Engine failure

“ With such machines, which give us a first insight as to the aircraft of the future, engine failure begins to lose its perils—particularly in regard to war. More than once during the great campaign, when flying a single-engine machine, an aviator has found his motor fail him, and has been obliged to land on hostile soil ”

“ There are, of course, a great many other possibilities, but if these tests, carefully made, do not disclose the cause of the trouble, the novice had better send for a garage man. If one or two cylinders miss fire, the trouble is most likely to be caused through lack of compression278 or a short-circuited spark plug. If the engine refuses to run, the trouble is most likely to be due to lack of gasoline, or failure of battery or magneto. ”

“ It was evident that the damage to the engine was the result of the fatigue failure of the master rod. The failure apparently stopped the crankshaft so abruptly that the inertia of the propeller twisted off the nose section. The fuel characteristics were within proper limits and the condition of the sump and oil tank samples was not abnormal.
Disassembly and examination of the propeller by the Bureau of Standards revealed that the propeller was in normal operating condition up to the time of the powerplant failure, all damage to it being incurred by impact with the ground. ”

“ The best of them are liable to break down at the most needed moment, due to a hundred causes outside of the control of a mechanic or pilot. Care and rigid inspection will reduce the possibilities, but engine failure cannot yet be eliminated. ”

“ However, if an engine is operated at this higher horsepower for any continuous period of time, excessive temperature will be developed in the cylinder head, valves, pistons, etc., which may result in a failure of any one of these parts or seriously reduce the service life of the engine. Accordingly, engine operation limitations are specified by the Civil Aeronautics Administration in the operation record attached to the aircraft airworthiness certificate of each airplane. ”

“ An analysis of 40 British accidents shows 13 to have been due to engine failures, 10 to alighting on bad ground, 6 to wind gusts, 5 to breakage of the propeller, and 6 to fire and miscellaneous causes. These casualties were not all fatal, although the percentage of fatalities in aeronautic accidents is high. The most serious results were those due to alighting on bad ground; long grass and standing grain being very likely to trip the machine and throw the occupant. ”

“ If the engine runs regularly with all cylinders firing, then probably the exhaust is choked or the petrol supply fails. Failure of the petrol supply may be due to the use of too small a jet in the carburettor, too low a level in the float chamber, or to partial stoppage in the pipe line. Another cause of this trouble of intermittent running would sometimes be loss of battery power when using coil ignition, i.e., batteries want recharging. ”

“ Although two small pieces of rag, one 11⁄2 inches long and 1 inch wide and the other 3 inches long and 1⁄41/4 inch wide, were found in the carburetor grid, subsequent tests revealed that the presence of such rags in the grid would not cause any malfunctioning of the engines. The high tension lines and hills which surround the Charleston Municipal Airport are definite hazards [16] in case of a complete or partial power plant failure during a take-off toward the west or southwest in an air carrier airplane.
PROBABLE CAUSE:
Loss of power in the right engine due to causes unknown. ”

“ Failure of the captain to realize exhaustion of the gasoline supply as a probable cause of engine trouble, when that trouble was first experienced, and to turn the fuel selector valves to another tank in time to prevent complete failure of both engines. Low cruising altitude. Complete dependence of the operating personnel upon a fuel gauge for information as to the contents of the tanks, through failure to include in the flight-clearance routine any statement to the captain of the actual measured contents of each tank. ”

“ Since each engine has an independent oil system, the low pressure on the right engine could not have had any effect upon the left engine. It is not unusual for sludge or sediment to appear in airplane engines making it necessary that filters be installed in the lubricating system to prevent sludge from being directed through the smaller passages throughout the engine which might cause lubrication failure with resultant serious damage or failure to the engine. ”

“ The reliability of the modern air-cooled radial engine is so great that the chances of an immediate forced landing due to motor failure with a single motor, would in my opinion, be more than counterbalanced by the longer cruising range and consequent ability to reach the objective in the face of unfavorable conditions. ”

“ While there is a possibility of an inflight catastrophic problem with this engine, there is no evidence such as fire damage or shrapnel damage to the recovered portions of the engine cowling to support this possibility. Catastrophic engine failures ordinarily make themselves known through fire damage and puncture damage to the surrounding structure and the engine cowling. Also, the crew was conducting a radio conversation with approach control until just before the accident and gave no indication that any problem existed with the aircraft or any of its systems. ”

“ All fire damage to the engines occurred after impact. Except for No. 3 engine, which lay in a general ground-fire area, fire damage was localized and caused by spillage from broken fuel lines, fuel pumps, and fuel controls.
The engines and accessories were shipped to the American Airlines shop at Tulsa, Oklahoma, where they were disassembled. No evidence of operational failure or distress was revealed during the disassembly and examination. All engines were producing appreciable power at impact. Nos. 3 and 4 engines were more severely damaged by rotational interference than were Nos. ”

“ So far as the admission and exhaust valves are concerned, the wearing of the cams, rollers, and lever-pivots is evidenced by a retardation in the opening of these valves and an acceleration in their closing.
The ignition, whatever may be the system employed, is affected by lost motion and is retarded. The engine appreciably loses in power, and its consumption becomes excessive. ”

“ An engine will lose power through a defect of compression, carburetion, ignition, cooling or lubrication, or because of a mechanical fault.
If the trouble comes from cooling or lubrication, the engine will overheat and thus make the cause known. A bearing that binds will become very hot, while if the cooling system fails, the engine will be hot all over. When the engine is excessively hot, the pistons will [Pg 250] expand, and much of the power of the engine will be used up in forcing them to move. ”

