MD-87 hits fence after takeoff from TME. All passengers survive the crash.

[Gabriel]

If you are on a legal runway length, and Vr is a typical distance beyond V1, and you adhere to RTO procedure, you should not leave the runway surface the way this one did.

Do you really expect that the pilot would start the RTO at Vr? I thought you understood human factors. After V1 the pilot has a very strong "take off" mindset, At Vr he starts to pull back, after a couple of seconds nothing happens, then he pulls up harder and harder and nothing happens then he says "ok, this is not flying, ABORT!", By then they are past V2 and a LONG distance past the V1 point. And this runway was not particularly long.

[Evan]

Do you really expect that the pilot would start the RTO at Vr? I thought you understood human factors. After V1 the pilot has a very strong "take off" mindset, At Vr he starts to pull back, after a couple of seconds nothing happens, then he pulls up harder and harder and nothing happens then he says "ok, this is not flying, ABORT!", By then they are past V2 and a LONG distance past the V1 point. And this runway was not particularly long.

I get your point on this runway, but there's too much going on here. There is an obvious issue with #1 from the beginning of the take-off roll. But that shouldn't prevent rotation at Vr. It should still fly. It looks more to me like they rejected at V1 or earlier but didn't retract thrust for some god-knows-why reason and simply applied brakes. It also looks suspiciously like two pilots flying the plane with very different intent, one intending to continue after the engine failure is detected and the other on the brakes. We've seen that before.

[Gabriel]

Two many open possibilities here. We don't know what happened with the engine at the beginning and whether the pilots knew about that. We don't know if the acceleration was normal, perhaps #1 was underperforming and that went unnoticed and they saw the end of the runway coming before they reached Vr. There are rumors that the pilot said that the plane would not rotate. This can be due to many reasons, one of them being that they were too slow. It can also be control problems, wrong trim setting, or CG more forward than calculated. Then we don't know what happened during the reject. The lack of reverser buckets in the aftermath may indicate that then never applied reverse thrust. The burn marks behind #2 may indicate that thrust remained high on #2. The lack of burn marks on #1 may indicate that #1 was not working at all. But these are not the only possible explanations. The fact that the plane was almost 2 years under maintenance is also a possible source of problems.

Again, with the pilots alive, the (burned) plane accounted for and in one place, and the 2 recorders recovered, we should know more soon.

[Guest]

I get your point on this runway, but there's too much going on here. There is an obvious issue with #1 from the beginning of the take-off roll. But that shouldn't prevent rotation at Vr. It should still fly. It looks more to me like they rejected at V1 or earlier but didn't retract thrust for some god-knows-why reason and simply applied brakes. It also looks suspiciously like two pilots flying the plane with very different intent, one intending to continue after the engine failure is detected and the other on the brakes. We've seen that before.

If there was a issue with #1 from the beginning of the take-off roll, there was time to reject and have enough runway. Probably, you are right one pilot wanted to continue and figure out once in the air what to do and the other one wanted to stop.

[3WE]

***Vr is a typical distance beyond V1***

Are we sure it’s a distance?

Slightly edited.

[Evan]

Are we sure it’s a distance?

"is" as in "occurs", which is clearly expressed in the context: "If you are on a legal runway length, and Vr occurs at a typical distance beyond V1..." Yes, we are talking about distance here.

[Gabriel]

I am sure he understood and was just being a [BLANK].

[Guest]

Are we sure it’s a distance?

But calculated as a speed... We look at a speed

[LH-B744]

I am sure he understood and was just being a [BLANK].

Ahm. I am hopefully allowed to be offtopic for one minute.

I lit 25 candles for you. Not as a revenge for what you did for me 8 or 9 weeks ago. But.. one candle for every year of your membership here at jetphotos? No, that wasn't it. But there was something.

Ah. Now I remember.

25 skyrockets for new years eve . Or simply, for you.

Happy birthday, my friend!

And now, back on topic.

[3WE]

But calculated as a speed... We look at a speed

So it’s not a distance?

And I may be a blank Gabriel, but shouldn’t you be blurting an acronym and giving a somewhat lengthy discussion about acceleration, speed and distance relationships and what constitutes reasonable assumptions?

[BoeingBobby]

Ahm. I am hopefully allowed to be offtopic for one minute.

And now, back on topic.

Now THAT is funny! You have NEVER been on topic once!

[Guest]

So it’s not a distance?

And I may be a blank Gabriel, but shouldn’t you be blurting an acronym and giving a somewhat lengthy discussion about acceleration, speed and distance relationships and what constitutes reasonable assumptions?

If you travel at a certain speed for a certain amount of time become a distance...

Basic physic, right?

We are pretty much all right...

But they told me to focus on a speed not to look for a distance before take-off when looking for a V1 and VR.

Or what shall I do ?

I am opened to suggestions

[3WE]

If you travel at a certain speed for a certain amount of time become a distance...

As long as you are certain

Basic physic, right?

With one caveat and a few moderately important assumptions.

We are pretty much all right...

Indeed, these types of crashes don’t happen that often.

[…]

Or what shall I do ?

I am opened to suggestions

Gabriel has one he’s mentioned before, with some moderately strong emphasis.

I did toy with the idea of an app for a smartphone or some sort of computerized, trend-tracking warning light.

[Gabriel]

shouldn’t you be blurting an acronym and giving a somewhat lengthy discussion about acceleration, speed and distance relationships and what constitutes reasonable assumptions?

Speed is the integral of acceleration over time.
Distance is the double integral of acceleration over time.
Take-off distance calculations, and the computing of the Vee speeds, assume a given acceleration, which is based on the thrust the engines are supposed to produce, the aerodynamic drag for the configuration that the plane is supposed to have, how much the plane is supposed to weight (mass), the assumption that the pilots will not be riding on the brakes (or have partial parking brakes applied), assumed runway slope, etc. A lot of supposed and assumed.

Planes (important ones) already measure acceleration so they could easily check, say at 60 knots, if the plane i accelerating as it was assumed during the take-off performance calculation. Hence TOPMS (Take Off Performance Monitoring System). Easy stuff.

Then you can mix that with aerodynamic data (the ground acceleration will not tell you that you are taking off with a 5 knots tailwind and not the 15 knots headwind you were supposed to have) and with GPS and runway map (nothing of the above will detect you taking off from the wrong intersection, or the wrong runway) to create the eTOPMS (e for enhanced).

Happy now, [BLANK]?

[3WE]

Happy now, [BLANK]?

Aggie Summary Statements (possible repetition of Gabellian aeroengineerspeak):

Because this involves acceleration, there can be compounding effects. (Is that important, Gabriel?)

So we assume that actual acceleration is close to what it should be.

We assume our safety buffers are adequate.

We assume the weather doesn’t throw big curve balls.

We assume that good data and calculations are used/made.

(And probably a couple more.)

By the way, 3BS is now in violation for multiple misuses of “we” and I anticipate appropriate physical, public punishment along with admonishment from Bobby, ATL and Kent.

I will be happy when said punishment is administered.