Accident Report

Public Safety and Accidents Investigation Committee.

—On the motion of Mr. G. B. Cockburn, the following reports of the Public Safety and Accidents Investigation Committee were unanimously adopted :—

REPORT ON THE FATAL ACCIDENT TO CAPT. PATRICK HAMILTON AND L I E U T. A. WYNESS-STUART, WHEN FLYING AT GRAVELEY, NEAR STEVENAGE, HERTS, ON FRIDAY, SEPTEMBER 6TH, 1912, AT ABOUT 7.15 A.M.

Brief Description of the Accident

Capt. Patrick Hamilton, with Lieut. A. Wyness-Stuart as passenger, flying on a French Deperdussin two-seater monoplane, fitted with a 100-h.p. Gnome engine, left Wallingford on the morning of September 6th, 1912, for work in connection with the Army Manoeuvres. When approaching Hitchin from the direction of Graveley, the aircraft was observed to become unsteady, shortly afterwards the wing to break, and the aircraft to fall to the ground. The aviator and his passenger were both killed instantaneously.

Capt. Patrick Hamilton was granted his Aviator's Certificate No. 194, on March 12th, 1912, and Lieut. A. Wyness- Stuart, No. 141, on September 26th, 1911, by the Royal Aero Club.

Report.—The Committee met on Tuesday, October 22nd, 1912, Wednesday, January 1st, and Monday, January 6th, 1913. The representatives of the British Deperdussin Aeroplane Company, Ltd., attended, and produced plans of the aircraft and gave evidence on various points raised by the Committee.

From the consideration of the evidence the Committee regards the following facts as clearly established : —

(1) That this aircraft was built in France about May, 1912. It had taken part in the Military Aeroplane Competition on Salisbury Plain during the month of August, 1912, and had been awarded the Second Prize of £2,000 in the Competition open to the world. It was subsequently purchased and taken over by the Government.

(2) That when the wing broke the aircraft fell from a height of at least 500 ft. from the ground.

(3) That the aircraft struck the ground nearly vertically and nose first, its fall being broken by a high hedge and bank, in such a manner that no parts of it could have been projected more than a few feet after it struck the ground.

(4) That parts of the structure of the aircraft, viz., an aluminium plate from the left wing spar, some pieces of the cabane struts, the cowl which covers the engine, and also parts of the engine, viz., two push rods, were nevertheless found some 600 feet away from the spot where the aircraft struck the ground, and somewhat to the right of the direction from which the aircraft was seen to come.

(5) That some part or parts of the engine, whilst revolving, had been in contact with the interior surface of the cowl or cover which is fitted over the upper portion of the engine, and that eight of the push rods had been broken off close to the crank-case of the engine.

(6) That the bolts which attached the outside cable to the underside of the front spar of the left wing sheared in the air.

(7) That a piece of the propeller was missing from one of the blades and has never been found.

(8) That the engine was overhung and not fitted with the front bearing recommended by the makers for this type.

(9) That the front strut of the cabane was supported above the engine.

Opinion.—The Committee is of opinion that the collapse of the aircraft was due to the breaking of the outer wires supporting the left wing by a derangement of the cabane whilst in flight, caused either by :—

(a) the fouling of the cowl by a valve-rocker owing to the fracture of a valve tappet, or

(b) the partial failure or breakage of the propeller which, throwing the rotating system out of balance, caused severe racking stresses and strained the attachments of the engine to such an extent that they ultimately gave way and the engine shifted. The engine attachments were too light for the engine.

Recommendation.—The Committee draws the attention of manufacturers, designers, and aviators to the risk involved by want of provision against the consequences of possible failure of parts of the engine or its attachments to the aircraft, when such failure would lead to the breakage of other and vital parts of the structure