A Possible Cause of the Continental 737 Crash in Denver

Posted on 03. Jan, 2009 by in Featured

The more I think about your theory, the more I think you’re onto something with the wing tips or winglets. The thing that keeps coming back to my mind is the loud noises picked up on the voice recorder and “bumpy” ride descriptions by flight crew and passengers….all leading up to the abort decision. That bothers me a lot. That’s why I think some failure with the nose gear was a significant contributor in the chain of events. Do you have any thoughts about what might have caused the noises and the rough takeoff roll?

More excellent questions from Rick; I hesitate to comment on an open investigation because all the details are not known. But Rick asked some excellent questions, rather than dodge them I offer this as a possible explanation and cause.

I will start out with the caveat this is speculation: In answer to Ricks question about the jolting ride and noise; both in my opinion were caused by the 737 skipping. I flew recently with a Captain (Len R.) who put forth this thesis. The 30 knot cross wind component was near the aircrafts limit and if the up wind wing rose due to ineffective control input it would cause the aircraft to become partially airborne. The main tires would not have enough down force to maintain friction with the runway. The result would be lateral skipping. The aircraft would hop laterally accounting for the jolting ride reported by the passengers. I looked a little closer, below is my assessment of this theory.

The 737 has an unusual landing gear set up. The nose gear is not on fuselage centerline because of this the main gear caster slightly, in my opinion once the 737 started to skip the castering gear would bang stop to stop making a loud noise.

Once light on the main gear the 737 would weather-vain into the wind. When the abort was initiated IMO the aircraft was weather-vained into the prevailing 30 knot wind. As the spoilers deployed the aircraft would squat back onto the main landing gear tires, re-establishing contact and friction in a yaw. Resulting in loss of control and the subsequent departure of the 737 from the runway.

The question is what caused the skipping. The crew was trained and experienced, IMO they would have had the proper control inputs applied. IMO a close look at the winglets/wing tips in a strong cross wind needs to be done. With special attention to the possibility of the winglet masking the aileron on the wing. If the aileron was even partially masked by the wing tip the input would not have been effective enough to hold down the wing and keep the main gear tires in contact with the runway maintaining sufficient friction for directional control. Again just an opinion.

3 Responses to “A Possible Cause of the Continental 737 Crash in Denver”

  1. Rick 3 January 2009 at 17:07 #

    Your and Len R’s theory is very sophisticated and well thought out. It’s quite credible because we “know” about the gusting at 33 knots with the 30 knot crosswind component. We don’t “know” anything right now about the nose gear. Of course we’ll all be watching closely in the next few days what is said about the nose gear. I am wondering if the flight data recorder will be able to pick up data that will illustrate the physical events in your theory. Thank you also for the quick response. As a pilot, I’m very curious about this entire event.

  2. Rick 11 January 2009 at 08:35 #

    OK so now we have a new development on Jan 7…the Captain says the plane had a sudden deviation to the left of centerline and off the runway with no rudder control. He couldn’t even correct the deviation using the tiller. Is this a continuation of the mysterious rudder problem(s) with the 737, or do we go back to a failure with the nose gear…either a flat tire or something else? I’m very interested in your opinion following this development.

  3. chip 15 January 2009 at 00:46 #

    I just got off of a 3 day trip no computer access. To answer your question it could be any of the causes you raised. Also you can add CG problems. If the CG was too far aft it would explain the sudden movement; ie the nose wheel loses contact w/runway. I think it may turn out to be a combination of things. Some more info should leak out soon, it always does!

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