[Federal Register Volume 61, Number 221 (Thursday, November 14, 1996)]
[Rules and Regulations]
[Pages 58326-58327]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-28871]


-----------------------------------------------------------------------


DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-40-AD; Amendment 39-9813; AD 96-23-08]
RIN 2120-AA64


Airworthiness Directives; British Aerospace Model BAe 146 Series 
Airplanes and Model Avro 146-RJ Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to certain British Aerospace Model BAe 146 and Model Avro 
146-RJ series airplanes, that requires repetitive tests of the 
integrity of the electrical circuit between the windshear computer and 
the flap position sensor, and repair of the electrical wiring, if 
necessary. This amendment also requires replacement of certain 
windshear computers with new computers, which, when accomplished, 
terminates the repetitive tests. This amendment is prompted by a report 
indicating that the existing windshear computer is not capable of 
detecting a signal indicating loss of flap position; this could result 
in the flightcrew following erroneous computer-generated guidance. The 
actions specified by this AD are intended to prevent the incapability 
of the windshear computer to detect the true flap position, which, if 
not corrected, could result in the inability of the flightcrew to avoid 
a windshear encounter, and consequent reduced controllability of the 
airplane.

DATES: Effective December 19, 1996.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 19, 1996.

ADDRESSES: The service information referenced in this AD may be 
obtained from British Aerospace Regional Aircraft Limited, Avro 
International Aerospace Division, Customer Support, Woodford Aerodrome, 
Woodford, Cheshire SK7 1QR, England. This information may be examined 
at the Federal Aviation Administration (FAA), Transport Airplane 
Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Tim Backman, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2797; fax (206) 227-1149.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to certain British Aerospace Model 
BAe 146 and Model Avro 146-RJ series airplanes was published in the 
Federal Register on August 26, 1996 (61 FR 43692). That action proposed 
to require repetitive tests of the integrity of the electrical circuit 
between the windshear computer and the flap position sensor, and repair 
of the electrical wiring, if necessary. That action also proposed to 
require replacement of existing windshear computers with new safe 
flight windshear computers.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the single comment received.
    The commenter supports the proposed rule.

Conclusion

    After careful review of the available data, including the comment 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.

Cost Impact

    The FAA estimates that 41 British Aerospace Model BAe 146 series 
airplanes and Model Avro 146-RJ series airplanes of U.S. registry will 
be affected by this AD, that it will take approximately 1 work hour per 
airplane to accomplish the required actions, and that the average labor 
rate is $60 per work hour. Based on these figures, the cost impact of 
the AD on U.S. operators is estimated to be $2,460, or $60 per 
airplane, per test cycle.
    The FAA estimates that it will take approximately 4 work hours per 
airplane to accomplish the proposed replacement, at an average labor 
rate of $60 per work hour. Required parts will be supplied by the 
manufacturer at no cost to operators. Based on these figures, the cost 
impact of the replacement on U.S. operators is estimated to be $9,840, 
or $240 per airplane.
    The cost impact figures discussed above are based on assumptions 
that no operator has yet accomplished any of the requirements of this 
AD action, and that no operator would accomplish those actions in the 
future if this AD were not adopted.

Regulatory Impact

    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

[[Page 58327]]

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

96-23-08 British Aerospace: Amendment 39-9813. Docket 96-NM-40-AD.

    Applicability: Model BAe 146 and Model Avro 146-RJ series 
airplanes on which BAe Modification HCM40270A or HCM40270B (Safe 
Flight Windshear Computer) has been installed, certificated in any 
category.

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For airplanes that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (e) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent the inability of the flightcrew to avoid a windshear 
encounter and consequent reduced controllability of the airplane due 
to the inability of the windshear computer to detect the true flap 
position, accomplish the following:
    (a) Within 300 landings or 60 days after the effective date of 
this AD, whichever occurs first: Perform a test of the integrity of 
the electrical circuit between the windshear computer and the flap 
position sensor, in accordance with Avro International Aerospace 
Alert Inspection Service Bulletin S.B. 34-A155, Revision 2, dated 
August 9, 1995. Repeat the test thereafter at intervals not to 
exceed 300 landings until the actions required by paragraph (c) of 
this AD are accomplished.
    (b) If any test required by paragraph (a) of this AD fails, 
prior to further flight, repair the electrical wiring in accordance 
with Avro International Aerospace Alert Inspection Service Bulletin 
S.B. 34-A155, Revision 2, dated August 9, 1995. Thereafter, repeat 
the test required by paragraph (a) of this AD at intervals not to 
exceed 300 landings until the actions required by paragraph (c) of 
this AD are accomplished.
    (c) Within 6 months after the effective date of this AD: Replace 
any Safe Flight windshear computer having part number 6508-2 or 
6508-4 with a new Safe Flight windshear computer having part number 
6508-5; and change the polarity of the polarizing keys; in 
accordance with British Aerospace Modification Service Bulletin 
SB.34-160-70548A, dated November 21, 1994. Accomplishment of these 
actions constitutes terminating action for the repetitive tests 
required by paragraph (a) of this AD.
    (d) As of the effective date of this AD, no person shall install 
a Safe Flight windshear computer having part number 6508-2 or 6508-4 
on any airplane.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Manager, Standardization Branch, 
ANM-113, FAA, Transport Airplane Directorate. Operators shall submit 
their requests through an appropriate FAA Principal Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Standardization Branch, ANM-113.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.
    (g) The actions shall be done in accordance with Avro 
International Aerospace Alert Inspection Service Bulletin S.B. 34-
A155, Revision 2, dated August 9, 1995; or British Aerospace 
Modification Service Bulletin SB.34-160-70548A, dated November 21, 
1994; as applicable. Avro International Aerospace Alert Inspection 
Service Bulletin S.B.34-A155, Revision 2, dated August 9, 1995, 
contains the following list of specified effective pages:

------------------------------------------------------------------------
                                 Revision                               
           Page No.            level shown       Date shown on page     
                                 on page                                
------------------------------------------------------------------------
1, 2.........................            2  August 9, 1995.             
3-5..........................            1  September 10, 1993.         
------------------------------------------------------------------------

    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from British Aerospace Regional 
Aircraft Limited, Avro International Aerospace Division, Customer 
Support, Woodford Aerodrome, Woodford, Cheshire SK7 1QR, England. 
Copies may be inspected at the FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (h) This amendment becomes effective on December 19, 1996.
    Issued in Renton, Washington, on November 5, 1996.

Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-28871 Filed 11-13-96; 8:45 am]
BILLING CODE 4910-13-U