[Federal Register Volume 63, Number 192 (Monday, October 5, 1998)]
[Rules and Regulations]
[Pages 53278-53279]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26603]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Parts 23, 25 and 33

[Docket No. 28652; Amendment Nos. 23-53, 25-95, and 33-19]
RIN 2120-AF75


Airworthiness Standards; Rain and Hail Ingestion Standards; 
Correction

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; correction.

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SUMMARY: This document corrects a final rule that was published in the 
Federal Register on March 26, 1998 (63 FR 14794). The final rule 
addressed engine power loss and instability phenomena attributed to 
operation in extreme rain or hail. Also, the final rule generally 
harmonized the Federal Aviation Administration and Joint Aviation 
Authorities rain and hail ingestion standards.

DATES: Effective October 5, 1998.

FOR FURTHER INFORMATION CONTACT: John Fisher, Burlington, Massachusetts 
01803-5229; telephone (781) 238-7149; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The Airworthiness Standards final rule on 
Rain and Hail Ingestion Standards, Docket No. 28652 was published in 
the Federal Register on March 26, 1998 (63 FR 14794). Under 
``Discussion of Comments,'' there is an incorrect phrase, and under 
Sec. 33.77 of the rule, the foreign object ingestion conditions table 
provides either misplaced or incorrect phrases.
    1. On page 14795, under ``Discussion of Comments,'' third column, 
third paragraph, nine lines down, the phrase ``Some amount of sustained 
power or thrust loss is permitted following an ice ingestion test'' 
should be replaced with ``Some amount of sustained power or thrust loss 
is permitted following testing to the new rain and hail ingestion 
standards, but no power or thrust loss is permitted following an ice 
ingestion test.''
    2. On page 14798, third column, under Sec. 33.77(e), the ingestion 
conditions table is corrected to read as follows:

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           Foreign object                    Test quantity           Speed of foreign object         Engine  operation                Ingestion
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BIRDS:
    3-ounce size....................  One for each 50 square       Liftoff speed of typical     Takeoff....................  In rapid sequence to
                                       inches of inlet area, or     aircraft.                                                 simulate flock encounter
                                       in fraction thereof, up to                                                             and aimed at selected
                                       a maximum of 16 birds.                                                                 critical areas.
                                       Three-ounce bird will pass
                                       the inlet guide vanes into
                                       the rotor blades.
    1\1/2\-pound size...............  One for the first 300        Initial climb speed of       Takeoff....................  In rapid sequence to
                                       square inches of inlet       typical aircraft.                                         simulate a flock encounter
                                       area, if it can enter the                                                              and aimed at selected
                                       inlet, plus one for each                                                               critical areas.
                                       additional 600 square
                                       inches of inlet area, or
                                       fraction, thereof up to a
                                       maximum of 8 birds.
    4-pound size....................  One, if it can enter the     Maximum climb speed of       Maximum cruise.............  Aimed at critical area.
                                       inlet..                      typical aircraft, if the
                                                                    engine has inlet guide
                                                                    vanes.
                                                                   Liftoff speed typical        Takeoff....................  Aimed at critical area.
                                                                    aircraft, if the engine
                                                                    does not have inlet guide
                                                                    vanes.
ICE.................................  Maximum accumulation on a    Sucked in..................  Maximum cruise.............  To simulate a continuous
                                       typical inlet cowl and                                                                 maximum icing encounter at
                                       engine face resulting from                                                             25  deg.F.
                                       a 2-minute delay in
                                       actuating anti-icing
                                       system, or a slab of ice
                                       which is comparable in
                                       weight or thickness for
                                       that size engine.
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Note: The term ``inlet area'' as used in this section means the engine inlet projected area at the front face of the engine. It includes the projected
  area of any spinner bullet nose that is provided.


[[Page 53279]]

    Issued in Washington, DC on September 30, 1998.
Donald P. Byrne,
Assistant Chief Counsel.
[FR Doc. 98-26603 Filed 10-2-98; 8:45 am]
BILLING CODE 4910-13-M