Doug got a question about the MD90

[Tim]

Last night there was an MD90 in ATL and we were looking at the engine mount and noticed what looks like a aileron or flap or trim tab on the very end. So I decided I would ask the expert what that is and what it is for

 

[derg]

That's a... shoot, dangit, what's that thing called.

Oh! Pylon flaps!

If the airplane is in a deep stall and you push the control column full forward to reduce the angle attack, those pylon flaps will deflect downwards to give you a bit more pitch authority to bring the nose below the critical angle of attack.

Swept-wing jets act crazy when you stall them and sometimes at high angle of attacks, the airflow from the wings can 'blank out' the stabilizer and prevent you from getting enough energy over the stabilizer surface to reduce the pitch of the aircraft.

 

[Tim]

Thanks I knew you would know. Are you going to be coming back through ATL later tonight.. I get there around 9.

 

[derg]

Actually at 2105 I'm working 2141 ATL-MLB.

 

[gay_pilot18]

So what are those retractable underwing wingtip lights for on the MD-88/90?


Corrie

 

[Tim]

If I get there in enough time I will try to swing by and say hi

 

[derg]

[ QUOTE ]
So what are those retractable underwing wingtip lights for on the MD-88/90?

[/ QUOTE ]

Landing lights.

 

[gay_pilot18]

[ QUOTE ]
[ QUOTE ]
So what are those retractable underwing wingtip lights for on the MD-88/90?

[/ QUOTE ]

Landing lights.

[/ QUOTE ]


Figured that but you don't see too many other airliners with landing lights on the wingtips. Other then MD-88/90's.

Though 737's have them on the flap fairings on the classic and the underbody on the NG's.


Corrie

 

[N519AT]

What about that rectangular thing behind the nose-wheel

 

[Joe]

It deflects any small rocks or debris from being kicked up by the gear into the engines.