View Single Post
Old 29th Aug 2008, 01:36
  #1191 (permalink)  
lomapaseo
 
Join Date: Mar 2002
Location: Florida
Posts: 5,148
I just ended a fast reading of the NW255 report, and I have some conclusions.

They lifted off the aircraft because were taking off from a 8500´ runway, and there wasnt much distance remaining. They forced the pitch up to get airborne.

If there was not a light pole, probably they didnt crash, because the plane was gaining altitude and decreasing their AOA very slowly. The report states that they only needed 11 degress of pitch up to stop the stick shaker.

Lateral inestability also appeared, they needed to overcome a dificult roll and gain control, and almost they did it.

In Barajas, there was plenty of take off distance available. Also probably ground effect. If we are talking about a no Slat/Flaps scenario, the chances of a succesfull take off in this kind of runway with this weather are high. Only the crew could worsened their odds keeping a high pitch angle, while ignoring the loss of speed and the warnings.

The NTSB estimated that an MD82 with the NW255 weight needed 11300 feet from the brake release point to reach 41 feet. In the runway 36L of Barajas you have 14272´of distance available.
From what I have seen with numerous DC9 series takeoff stalls (many due to ice on no-slat aircraft) the biggest problem was the loss of lateral control and/or roll just out of ground effect. True the aircraft may climb but not all the wings wish to follow and once you catch a wing tip it's all over.

I seem to recall that some aircraft e.g. Delta B727 and LH B747 dragged their aft fueslage over rough ground and that ended the flight.
lomapaseo is online now