Crash 737 Islamabad

[Dmitry]

But with that much altitude to recover, is windshear really a danger in itself?

I think so. However it's not all about the altitude. There're many pics on the web.

http://www.stereovisionengineering.net/microburst_scenario.jpg

[Dmitry]

While we're discussing the weather, Pakistan's civil aviation authority report that aircraft's tanks had exploded before it hit the ground.
The version of lightning strike is as possible as the technical failure.

http://www.telegraph.co.uk/news/worldnews/asia/pakistan/9218155/Pakistan-plane-crash-Fuel-tanks-exploded-mid-air.html

[Evan]

While we're discussing the weather, Pakistan's civil aviation authority report that aircraft's tanks had exploded before it hit the ground.
The version of lightning strike is as possible as the technical failure.

http://www.telegraph.co.uk/news/worl...d-mid-air.html

While aircraft are fairly immune from conventional lightning, there is an extremely rare form of positively-charged lightning that is far more powerful and can cause such a scenario. It is suspected in the Pan Am Flight 214 B707 incident where that aircraft was apparently destroyed by a lightning strike.

http://en.wikipedia.org/wiki/Pan_Am_Flight_214

[AVION1]

sounds like wind shear to me.
who is in charge of this investigation?...do they send their FDR and CVR to France or to the USA?

[Dmitry]

sounds like wind shear to me.
who is in charge of this investigation?...do they send their FDR and CVR to France or to the USA?

It's written that the FDR and CVR will be sent to the foreign specialists. It's prohibited for Farooq Bhoja (the owner of the company) to leave Pakistan.

[MCM]

Evan,

It is unlikely that plain windshear at 4000ft would, in itself, be a major problem. However, microbursts are another thing entirely, and could cause an issue.

Microbursts are able to, quite comfortably, push jet aircraft into the ground. And are the reason you don't make approaches when thunderstorms are nearby unless you are damn sure there is nothing around (there are some microburst warning systems at certain airports which give a good idea).

I remember trying a windshear recovery in a 747 simulator. The microburst event was based on an actual event (which the aircraft successfully flew away from). At 1500ft the predictive windshear went off "Windshear Ahead". Even knowing it was coming, and having prepared the response, I flew out the back of the microburst at 8ft. Thats right, 8.

Another event I am aware of resulted in a 737 using full go around thrust, and only just being able to maintain level flight.

That isn't saying that is what happened here - there are any number of causes. Fuel tank explosion as speculated - it could be. Lightning? Possibly. Fuel vapour? Possibly.

[Evan]

I remember trying a windshear recovery in a 747 simulator. The microburst event was based on an actual event (which the aircraft successfully flew away from). At 1500ft the predictive windshear went off "Windshear Ahead". Even knowing it was coming, and having prepared the response, I flew out the back of the microburst at 8ft. Thats right, 8.

8ft RA? I guess the gear was retracted. What was your altitude when you flew into it? Can microbursts really push an aircraft down from something like 4000ft?

[Evan]

And are the reason you don't make approaches when thunderstorms are nearby unless you are damn sure there is nothing around (there are some microburst warning systems at certain airports which give a good idea).

It is reported that an Airblue flight landed five minutes after the crash (an A319 or A320). If there was microburst activity, would that flight have received a predictive windshear alert, or is microburst so transient that a matter of minutes would make all the difference?

[MCM]

A matter of minutes most definitely can make the difference. They usually only last 5 or 10 minutes anyway.

The training exercise was flown into at about 1300ft from memory.

Yes, microbursts are that strong. Of course, ones that strong are very rare.

The definition notes that they can reach windspeeds over 270kph, with the downdrafts being the dangerous bit.

There were a number of big accidents from them before we started to understand them a bit better. Delta lost a L1011 from a microburst.

Microbursts are the real reason you don't make approaches near thunderstorms, not the lightning or the rain.

