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As previously stated, the failure of the safety lock bolts and the unscrewing of the brake cage resulted from improper tightening of the cage during installation. The recommended procedures for installing the cage specify that a cage wrench be utilized for this function. However, testimony of maintenance personnel indicates Standard Airways' Maintenance Base did not possess a cage wrench, but used a strap wrench for this purpose. Because of the tapered surface of the cage, it is considered highly unlikely that proper tightening of the cage would be obtained through the use of a strap wrench. This may well account for two different cage assemblies wearing through the safety bolts and becoming unscrewed at nearly the same time. These were the No. 3 cage (Power Unit 165047) on N 189S which failed on May 28, 1963, and the No. 2 cage (Power Unit 168011) on N 9742Z which failed on June 3, 1963.
The carrier's maintenance manual states that the Chief Inspector is responsible for compliance with all CAR's as regards maintenance, and that he shall be responsible for the acceptance or rejection of all work performed on company equipment by maintenance contractors. Additionally, the last designated Chief Inspector prior to the accident testified that it was his responsibility to, ". . .observe techniques, proper tools, proper equipment, proper parts," and when the Job was completed to, ". . . go out and go over the Job and see that it was properly done." Yet, the records indicate that the position of Chief Inspector was unoccupied from March 3, 1963, until after the accident occurred. Testimony by officials of the carrier was to the effect that acquisition of the Long Beach Maintenance Facility resulted in unnecessary duplications in the maintenance organization and that verbal instructions had been given as to who was the Chief Inspector during this period. This is pointed out only to illustrate that: Improper tools and procedures and inadequate inspection procedures were employed in the maintenance of two propeller power units that failed in flight, and that; within the framework of the carrier's maintenance system it is the Chief Inspector who is responsible for the detection of improper equipment and procedures, and that; although there was a designated Chief Inspector at the time the involved power unit brakes were adjusted, the records indicate this position was not filled for a period of time in which aircraft maintenance was continually performed. Although it may or may not have been understood by maintenance personnel who the Chief Inspector was during this period, the lack of a well organized maintenance structure is apparent.
It is evident that as early as February 18, 1963, both Standard and the FAA were aware of discrepancies in Standard's maintenance organization and in the maintenance records of Standard's L-1049 aircraft. In this regard a meeting was held on April 19, 1963, by FAA with company maintenance representatives in which the record status and maintenance organization were discussed in detail. In fact, a project completion date of May 27, 1963, was fixed wherein these discrepancies were to be corrected.
In summation, a review of all evidence indicates that the carrier's maintenance organization did not provide adequate maintenance records for N 189S, nor did it insure the performance of proper maintenance practices or inspection procedures necessary for adequate standards of airworthiness. These practices resulted in the failure of a propeller power unit directly linked to the cause of this accident.
