Page:NTSB Report, 1967 Lear Jet crash.pdf/15

- 12 - system is designed to have only one inverter at a tune supply power. Either inverter supplies AC power to the 26 volt AC circuit and the respective primary or secondary bus; however, power to the other bus is available only through a bus tie breaker.

From the evidence and the Board's expertise it is concluded that the aircraft would be difficult to control during night operations, in turbulence, with the gyro horizon and yaw damper inoperative. The Flight Manual states that the yaw damper must be operative for all flight conditions except takeoff.

2. ANALYSIS AND CONCLUSIONS

2.1 Analysis

The crew was properly certificated and the aircraft gross weight and c.g. were Within allowable limits. The aircraft was not ready for flight with passengers and was in a test status at the time of departure from Wichita.

The unique circumstances and certain management decisions pertaining to the modifications to N804LJ resulted in the aircraft being worked on by both the production and the service departments of the company. A company official signed for work which was not inspected, and deleted the requirement for other work items because they were to be accomplished by the production department. The production department, normally working with an O & IR, did not assume responsibility for the inspection of any of their work except that which was integral to the buildup of the units or wiring installed. Additionally, no O & IR was even issued in connection with the work done. Thus the aircraft arrived at the flight department without the