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ornia. The airplane was received from the manufacturer by the Pennsylvania-Central Airlines Corporation on May 25, 1940. It was powered with two Wright Cyclone engines, Model G-102-A, each rated at 1100 horsepower for take off and was equipped with Hamilton Standard constant speed, hydromatic, full-feathering propellers, 11 feet 6 inches in diameter, Hub Models 23 E 50 and Blade Models 6153A. This type of aircraft, equipped with engines and propellers as above described, has been extensively and successfully used in commercial air transportation in this country and abroad for a number of years.
The records of the company show that the total flying time for aircraft NC 21789 and its engines and propellers at the time the airplane left the Washington-Hoover Airport on August 31, 1940, was 565 hours and 54 minutes. The overhaul period on this type engine prescribed by the Authority for Pennsylvania-Central Airlines is 600 hours.
The airplane arrived 11:00 a.m. on Saturday, August 31, 1940, after having completed a shheduled flight from Detroit, Michigan. Nothing unusual was reported concerning its operation on this trip nor had anything unusual or any mechanical defect or adjustment of more than a minor nature, been reported with respect to any previous trip.
Following its arrival in Washington, the airplane was serviced with gasoline and oil and was given a routine "turn-around" inspection. This inspection consists of a general visual examination of the airplane, especially of the propellers, wing and tail surfaces, and the controls which are visible from the outside, and the testing of the controls, engines, instruments, and radio equipment. In addition, the interior of the airplane is cleaned and the outside surfaces wiped off. The record
