14 CFR 33.77 - Foreign object ingestion

§ 33.77 Foreign object ingestion—ice.
(a) -(b) [Reserved]
(c) Ingestion of ice under the conditions of paragraph (e) of this section may not—
(1) Cause a sustained power or thrust loss; or
(2) Require the engine to be shutdown.
(d) For an engine that incorporates a protection device, compliance with this section need not be demonstrated with respect to foreign objects to be ingested under the conditions prescribed in paragraph (e) of this section if it is shown that—
(1) Such foreign objects are of a size that will not pass through the protective device;
(2) The protective device will withstand the impact of the foreign objects; and
(3) The foreign object, or objects, stopped by the protective device will not obstruct the flow of induction air into the engine with a resultant sustained reduction in power or thrust greater than those values required by paragraph (c) of this section.
(e) Compliance with paragraph (c) of this section must be shown by engine test under the following ingestion conditions:
(1) Ice quantity will be the maximum accumulation on a typical inlet cowl and engine face resulting from a 2-minute delay in actuating the anti-icing system; or a slab of ice which is comparable in weight or thickness for that size engine.
(2) The ingestion velocity will simulate ice being sucked into the engine inlet.
(3) Engine operation will be maximum cruise power or thrust.
(4) The ingestion will simulate a continuous maximum icing encounter at 25 degrees Fahrenheit.
[Doc. No. 16919, 49 FR 6852, Feb. 23, 1984, as amended by Amdt. 33-19, 63 FR 14798, Mar. 26, 1998; 63 FR 53278, Oct. 5, 1998; Amdt. 33-20, 65 FR 55856, Sept. 14, 2000]
Beta! The text on the eCFR tab represents the unofficial eCFR text at ecfr.gov.
§ 33.77 Foreign object ingestion - ice.

(a) Compliance with the requirements of this section must be demonstrated by engine ice ingestion test or by validated analysis showing equivalence of other means for demonstrating soft body damage tolerance.

(b) [Reserved]

(c) Ingestion of ice under the conditions of this section may not -

(1) Cause an immediate or ultimate unacceptable sustained power or thrust loss; or

(2) Require the engine to be shutdown.

(d) For an engine that incorporates a protection device, compliance with this section need not be demonstrated with respect to ice formed forward of the protection device if it is shown that -

(1) Such ice is of a size that will not pass through the protective device;

(2) The protective device will withstand the impact of the ice; and

(3) The ice stopped by the protective device will not obstruct the flow of induction air into the engine with a resultant sustained reduction in power or thrust greater than those values defined by paragraph (c) of this section.

(e) Compliance with the requirements of this section must be demonstrated by engine ice ingestion test under the following ingestion conditions or by validated analysis showing equivalence of other means for demonstrating soft body damage tolerance.

(1) The minimum ice quantity and dimensions will be established by the engine size as defined in Table 1 of this section.

(2) The ingested ice dimensions are determined by linear interpolation between table values, and are based on the actual engine's inlet hilite area.

(3) The ingestion velocity will simulate ice from the inlet being sucked into the engine.

(4) Engine operation will be at the maximum cruise power or thrust unless lower power is more critical.

Table 1 - Minimum Ice Slab Dimensions Based on Engine Inlet Size

Engine Inlet Hilite area
(sq. inch)
Thickness
(inch)
Width
(inch)
Length
(inch)
0 0.25 0 3.6
80 0.25 6 3.6
300 0.25 12 3.6
700 0.25 12 4.8
2800 0.35 12 8.5
5000 0.43 12 11.0
7000 0.50 12 12.7
7900 0.50 12 13.4
9500 0.50 12 14.6
11300 0.50 12 15.9
13300 0.50 12 17.1
16500 0.5 12 18.9
20000 0.5 12 20.0
[Doc. No. 16919, 49 FR 6852, Feb. 23, 1984, as amended by Amdt. 33-19, 63 FR 14798, Mar. 26, 1998; 63 FR 53278, Oct. 5, 1998; Amdt. 33-20, 65 FR 55856, Sept. 14, 2000; Amdt. 33-34, 79 FR 65537, Nov. 4, 2014]

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

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United States Code

Title 14 published on 2015-01-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 14 CFR Part 33 after this date.

  • 2015-11-20; vol. 80 # 224 - Friday, November 20, 2015
    1. 80 FR 72561 - Special Conditions: CFM International, LEAP-1B Engine Models; Incorporation of Woven Composite Fan Blades
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      DEPARTMENT OF TRANSPORTATION, Federal Aviation Administration
      Final special conditions; request for comments.
      The effective date of these special conditions is December 21, 2015. We must receive your comments by December 7, 2015.
      14 CFR Parts 33 and 35