Thermostat
The AA crash in Chicago was blamed on the method used by AA to hang the engine. This was grossly misleading. The real problem was the fact that the loss of hydraulics (due to the loss of the departed engine) resulted in the LE slats (on that side) retracting. Why? because they were NOT locked down (as on the B727). The resultant roll caused the loss of the 'plane.
First, indeed, the primary cause was blamed on uncommanded slat retraction on the outboard left wing. But there were many other causes and issues identified in the NTSB report.
Why did the slats retract uncommanded? Because the engine and pylon both went over the top of the wing causing hydraulic and electrical damage and failures.
Why were the slats not lock down? Because this was not a requirement at the time.
Why did both the pylon and engine go over the top of the wing? Because the pylon/engine assembly was damaged during installation at American Airline's maintenance facility.
Why was it damaged? Because the forklift being used ran out of fuel and a resulting hydraulic check valve leak permitted the assembly to drop resulting in the initiation of a large stress induced crack in the rear of the pylon.
Why was a forklift being used to remove/install both engine and pylon instead of removing/installing separate units? Because it saved time and money.
Some more details in the NTSB report you failed to mention:
1. Based on a study performed by J.H. Wiggins Company at the time, the probability of an uncommanded slat retraction during takeoff was somewhere between one in one hundred million to two chances in a billion.
2. The forklift being used was written up as defective because it drifted down under load. The engine + pylon assembly weighed over 13,000 pounds. No corrective action was taken until 3 months had elapsed from the time it was used on the assembly in question.
3. The revised Damage/Tolerance concept was not in effect at the time the DC-10 was designed and what was being used at that time did not contain newer requirements on the certification of structural design (the pylon is a structure). Had the requirement for accidental damage evaluation been in effect when the DC-10 was designed, one might expect that such consideration would have been given to accidental damage to the upper flange of the pylon aft bulkhead.
4. The certification of the DC-10 was carried out in accordance with the rules in effect at the time. The premises applied to satisfy the rules were in accordance with then accepted engineering and aeronautical knowledge and standards. However, in retrospect. the regulations may have been inadequate in that they did not require the manufacturer to account for multiple malfunctions resulting from a single failure, even though that failure was considered to be extremely improbable.
5. The uncommanded slat retraction in itself did not cause the plane to crash. Had the dc power been active, the pilots would have received warning of this condition and would have determined the roll to the left was a response to an impending stall situation based on a stall warning devise that was also not operational. They could not see the wing, slats or the missing pylon/engine from the flight deck.
IMHO, using "selective data" from a 30 year old accident to offset an equally flawed (Rutan's opinion) does little to clarify the more recent accident. Hopefully, the BEA final report on AF447 will provide not only probable cause but positive change recommendations, based on their findings, to once again improve aviation safety, just as the NTSB report did 30 years ago…