Page:CAB Accident Report, Eastern Air Lines Flight 21.pdf/20

 mechanical failure, nor the presence of carburetor ice was a contributing factor in the crash. The fact that he was operating at a dangerously low altitude due to any of the foregoing reasons would have been apparent to Captain Perry if his altimeters were reflecting the correct altitude at the time, and he would have taken some emergency measures as outlined above to have averted the crash. Accordingly, we must conclude that Captain Perry did not know that he was flying at such a low altitude.

In order to have flown at such an unusually low altitude without knowing it, Captain Perry must have either ignored his altimeters altogether or must have placed reliance upon an altimeter, or altimeters, which were out of order or misset. It is inconceivable that he could have ignored his altimeters for in the performance of an instrument approach he must have placed complete reliance upon his instruments. Accordingly, we are left with only two alternatives, either that the altimeter, or altimeters, by which operations were being conducted were out of order, or that one, or both, were misset.

Although subsequent examination of the altimeters revealed no defect therein which had existed prior to the crash, that possibility cannot be excluded because of their damaged condition when found. In considering the possibility of malfunctioning of the altimeters, it is necessary to predicate the discussion on two hypotheses: (1) That both altimeters were out of order; (2) That one altimeter was out of order. On the aircraft involved in the accident both altimeters were connected to the sane static pressure line; therefore, any defect in this line would have resulted in the some error being registered by both altimeters.