737-400 testflight with wing stalls before autoslat.

737-400 testflight with wing stalls before the autoslat systems operates. These flight where performed due to the fact that the wingtip (first LH and then RH) stalled before the autoslat system comes into action. After several flights and adjustments it appeared that the slat auxiliary track detent arms where out of adjustment, causing the wing to stall before the slats move from extend to full extend. The fact that the stall test was performed initially, is because this a/c had undergone a heavy D check, and company policy , together with AMM requirements, requires a testflight after such a large check. The testflights where performed in 2003.

Category:

Science & Technology

Tags:

• 737-400
• stall
• aux
• tracks
• autoslat
• wing
• sjap

[737maint]

The stick shaker operated on the last testflight later in this video. Before it didn't because when the stall occured, the pilot recovered the a/c and did not lower the airspeed further more. Icing conditions do not do anything with it, the shaker only operates when autoslat already tried to save the plane, and the airspeed decreases further and higher angle of attacks are encountered.

[blampa]

Loved how the areas beyond the slats near the wing tip showed the turbulence of the transient separation, great visual representation of what happens in a stall and the aerodynamic affects of slats.

[kneejouster]

@BermudaGreenNox

clicked thumbs down by accident and it's not letting me undo it :(

[flchange]

that guy talking all the time is annoying...

[BermudaGreenNox]

Is this plane from KLM?

[rmlchin]

fantastic video.

[JetMechMA]

@737maint

The only thing here I would call abnormal is one wing falling off before the other. The stall should be gentle, level and predictable. I've corrected rig problems before and they were always the trailing edge flaps...usually the aft flap segment eccentrics needed adjusting. The leading edge slats are a little more mechanical than the trailing edge with all their monkey-motion.

[JetMechMA]

How did the aux track detent arms cause the wing to stall before auto-slat? I would think it was something more to do with the trailing edge flaps. Isn't stall warning and therefore auto-slat) a function of angle of attack? Therefore auto-slat isn't going to activate until a stall is reported to the flight warning computer. So, to me, auto-slat after stall is normal ops.

[JetMechMA]

@737maint

Stick shaker is strictly tied to the AOA. In fact you can put the aircraft in the air mode and reach out with a coat hangar and move the AOA vane into the extreme position and the stick shaker will activate.

[KartKing4ever]

i wana c a plane just fall, like a real stall

[megathumper777]

Fantastic. Thank you for sharing this with us.