Arrow Air's insurer, Associated Aviation Underwriters, dispatched a private insurance investigator named Irving Pinkel to the crash site in Gander in May, 1986. Pinkel was looking for evidence which might demonstrate an explosion or fire on board the aircraft before impact. At this point, the CASB had turned the wreckage back over to Arrow Air.

He discovered two pieces of the fuselage measuring about 30 square feet each with pronounced "outward pucker" suggesting that these panels had been "punched out" by a strong force from the inside out at high speed. One of the fuselage sections had no sign of impact damage on the interior panel making it unlikely that impact could have caused the separation. It more logically suggested a pre-impact force. (see Exhibit 39)

In a letter dated November 6, 1986 from Peter Boag, the CASB's chief investigator to AAU's counsel John Martin all of these findings are refuted. Boag says the RCMP's forensics people found no evidence of explosive residue and that the CASB's engineering section concurred. (see Exhibit 40) Here are Boag's conclusions: "it was concluded that the damage occurred during break-up of the aircraft and subsequent post-impact fire".

According to a source close to the investigation it is impossible for explosive residue to survive a 20 hour fire. These sections had been badly burned and there was no possible way to categorically rule out any form of explosion. The least Boag could have said was that it was not possible to determine whether or not there was an explosion due to intense combustion of materials. Peter Boag's interpretation clearly demonstrates a bias.

Another section of Pinkel's report points to the possibility of damage to the No. 3 engine being caused by explosion fragments. Pinkel says; "However, three consecutive vanes of the number 3 engine show a slight flattening of the leading edge of the inlet guide vanes. Examination of these vanes at moderate magnification showed that the middle one had a faint marking off red orange color on the leading edge that extended for a 1/4" around the edge". (see Exhibit 39)

Pinkel's report says that ingestion of explosion fragments by engine No. 3 would cause compressor stall which would explain the plane veering to the right before impact. He added, "compressor stall is usually accompanied by flames torching from either the engine inlet or tailpipe or both". This would explain what eyewitnesses claim was an "orange glow" coming from the underside of the aircraft. However, Pinkel's findings were never substanciated by the CASB.