Page:CAB Accident Report, American Airlines Flight 383.pdf/24

– 23 – procedures, the completion of this turn to final would have required the aircraft to be in a landing configuration, with airspeed and rate of descent stabilized at or near appropriate values. However, it can be seen that even in the later phases of the turn the airspeed was still above 40-degree (landing) flap extension speed, the landing gear had not been extended, and the landing checklist obviously was not completed. Because of the number of essential landing items still incomplete this late in the approach there can be little doubt that the cockpit crew would have been extremely busy at this time and more than likely throughout most of the base leg.

Consideration must be given to the fact that these two qualified B-727 captains had flown together on seven previous flights, knew each other well, and most probably had established a high degree of reliance on one another's operational capabilities.

It is possible that the check captain, confident in the other pilot's ability to operate the aircraft safely, would assume that the altimeters and other flight instruments were being monitored and could therefore concentrate on maintaining visual contact with the airport. Moreover, it is possible that the captain being observed was secure in the knowledge that a well qualified check captain was in the right seat performing copilot duties. He could therefore in view of the rapidly decreasing visibility, concentrate on keeping the airport in sight, depending upon visual reference to ground lights for altitude guidance, with the assurance that the check captain was monitoring the flight instruments and would alert him to any unusual contingency.

American Airlines operational procedures require that the pilot not making the landing call out the airspeed, altitude, and rate of descent at 500 feet a.f.l., and also the rate of descent any time it exceeds 700 feet per minute below an altitude of 500 feet a.f.l. The flight recorder readout shows that at 1900:45, about 42 seconds before ground impact, the aircraft was descending through 500 feet a.f.l. near the midpoint of the base leg and that the rates of descent remained in excess of 700 feet per minute throughout the remainder of the approach. It is evident that either the AA altimeter monitoring procedures were not being followed or that a misreading/misinterpretation of the altimeter occurred which indicated higher values to the check captain (pilot not making the landing). It should be noted that if the check captain was concentrating on maintaining visual contact with the airport the limits of his line of vision would have been between 80 and 45 degrees left of dead ahead. It can be seen that with his heavy workload; extending flaps, performing the landing checklist, making all radio transmissions, and trying to keep the field in sight, he would have had little time to swing his gaze back to his own instrument for altitude reference. Aside from, but compounded with any other altimeter misread/misinterpret possibility, the probability of error is enhanced when reading the instrument from a side angle which in this case would have been approximately 55 degrees left of forward. It is doubtful that the center (No. 3) altimeter would have been used on the approach as it would not have been indication absolute altitude over the airport as were the Nos. 1 and 2 altimeters.

It is reasonable to assume that the flight engineer would have been engaged in duties attendant to completing the landing checklist and would not have had time to devote his full attention to the monitoring of flight instruments during the descent along the base leg.