Federal Aviation Administration, DOT § 33.43

applicant must show that foreign par- § 33.42 General. ticles passing through the prescribed Before each endurance test required filtering means will not critically im- by this subpart, the adjustment setting pair engine fuel system functioning. and functioning characteristic of each (d) Each passage in the induction sys- component having an adjustment set- tem that conducts a mixture of fuel ting and a functioning characteristic and air must be self-draining, to pre- that can be established independent of vent a liquid lock in the cylinders, in installation on the engine must be es- all attitudes that the applicant estab- tablished and recorded. lishes as those the engine can have [Amdt. 33–6, 39 FR 35465, Oct. 1, 1974] when the aircraft in which it is in- stalled is in the static ground attitude. § 33.43 Vibration test. (e) If provided as part of the engine, (a) Each engine must undergo a vi- the applicant must show for each fluid bration survey to establish the tor- injection (other than fuel) system and sional and bending vibration character- its controls that the flow of the in- istics of the and the pro- jected fluid is adequately controlled. peller shaft or other output shaft, over [Doc. No. 3025, 29 FR 7453, June 10, 1964, as the range of crankshaft speed and en- amended by Amdt. 33–10, 49 FR 6851, Feb. 23, gine power, under steady state and 1984] transient conditions, from idling speed to either 110 percent of the desired § 33.37 . maximum continuous speed rating or Each spark ignition engine must 103 percent of the maximum desired have a dual ignition system with at takeoff speed rating, whichever is high- least two spark plugs for each er. The survey must be conducted and two separate electric circuits with using, for airplane engines, the same separate sources of electrical energy, configuration of the type or have an ignition system of equiva- which is used for the endurance test, lent in-flight reliability. and using, for other engines, the same configuration of the loading device § 33.39 Lubrication system. type which is used for the endurance test. (a) The lubrication system of the en- (b) The torsional and bending vibra- gine must be designed and constructed tion stresses of the crankshaft and the so that it will function properly in all propeller shaft or other output shaft flight attitudes and atmospheric condi- may not exceed the endurance limit tions in which the airplane is expected stress of the material from which the to operate. In wet sump engines, this shaft is made. If the maximum stress requirement must be met when only in the shaft cannot be shown to be one-half of the maximum lubricant below the endurance limit by measure- supply is in the engine. ment, the vibration frequency and am- (b) The lubrication system of the en- plitude must be measured. The peak gine must be designed and constructed amplitude must be shown to produce a to allow installing a means of cooling stress below the endurance limit; if the lubricant. not, the engine must be run at the con- (c) The crankcase must be vented to dition producing the peak amplitude the atmosphere to preclude leakage of until, for steel shafts, 10 million stress oil from excessive pressure in the reversals have been sustained without crankcase. fatigue failure and, for other shafts, until it is shown that fatigue will not occur within the endurance limit stress Subpart D—Block Tests; of the material. Reciprocating Aircraft Engines (c) Each accessory drive and mount- ing attachment must be loaded, with § 33.41 Applicability. the loads imposed by each accessory This subpart prescribes the block used only for an aircraft service being tests and inspections for reciprocating the limit load specified by the appli- aircraft engines. cant for the drive or attachment point.

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(d) The vibration survey described in (e)(1)(iii) of this section) and, depend- paragraph (a) of this section must be ing upon the type and contemplated repeated with that cylinder not firing use of the engine, consists of one of the which has the most adverse vibration series of runs specified in paragraphs effect, in order to establish the condi- (b) through (e) of this section, as appli- tions under which the engine can be op- cable. The runs must be made in the erated safely in that abnormal state. order found appropriate by the Admin- However, for this vibration survey, the istrator for the particular engine being engine speed range need only extend tested. During the endurance test the from idle to the maximum desired engine power and the crankshaft rota- takeoff speed, and compliance with tional speed must be kept within ±3 paragraph (b) of this section need not percent of the rated values. During the be shown. runs at rated takeoff power and for at [Amdt. 33–6, 39 FR 35465, Oct. 1, 1974, as least 35 hours at rated maximum con- amended by Amdt. 33–10, 49 FR 6851, Feb. 23, tinuous power, one cylinder must be 1984] operated at not less than the limiting temperature, the other cylinders must § 33.45 Calibration tests. be operated at a temperature not lower (a) Each engine must be subjected to than 50 degrees F. below the limiting the calibration tests necessary to es- temperature, and the oil inlet tempera- tablish its power characteristics and ture must be maintained within ±10 de- the conditions for the endurance test grees F. of the limiting temperature. specified in § 33.49. The results of the An engine that is equipped with a pro- power characteristics calibration tests peller shaft must be fitted for the en- form the basis for establishing the durance test with a propeller that characteristics of the engine over its thrust-loads the engine to the max- entire operating range of crankshaft imum thrust which the engine is de- rotational speeds, manifold pressures, signed to resist at each applicable op- fuel/air mixture settings, and altitudes. erating condition specified in this sec- Power ratings are based upon standard tion. Each accessory drive and mount- atmospheric conditions with only those ing attachment must be loaded. During accessories installed which are essen- operation at rated takeoff power and tial for engine functioning. rated maximum continuous power, the (b) A power check at sea level condi- load imposed by each accessory used tions must be accomplished on the en- only for an aircraft service must be the durance test engine after the endur- limit load specified by the applicant ance test. Any change in power charac- for the engine drive or attachment teristics which occurs during the en- point. durance test must be determined. (b) Unsupercharged engines and en- Measurements taken during the final gines incorporating a gear-driven single- portion of the endurance test may be speed . For engines not in- used in showing compliance with the corporating a supercharger and for en- requirements of this paragraph. gines incorporating a gear-driven sin- [Doc. No. 3025, 29 FR 7453, June 10, 1964, as gle-speed supercharger the applicant amended by Amdt. 33–6, 39 FR 35465, Oct. 1, must conduct the following runs: 1974] (1) A 30-hour run consisting of alter- nate periods of 5 minutes at rated take- § 33.47 Detonation test. off power with takeoff speed, and 5 Each engine must be tested to estab- minutes at maximum best economy lish that the engine can function with- cruising power or maximum rec- out detonation throughout its range of ommended cruising power. intended conditions of operation. (2) A 20-hour run consisting of alter- nate periods of 11⁄2 hours at rated max- § 33.49 Endurance test. imum continuous power with max- (a) General. Each engine must be sub- imum continuous speed, and 1⁄2 hour at jected to an endurance test that in- 75 percent rated maximum continuous cludes a total of 150 hours of operation power and 91 percent maximum contin- (except as provided in paragraph uous speed.

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