Page:CAB Accident Report, Flying Tiger Line Flight 282.pdf/10

 and air traffic was duplicated while an aircraft flew the same flightpath as the accident aircraft. Portable TVOR receivers were also placed at several permanent locations to monitor the 287-degree radial signal. These tests revealed no appreciable effect on radial reception.

A review of previous L-1049 aircraft accidents indicates that a number of these were aircraft of the L-1049H series purchased by the Flying Tiger Line, and involved navigation errors of some type.

Subsequent to the accident a radio transfer switch assembly containing loose wire-clipping contamination was removed from a sister aircraft N6971C, as a result of extensive toubleshooting for a VOR course deviation bar discrepancy. Examination of this switch and another one removed from N6919C revealed short pieces of wire, varying from 1/16 to 1/4 inch in length within the wafer switch mechanisms. Several wire-to-switch terminals had untrimmed wire strands extending up to 1/2 inch beyond the terminal lug. A review of the last available log sheet of N6915C, the accident aircraft, revealed that the VOR system had writeups similar to N6917C. The log of N6915C indicated that the corrective action was removal of the VOR receiver which checked out normally during the subsequent bench check.

During the FTL campaign to examine all relay switches in the fleet, two switches were found to be contaminated and four were found to have a source of contamination present. Electrical shorts caused by relay switch contamination have been known to cause navigation bearing angle errors of as great as 60 degrees.

Subsequently, the Board in a recommendation to the FAA, suggested that all operators of this type aircraft examine the switch to determine if contamination existed. On May 20, 1965, the FAA issued an Airworthiness Directive applicable to all L-1049C, E, G and H series aircraft equipped with Lockheed Radio Transfer Switch Assembly, P/N319122, which required the disassembly and checking for wire clippings of each radio transfer switch assembly within the next 300 hours time in service. (See Attachment #5.)

2. ANALYSIS AND CONCLUSIONS

2.1 Analysis

An examination of the evidence indicates that the structure, powerplants, and system components were capable of normal operation prior to initial impact.

The medical records of all flight crewmembers failed to disclose any significant pre-existing diseases which would have disqualified any of the crewmembers from performing their duties for this flight.