November 5, 2001
Captain Ray Lahr (ret)
18254 Coastline Drive
Malibu, CA 90265
Ronald S. Battocchi, General Council
National Transportation Safety Board
490 L’Enfant Plaza East, S.W.
Thank you for your letter of October 31, 2001. However, it still doesn’t address the issue. Let me explain the issue again. The NTSB made some secret calculations which led to an absurd zoom-climb conclusion. Then when challenged, the NTSB hid behind the claim that it used secret data which was “proprietary”. I submit that this is contrary to the basic mandate of a public accident investigation. Data and calculations which are fundamental to the conclusions reached in an accident investigation should be verifiable by all parties to the investigation and should be public knowledge.
Any kid who has played on a teeter-totter understands the fundamental principles involved in this issue. An aircraft in flight is analogous to a balanced teeter-totter. Suppose we have 574,000 lbs (the weight of TWA 800) on one side of a teeter-totter. That is a lot of weight so it is placed close to the center support (the center-of-gravity of TWA 800 was at 21.1% MAC which was about one foot ahead of the center-of-lift of the wing at 25% MAC). In order to balance the teeter-totter, we place a light load at the other far end (in this case, the tail of TWA 800 was exerting a downward force of about 5,218 lbs at a point about 110 feet behind the wing’s center-of-lift). TWA 800 was in balance which is a requisite for stable flight (574,000 lbs x 1 ft = 5,218 lbs x 110 ft).
Now look what happened when the nose of TWA 800 was blown off. The nose weighed 79,394 lbs. The center-of-gravity of the remaining 494,606 lbs moved aft to 11 ft (57.8% MAC) behind the center-of-lift. Now both the weight of the aircraft and the downward force of the tail combined to produce a nose-up torque of about 6,000,000 ft lbs (494,606 lbs x 11 ft + 5,218 lbs x 110 ft). It is like the heavy rider on a teeter-totter jumping to the other side – both riders slam to the ground.
How fast did the teeter-totter slam down? Boeing said that after nose separation, the angular moment-of-inertia was 15,780,000 slug ft^2. Dividing that into the torque gives an angular acceleration of about 22 degrees per sec^2. In one and a half seconds, the aircraft had pitched through full stall and was in free fall. Assuming the wing held together, the most the aircraft could have climbed before stall was less than 200 feet. This data was provided by Boeing. You can see that the 3,000 ft zoom-climb proposed by the NTSB was quite impossible. Somehow, the NTSB made a mistake in its calculations.
I believe my FOIA citizen rights entitle me to access the records, and I repeat my appeal for the records of the NTSB regarding its hypothetical zoom-climb.
Open Letter Sincerely,