“ But a difficulty arises with the internal combustion engine if the supply of mixture is similarly throttled, because a loss of quantity means loss of compression and bad ignition. Many oil engines are therefore governed by apparatus which, when the speed exceeds a certain limit, cuts off the supply altogether, either by throwing the oil-pump temporarily out of action, or by lifting the exhaust valve so that the movement of the piston causes no suction—the "hit-and-miss" method, as it is called. ”

“ Every precaution should be taken to locate the trouble when an engine shows a lack of power as it may be caused from the valve not seating properly, carbon in the cylinders, overheated engine, lack of lubrication, or the governor connection sticking. If lack of lubrication is causing the trouble it will soon lead to mechanical trouble such as scoring the cylinder walls or burning out the bearings. An engine will often give an apparent indication of a lack of power due to the brakes dragging or the clutch slipping. ”

“ If anything is due to the engine itself, in the vast majority of cases, it is due to poor compression. The engine is too often blamed for faults which belong elsewhere. Nevertheless, it is well carefully to examine the bearings, to look over the clutch, and the bearings in the line leading to the drive shaft.
Starting the Engine.—In starting, some engines give a great deal of trouble, usually due to wrong adjustment of the sparking device. This should not be advanced too much. If the trouble is not at that point, it may arise from too weak a suction, or an obstruction in the carbureter itself. ”

“ Have you ever stood on the front car platform of a train nearest to the engine and watched the jiggling draw-bar? It is apparently loose; its hold on the engine seems to be no more than that of the touch of clasped hands in a gipsy dance. Yet it never lets go, and the drag of it is always there. By and by, when the coal is all burned, and the fire is out, and the water is drained from the tank, those gentle little multiplied jerks will pull the big engine down—kill it—make it a mere mass of inert metal blocking the way of progress. ”

“ With machines built lightly, and subjected to heavy strains when at high speeds, it is vital that the inspection of such craft, that the examination of every detail of them, should be carried out in a spirit of the greatest care. The fraying through of a control wire, unnoticed by those in charge of a machine, has been sufficient to cause a disaster; while carelessness in overhauling a motor, a task of supreme importance, seeing that its engine is the heart of an aeroplane, has been another cause of accident. ”

“ If the pilot had inadvertently shut off the gasoline to the right engine or if there had been some other stoppage of the flow, the fuel pressure would have dropped and the fuel pressure warning light would have come on before the engine stopped. Based on the testimony of Captain Wright and First Officer Riley, it appears improbable that the right engine could have been cut off from the fuel supply by a maladjustment of the engine fuel selector valve. ”

“ The most vigilant and active attention on the part of every workman, however employed, in every part of the line, would therefore be necessary; but, independently of this, accidents arising from the fracture or derangement of any of the chains, or from the suspension of the working of any of the fixed engines, would be equally injurious, and (p. 169) would effectually stop the intercourse along the line. On the other hand, in locomotive engines an accident could only affect the particular train of carriages drawn by the engine to which the accident might occur ”

“ Faulty ignition may have its origin not only in the method of ignition employed, but also in excessive heating of the internal parts of the engine, caused by continual overloading or by inadequate circulation of water. ”

“ Furthermore, they are objectionable because the starting is effected too violently, and because the instantaneous explosion subjects the stationary piston, crank, and fly-wheel to a shock so sudden that they may be severely strained and may even break. Moreover, the slightest leakage in one of the valves or checks may cause the entire system to fail, and, particularly in the case of the pump, may induce a back explosion exceedingly dangerous to the man in charge of the engine. ”

“ The only danger that may be encountered is in starting the engine, filling the supply tank when a burner near at hand is in flame, etc. Once a gasoline engine is started and is supplied with gasoline, it may be left entirely alone without care for hours at a time without danger and without adjustment.
With a steam engine there is always danger, unless a highly skilled man is watching the engine every moment. If the water gets a little low he is liable to have an explosion; if it gets a little too high he may knock out a cylinder head in his engine ”

“ Cleanliness is a point that must be observed scrupulously; for spark-plugs are apt to foul only too readily, with the result that short-circuits and misfires are apt to occur. In oil and volatile hydrocarbon engines the tendency to fouling is particularly noticeable. In the chapter devoted [39] to these forms of motors the author has dwelt upon the precautions that should be taken to forestall a possible derangement of the ignition apparatus. As a general rule the ignition apparatus installed by trustworthy manufacturers will be found best suited for the requirements of the engine. ”

“ Water Lost.—If all the water has been lost on the road through the breakage of a pipe or the opening of a plug or tap, or loosening of a joint, and no water is near, you can continue your journey spasmodically by allowing the engine to cool down, then run on a mile or two with the bonnet open or off until it shows symptoms of overheating again, when stop, paraffin your cylinders, and wait another half-hour. The pump of a car has several times been known to have been carried away by contact with a dog ”

“ With engines that govern their speeds by throttling or by changing the quality of the mixture it is necessary for the best results, to vary the point of ignition with each quality of fuel that is admitted by the governor. The retard and advance of the ignition is very necessary on an automobile engine because of the throttling control and constant variation of the load and speed. All automobilists know of the heating troubles caused by running on a retarded spark. ”