[Evan]

I take it Bhutto does not have TDWR. Is on-board dopplar a common retrofit on older passenger jets? With windshear being an everpresent threat, it seems as important to safety as TCAS or GPWS.

[mawheatley]

There were a number of big accidents from them before we started to understand them a bit better. Delta lost a L1011 from a microburst.

Microbursts are the real reason you don't make approaches near thunderstorms, not the lightning or the rain.

They also continue to do damage on the ground. My wife is a Flight Attendant (coincidentally for DL) and she tells of this time she was crew on a 727 or MD88 into somewhere in Florida. They landed safely, got to the terminal and everyone got off. They were leaving the aircraft when they saw a microburst coming. She describes it as being like a black wall of cloud coming across the airfield. When it got to the aircraft she'd just got off it picked up the tail section and slammed it down, making the front of it damage the jetway.

[3WE]

I remember trying a windshear recovery in a 747 simulator. The microburst event was based on an actual event (which the aircraft successfully flew away from). At 1500ft the predictive windshear went off "Windshear Ahead". Even knowing it was coming, and having prepared the response, I flew out the back of the microburst at 8ft. Thats right, 8.

More MSFS apologies. Again not 100% accurate, but still in the ball park.

It's very easy to program in Delta 191 35 knot headwind first dies, then becomes a 35 knot tail wind, It starts at 800 and hits hard around 400ft. Be sure that the there's also a changing crosswind component to make the plane yaw, and do it in at least 2 increments- to not be overly unreal.

Choose a big plane (Usually used a DC-10, as L-1011 were not as available).

Yeah, you know it's coming.

The really really really scary thing was the first time I tried it...I gently touched down just about where Delta 191 touched down, before it crossed the highway.

The other really scary thing was that about the only time I would succesfully recover were when 1) I hit full power the instant that the speed first dropped, or 2) was gross sloppy hot coming into the wind shear.

On the realism front, MSFS lacks cars and water-tanks that 191 dealt with

Yeah, theoretically they should have been able to fly out. But that's awfully easy to say from the arm chair.

[Gabriel]

The pilot (FO) performance (in the "fly the plane" part, I mean) was a significant factor too, due to his wrong reaction to... yes, a stall warning.

In this case, though, instead of not lowering the nose as per my usual rant, the pilot over reacted to a transient 1 second stickshaker by pushing down A LOT (I don't remember how many pounds of push force he used) effecivelly puting the plane in NEGATOVE Gs, lowering the nose a lot of degrees, and building a too high sink rate (additionally to what the microbrust was already doing).

Not only that, but he did that twice, the last time when they were too close to the ground.

Yet, he managed to level-off skimming the ground and had more than enough performance reserve to pull-up more and climb, thus avoiding the initial touch-down.

I am not blaiming the pilot. He had not been trained to deal with these things. A modern pilot properly applying the escape maneuvers tought today would not have crashed that plane.

[MCM]

How about intermittent stickshaker for GPWS?

These are why some pilots get a little riled up when people make definitive statements about how to handle stall warnings. There are circumstances that it is appropriate to fly that close to the stall.

[Evan]

How about intermittent stickshaker for GPWS?

These are why some pilots get a little riled up when people make definitive statements about how to handle stall warnings. There are circumstances that it is appropriate to fly that close to the stall.

This is why I objected to all the praise given when stall procedures were revised to instruct pilots to first lower the nose to silence the stall warning. Yes, this must be done, but stickshaker AoA is not stall AoA and, if the ground is rising up to smite thee, lowering gently to silence and then raising gently to activate (and so on) until thrust can get you out seems like the thing that would save you. Thus, I think the procedure must be to manage AoA and pilots must be well-trained to understand what that means and how best to do it in a variety of situations. I think the procedure should just read: "Manage AoA. Smoothly add thrust". If the pilot needs more instruction then that, send them back to school.

Or should I post this in the "black and white thinking" thread?