The maximum allowable zero fuel weight (ZFW) was 230,000 pounds. The crew-calculated weight and centre of gravity for the departure from Gander were within the prescribed limits.

The aircraft was owned by International Air Leases and leased to Arrow Air in October 1984.

Prior to departure from McChord AFB on 10 December 1985, the aircraft had undergone main- tenance at Oakland, California to rectify a number of deferred maintenance items (DMIs), including action to correct a reported rubbing associated with movement of the co-pilot's control yoke. The action taken was a check and cleaning of the area under the cockpit floor, following which it was noted that the yoke operated normally with no rubbing. The aircraft departed Oakland for McChord with the following four DMIs remaining.

Aircraft log sheets pertaining to flights after arrival in McChord AFB, on 10 December 1985, were not recovered. It was determined from the crew who flew the Cologne/Cairo flight sectors on 11/12 December that no further unserviceabilities had been entered prior to the aircraft's departure from Cologne on 11 December 1985. Servicing action in Cologne upon return from Cairo had included an oil top-up on each engine, the addition of seven quarts of hydraulic fluid to the hydraulic system, filling of the aircraft water system, and attempts to repair a leaking coffee maker.

No mention of any unserviceabilities was made by crew members to the servicing crew at Gander.The servicing crew did not observe any abnormalities with the aircraft.

The crew who flew the aircraft on the Cologne/Cairo flight sectors reported that there was a "ratchetting" when the co-pilot's control column was moved. This ratchetting was described as a clicking sound accompanied by a soft vibration and slight restriction in movement near the forward limit of the column travel. This information was passed verbally to the repair technician in Cologne, but no attempt was made to trouble-shoot the defect, nor was any entry made in the aircraft log.

The number four engine exhaust gas temperature (EGT) was reported to be indicating about 40 degrees hotter than the other three. The crew was adjusting the throttle during take-off and climb to keep the EGT under limiting values. Reportedly, this condition had existed for some time and was known to the crew of the accident flight. A review of the aircraft maintenance records determined that this temperature differential had been entered on previous occasions and was believed to be the result of a problem with the temperature indicating system.

The Board held a public inquiry into this accident in April 1986. At the inquiry, conflicting testimony was heard regarding the in-flight illumination of an engine thrust reverser unlocked light. The co-pilot and flight engineer of the Cologne/Cairo sectors reported that one of four such lights was occasionally illuminating in light turbulence during cruise. They could not identify the specific engine, but the first officer believed it was either the number three or the number four. The captain did not recall such illumination, nor could he recall any such observation by the other flight crew members.

Similarly, there was conflicting testimony regarding two missing side panels in the number three cargo pit. The flight engineer on the Cologne/Cairo sector testified that, while supervising the loading of the aircraft in Cairo, he observed that the panels were missing, and, as a result, fluid lines were exposed. He further testified that he informed the captain. The captain testified that he could not recall being so advised by the flight engineer.

In May 1981, the aircraft experienced an uncontained failure of the number one engine during take-off at Casablanca, Morocco. Considerable shrapnel-type damage was sustained by both wings, the landing gear, and the horizontal stabilizer. Major repairs, including the repair of punctures and dents to the ailerons, flaps, and horizontal stabilizer, were carried out by the aircraft operator, Union des Transports Aériens, after the accident, and the aircraft was resumed to service. As part of the repair process, engineering drawings were submitted to Douglas Aircraft Co. for their approval. The repairs, as planned by the operator, were approved by Douglas Aircraft Co., subject to certain conditions. Certain repairs were considered by Douglas to be temporary in nature and therefore life-limited. It was their recommendation that these repairs be replaced after a specific number of flight hours and, in the interim, be subject to inspection at regular intervals.

In November 1981, the aircraft was sold and imported back to the United States. At that time, Federal Aviation Administration (FAA) Form 337, Major Repair and Alteration, was completed by the vendor. The specific repairs accomplished were identified, and replacement and inspection cycles as recommended by Douglas Aircraft Co. were detailed.

No evidence was found to indicate that the specific inspections had been carried out. However, the repairs were in locations that would normally be inspected during routine inspection cycles.

In June 1984, repairs to the trailing edge honeycomb panels of the left and right wings, which were nearing the end of their life-limits as recommended by Douglas Aircraft Co., were inspected by an FAA designated engineering representative. As a result of this inspection, replacement of the honeycomb panels was extended to the next heavy check, subject to the inspection cycle recommended by Douglas Aircraft Co.

At the Board's public inquiry, Arrow Air's Director of Maintenance testified that he had been unaware of the Casablanca accident and subsequent repairs to the aircraft. He had no knowledge of the required inspection cycle or the life-limits on the repairs accomplished in 1981. Examination of the aircraft records determined that, although a heavy check had been accomplished after June 1984, replacement of the trailing edge repairs had not occurred. The life-limits on the other repairs had not been reached at the time of the accident.

In the days following the accident, numerous individuals came forward to relate their observations regarding the condition of the aircraft and to describe certain events that had occurred in the several months preceding the accident. Most of these observations related to the condition of the cabin and were considered by the Board to be primarily cosmetic in nature. Several of the observations did relate to the airworthiness of the aircraft and were determined to be either unserviceabilities that had been entered in the aircraft technical log and rectified or claims that could not be confirmed.

A review of aircraft servicing and maintenance records for the six-month period from June to December 1985 revealed that replenishment of aircraft hydraulic fluid was a recurring action. In the two days prior to the accident, 13 quarts (six quarts at McChord AFB and seven quarts at Cologne) of fluid were added to the system.

The aircraft potable water system had a history of leaks. The most recent maintenance on the system was performed at Oakland prior to the initiation of the 10 December flight from McChord AFB. In response to a maintenance entry that indicated that the system supply line was leaking in the number three cargo pit, the following rectification was entered: "Replaced line at seat 27 ABC. Replaced line in forward pit #1, lav line broken."

The water system was again leaking when the aircraft arrived at McChord on 10 December 1985. It was reported that potable water was not available to the rear lavatory. Problems with the system were mentioned by the captain in a telephone call from Gander to Arrow Air dispatch in Miami, just prior to the accident. The system was last filled prior to departure from Cologne on 12 December 1985.

Upon completion of the December 10/12 rotation flights, the aircraft was to be ferried to Oakland for replacement of the number four engine T-3 turbine disk which had 88 hours of service life remaining.