Aviation Accident Report: Pan American Airways flight on 23 October 1940

by the Civil Aeronautics Board

CIVIL AERONAUTICS BOARD
WASHINGTON, D. C.

FOR RELEASE

REPORT OF THE CIVIL AERONAUTICS BOARD

of the

Investigation of an Accident Involving

Aircraft in Scheduled Air Carrier Operation

 

4206-40

 

Mrs. Virginia Gilesby, a passenger, was slightly injured in an accident which occurred off Darrels' Island, Bermuda, British West Indies, on October 23, 1940 about 6:51 p.m. EST. The aircraft, a Pan American Airways Sikorsky flying boat, Model S-42-B (NC 16735), was slightly damaged. In command of the flight was Captain W. B. Culbertson, who held a commercial pilot certificate with a Class 5 Water rating and who had accumulated about 12,000 hours flying time. First Officer L. C. Lindsey, who was properly certificated and appropriately rated, and five other members completed the crew. None of the crew or any of the other nine passengers was injured.

The aircraft departed Baltimore, Maryland at 12:31 p.m. EST on a regularly scheduled flight to Bermuda, with a crew of seven, ten passengars, mail, express and baggage. The aircraft was loaded within its placarded limits. The weather was excellent at the time of departure and throughout the trip. The flight proceeded without incident until about 4:35 p.m. when the Captain received a radio message to the effect that the power boat equipped with a search light, which is normally used to aid aircraft in night landings, was out of commission and that a small boat which was not equipped with a search light would be used instead. The Captain subsequently stated that, since it appeared that the fuel then on board was insufficient for a return to Baltimore, he decided to continue to Bermuda. Shortly afterwards, he received the routing message relative to landing conditions, showing the Kollsman setting as 30.02. The captain asked for confirmation, since a message previously received had given the setting as 30.22. The setting of 30.02 was confirmed. The flight arrived over Bermuda at approximately 6:25 p.m. EST. To assist the pilot in making night water landings there, eleven electric lights, placed about 300 feet apart, are arranged in a straight line in the landing area, heading into and parallel with the prevailing wind direction. The light on the approach end is green, the next nine, white, and the last one red. The landing is made to the right, parallel with the lights. The Captain circled the landing area during his descent, found the line of lights properly placed into the wind, and received a green flare from the launch, indicating that the area was clear of obstructions. At an altitude of approximately 500 feet, he lined the aircraft up with the lights for a final approach and started a descent at a rate of 300 feet per minute and 90 knots indicated air speed, with full flaps. When still well back of the first light and while it was evident that the plane was well above the surface of the water, the Captain noted that the Kollsman registered about 10 feet. He slowed the rate of descent to about 100 feet per minute and his air speed to 75 knots, and ordered the landing lights turned on. He then asked the First Officer the reading of his Kollsman and was advised that it was minus 100 feet. A glance at the Captain's Kollsman revealed an identical reading. Holding the same rate of descent and air speed, the Captain continued his landing procedure and at the seventh light the aircraft connected the water going immediately into a water loop to the right. The Captain applied a hard left rudder and applied full throttle to the No. 4 engine, but he did not succeed in stopping the aircraft until it had turned about 180 degrees. The plane was examined and precautions were taken for caring for the passengers. Upon finding that the damage was negligible, the Captain turned the aircraft around and taxied it to the regular dock.

Subsequent investigation revealed that the conditions of the water and the wind at the time of this landing were not unusual. Following the landing, the true Kollsman reading was ascertained to be 30.22. This difference of .20 from the radioed setting of 30.02 is approximately equivalent to 200'. The error was on the safe (high) side; nevertheless the result was confusing to the pilot.

PROBABLE CAUSE:

Water loop.

CONTRIBUTING FACTORS:

1. Erroneous altimeter setting radioed to the approaching aircraft.

2. Pilot's error in judging altitude.