Page:CAB Accident Report, Northeast Airlines Flight 801.pdf/6

 Examination of the recovered wreckage failed to reveal any indication of a structural failure or defect of the aircraft proper. Examination of the engines likewise failed to reveal any suggestion that they had not been operating properly at the time of impact. The landing gear was extended and locked at the time of impact and the wing flaps were extended to the approach position of 21½ degrees. The empennage was practically intact and all empennage controls were fully operable. All trim tabs were likewise found intact and operable. All three of these trim tabs were deflected, as shown by their indicators, amounts well within what would be expected for a normal approach.

Although the underside of the fuselage was generally collapsed, the forward portion of this fuselage underside was not comparably damaged, indicating that contact with the water was made in a tail low attitude. The cabin floor buckled upward under hydraulic loads.

Both altimeters were found set at 30.00, the setting last given the flight. One altimeter had been damaged to such an extent that it could not be functionally tested; the other was tested and proved to be within normal tolerances.

The matter of possible altimeter error was thoroughly explored as a result of this accident. It was developed that there are eight possible ways in which an altimeter can be in error. It is also shown that even if, by the most remote possibility, all eight of those errors had happened simultaneously, and further, if they had been additive, also a highly remote possibility, the total amount of the altimeter's erroneous indication would be but in the order of 110 feet.

Both air speed indicators were found to be within allowable tolerances when functionally tested. Both the captain and the copilot