cost of operating is likely beyond the airline’s costs, it’s still an expensive plane. A $60 million bizjet costs about 10% or $6 million a year to operate. Buy a 10-year old plane of the same model, it’ll cost $6 million plus some—no longer under warranty, more wear and tear to fix, etc. 200 hours a year on an MD-87 could easily cost $3 million a year.

airplanedriver6 wrote:

Good question, but in fairness not all compressor stalls are noticeable from the flight deck.

ryanov wrote:

The Ameristar accident would seem to prove that that's not true, if I remember the facts correctly. It seems unlikely to me that this is the exact same cause, so soon after and when it has been studied closely, but it's just an example.

airplanedriver6 wrote:

IAHFLYR wrote:

5. If that puff of smoke was indeed a compressor stall why continue the takeoff?

Good question, but in fairness not all compressor stalls are noticeable from the flight deck.

nm2582 wrote:

The aircraft achieved an airspeed where rotation and liftoff should have been possible. I am still suspicious about engine #1 (puff of smoke, lack of burn marks behind it at the crash site) but it seems most likely that if #1 did have a problem the crew became aware of, it must have happened after V1. An engine failure after V1 could have increased the workload and/or been a distraction from the RTO efforts/decision making.

GalaxyFlyer wrote:

An engine failure recognized after V1 should have gone airborne, not result in a RTO.

FlyingViking wrote:

It absolutely should, but that didn't happen with Garuda in Japan in 1996. Another abort past V1 was Spantax in Malaga in 1982 (tire failure). Both of them disasterous.

investigators found that the airplane’s left and right elevators were jammed in a trailing edge down position; neither elevator could be moved when manipulated by hand.

​Both inboard actuating cranks for both elevator’s geared tabs were bent outboard, and their respective links were bent. Both actuating cranks and links were found locked in an overcenter position beyond their normal range of travel.

Preliminary data from the airplane’s FDR showed that both elevators were positioned at approximately 18º to 19º trailing edge down when the flight crew applied power and remained there during taxi. Upon reaching rotation speed, the recorded elevator positions split, but neither moved to a trailing edge up position. The airplane reached a maximum speed of about 158 knots before decelerating. The operating parameters appeared normal on both engines and matched throughout the recording.

The damage observed to the left and right elevator geared tab input rod links is similar to the damage found during an investigation of a Boeing MD-83​, which crashed after a rejected takeoff on March 8, 2017.