§ 33.37 14 CFR Ch. I (1–1–10 Edition) all attitudes that the applicant estab- installation on the engine must be es- lishes as those the engine can have tablished and recorded. when the aircraft in which it is in- [Amdt. 33–6, 39 FR 35465, Oct. 1, 1974] stalled is in the static ground attitude. (e) If provided as part of the engine, § 33.43 Vibration test. the applicant must show for each fluid (a) Each engine must undergo a vi- injection (other than fuel) system and bration survey to establish the tor- its controls that the flow of the in- sional and bending vibration character- jected fluid is adequately controlled. istics of the crankshaft and the pro- [Doc. No. 3025, 29 FR 7453, June 10, 1964, as peller shaft or other output shaft, over amended by Amdt. 33–10, 49 FR 6851, Feb. 23, the range of crankshaft speed and en- 1984] gine power, under steady state and transient conditions, from idling speed § 33.37 Ignition system. to either 110 percent of the desired 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 cylinder 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 propeller 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 (a) The lubrication system of the en- test. gine must be designed and constructed (b) The torsional and bending vibra- so that it will function properly in all tion stresses of the crankshaft and the flight attitudes and atmospheric condi- propeller shaft or other output shaft tions in which the airplane is expected may not exceed the endurance limit to operate. In wet sump engines, this stress of the material from which the requirement must be met when only shaft is made. If the maximum stress one-half of the maximum lubricant in the shaft cannot be shown to be supply is in the engine. below the endurance limit by measure- 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 Subpart D—Block Tests; occur within the endurance limit stress Reciprocating Aircraft Engines of the material. (c) Each accessory drive and mount- § 33.41 Applicability. ing attachment must be loaded, with 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. (d) The vibration survey described in § 33.42 General. paragraph (a) of this section must be Before each endurance test required repeated with that cylinder not firing by this subpart, the adjustment setting which has the most adverse vibration and functioning characteristic of each effect, in order to establish the condi- component having an adjustment set- tions under which the engine can be op- ting and a functioning characteristic erated safely in that abnormal state. that can be established independent of However, for this vibration survey, the 852 VerDate Nov<24>2008 10:44 Mar 02, 2010 Jkt 220043 PO 00000 Frm 00862 Fmt 8010 Sfmt 8010 Y:\SGML\220043.XXX 220043 erowe on DSK5CLS3C1PROD with CFR Federal Aviation Administration, DOT § 33.49 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. Measurements taken during the final (b) Unsupercharged engines and en- portion of the endurance test may be gines incorporating a gear-driven single- used in showing compliance with the speed supercharger. For engines not in- requirements of this paragraph. corporating a supercharger and for en- 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- § 33.47 Detonation test. nate periods of 5 minutes at rated take- Each engine must be tested to estab- off power with takeoff speed, and 5 lish that the engine can function with- minutes at maximum best economy out detonation throughout its range of cruising power or maximum rec- intended conditions of operation. ommended cruising power. (2) A 20-hour run consisting of alter- § 33.49 Endurance test. nate periods of 11⁄2 hours at rated max- (a) General. Each engine must be sub- imum continuous power with max- jected to an endurance test that in- imum continuous speed, and 1⁄2 hour at cludes a total of 150 hours of operation 75 percent rated maximum continuous (except as provided in paragraph power and 91 percent maximum contin- (e)(1)(iii) of this section) and, depend- uous speed. ing upon the type and contemplated (3) A 20-hour run consisting of alter- use of the engine, consists of one of the nate periods of 11⁄2 hours at rated max- series of runs specified in paragraphs imum continuous power with max- (b) through (e) of this section, as appli- imum continuous speed, and 1⁄2 hour at cable. The runs must be made in the 70 percent rated maximum continuous order found appropriate by the Admin- power and 89 percent maximum contin- istrator for the particular engine being uous speed. 853 VerDate Nov<24>2008 10:44 Mar 02, 2010 Jkt 220043 PO 00000 Frm 00863 Fmt 8010 Sfmt 8010 Y:\SGML\220043.XXX 220043 erowe on DSK5CLS3C1PROD with CFR.