The Board found no reason to conclude that the accident was the result of an aircraft unserviceability or malfunction. Nevertheless, during its investigation of the accident, the Board did observe certain maintenance-related practices and methods of operation that were not in accordance with approved and recommended procedures and which had the potential to adversely affect safety.

In the two December 1985 series of rotation flights between the United States and Cairo, there were at least four occasions when the Board believes maintenance entries should have been made in the technical log of the aircraft. These relate to the ratchetting of the co-pilot's control column, the illumination of the thrust reverser unlocked light in flight, the missing panel in the cargo hold, and the abnormally high number four engine exhaust temperature indication. In each case, the problem should have been entered in the technical log and the situation either rectified or, if possible, deferred within the guidelines of the company's DMI policy. In none of the four cases was this action taken.

The Board is particularly concerned with the decision of Arrow Air aircrews to accept an aircraft that exhibited anomalies in the operation of the flight control system. Further evidence of this attitude and the willingness on the part of flight crews to accept for flight aircraft with known unserviceabilities are the two separate flights operated by the captain, with an unserviceable main hydraulic system.

The Board considers that these actions were those of well-meaning flight crews who believed that the flights could be undertaken without jeopardizing the safety of passengers or crew. Among the factors likely considered by flight crew in making such decisions were the logistical problems that would arise by delaying a flight at an en route station and the probable domino effect on company operations caused by a significant delay in one of its flights.

Nonetheless, the Board considers that this practice represents non-compliance with established airworthiness standards and an unnecessary reduction in flight operations safety margins.

Problems were being experienced with the aircraft potable water system. Despite repeated repair action, maintenance personnel were unable to rectify the problems and keep the system in a serviceable state. Although repairs to the system had been carried out in Oakland prior to the rota- tion flights which commenced on 10 December 1985, it is evident that leaks were present during the night to and from Cairo. Despite the leaks and the knowledge that water was leaking into the aircraft, Arrow Air personnel continued to have the system replenished.

Similarly, the frequency of the replenishment of hydraulic fluid indicates that the aircraft's hydraulic system was leaking fluid at an abnormally high rate. Although this problem had been occurring for at least six months prior to the accident, it was not apparent that Arrow maintenance personnel had taken definite action to identify the source of the leakage and rectify the problem.

In addition, Arrow Air maintenance personnel did not identify the requirements for inspection and replacement of some of the repairs made to the aircraft following the 1981 accident in Casablanca. The life-limit on one of the repairs had expired without action being taken to replace the repair.