Aviation Accident Report: Pan American Airways Flight 517-518

Aviation Accident Report: Pan American Flight 517-518
by the Civil Aeronautics Board

File No. 5105-41

of the
Investigation of an Accident Involving Aircraft
in Scheduled Air Carrier Operation

An accident which resulted in extensive damage to a Boeing model 314 flying boat, NC 18601, owned and operated by Pan American Airways, Inc., occurred at Apra Harbor, Guam, about 11:00 p.m. G.C.T. on August 16, 1941. No injuries were sustained by any of the 29 revenue passengers, the 16 non-revenue passengers, or the crew of 10. The crew included Captain Henry J. Chase, Copilot Edwin Davis Avary, and Third Officer R. N. Brown, each of whom was properly certificated and appropriately rated. The other members of the crew were R. C. Campbell, Second Officer, R. N. Goodson, First Engineer, J. B. Parrish, Second Engineer, P. Williams, First Radio Officer, R. B. Hanley, Second Radio Officer, and William Murray and A. Chanco, Flight Stewards.

The flight, designated by Pan American Airways, Inc., as Trip 517-518, had originated at San Francisco and was returning to that point from Singapore. A landing had been made at Guam, which was one of several intermediate stops. Because of unfavorable take-off conditions, consisting of heavy swells in the outer harbor, light wind (6 to 8 knots) and heavy load (28 pounds less than the maximum permitted), the attempted take-off from Guam was delayed about 2½ hours. When the take-off was attempted, a runway in the inner harbor, protected from heavy swells, was used. This runway has a clear channel about 6000 feet long. Uncertain that he could accomplish the take-off in this distance, Captain Chase decided that unless he should become airborne before reaching it, he would discontinue the attempt at a pre-selected point where he still would have adequate space to come to a safe stop. The spot he chose for discontinuing the take-off was judged by a buoy, the location of which was misinterpreted because, unknown to Captain Chase, a similar buoy was absent from its proper place. This confusion in the channel markings led the copilot to prolong his take-off attempt 200 years beyond the intended point, and, in bringing his craft to a stop, the captain failed to clear a coral shoal which damaged the bottom of the hull.

PROBABLE CAUSE: Absence of a marker buoy from its proper place on the marked runway.



This work is in the public domain in the United States because it is a work of the United States federal government (see 17 U.S.C. 105).