[Federal Register Volume 62, Number 29 (Wednesday, February 12, 1997)]
[Proposed Rules]
[Pages 6504-6505]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-3435]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 96-NM-180-AD]
RIN 2120-AA64


Airworthiness Directives; Raytheon Model BAe 125-1000A and Model 
Hawker 1000 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to all Raytheon Model BAe 125-1000A 
and Model Hawker 1000 series airplanes. This proposal would require 
various modifications to increase the size of certain existing pressure 
venting areas and to add additional venting areas. This proposal is 
prompted by results of a design review of the requirements for 
certification of the cabin pressurization system. The actions specified 
by the proposed AD are intended to prevent inadequate venting of cabin 
pressure in the event of rapid decompression, which could cause failure 
or deformation of certain structural members, and consequent reduced 
controllability of the airplane.

DATES: Comments must be received by March 24, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-180-AD, 1601 Lind Avenue, SW., 
Renton, Washington 98055-4056. Comments may be inspected at this 
location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except 
Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from Raytheon Aircraft Company, Manager Service Engineering, 
Hawker Customer Support Department, P.O. Box 85, Wichita, Kansas 67201-
0085. This information may be examined at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: William Schroeder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2148; fax (206) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications shall identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number96-NM-180-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules 
Docket No. 96-NM-180-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has reviewed results of a design review of requirements for 
certification of the cabin pressurization system on Raytheon Model BAe 
125 and Model Hawker 1000 series airplanes. The Civil Aviation 
Authority (the airworthiness authority for the United Kingdom) and the 
manufacturer (Raytheon) conducted the design review, and determined 
that the existing venting between certain structural members is 
inadequate to provide rapid equalization of the pressure differential 
between the two sides of these members when rapid decompression occurs 
on one side of the member. Inadequate venting of cabin pressure, if not 
corrected, could cause failure or deformation of certain structural 
members, and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

    The FAA has reviewed and approved the following Raytheon Service 
Bulletins:
    1. Service Bulletin SB.21-151-25A683C, dated July 12, 1994 
(Modification 25A683C), which describes procedures for installing a 
pressure relief flap in the rear luggage compartment of the bulkhead at 
frame 19. Installation of the pressure relief flap will limit the 
pressure differential across the rear luggage compartment in the event 
of rapid decompression of the airplane.
    2. Service Bulletin SB.53-81-3661B, dated February 25, 1994 
(Modification 253661B), which describes procedures to remove the 
fiberglass infill cover located outboard of the floor panels between 
frame 8 and frame 10B. This service bulletin also describes procedures 
to increase the existing size of the lightening holes in the rail web 
of the right-hand seat between frame 10B and frame 10D, and to add a 
third hole to increase the vent area. Additionally, the service 
bulletin describes procedures for installation of a new reinforcing 
plate for all three lightening holes. Accomplishment of this 
modification will ensure the structural integrity of the fuselage in 
the event of rapid decompression of the airplane.
    3. Service Bulletin SB.53-76-3627A, dated February 25, 1994 
(Modification

[[Page 6505]]

253627A), which describes procedures for adding two holes to the 
underfloor diaphragm at frame 10D (right-hand). Accomplishment of these 
procedures increases the vent area between the cabin and the right-hand 
underfloor area by 4 square inches. Accomplishment of this modification 
will ensure the continued structural integrity of the fuselage in the 
event of rapid decompression of the airplane.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other airplanes of the same type design registered 
in the United States, the proposed AD would require:
    1. installing a pressure relief flap in the rear luggage 
compartment of the bulkhead at frame 19;
    2. enlarging two lightening holes and adding one new lightening 
hole in the rail web of the right seat between frames 10B and 10D, and 
removing fiberglass fill from the right support structure between frame 
8 and frame 10B; and
    3. installing two new vent holes in the underfloor diaphragm of 
frame 10D (right hand).
    The actions would be required to be accomplished in accordance with 
the service bulletins described previously.

Cost Impact

    The FAA estimates that 31 Model BAe 125-1000A and Model Hawker 1000 
series airplanes of U.S. registry would be affected by this proposed 
AD, that it would take approximately 44 work hours per airplane to 
accomplish the proposed actions, and that the average labor rate is $60 
per work hour. Based on these figures, the cost impact of the proposed 
AD on U.S. operators is estimated to be $81,840, or $2,640 per 
airplane.
    The cost impact figure discussed above is based on assumptions that 
no operator has yet accomplished any of the proposed 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 proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

Raytheon Aircraft Company (Formerly Beech, Raytheon Corporate Jets, 
British Aerospace, Hawker Siddeley, et al): Docket 96-NM-180-AD.

    Applicability: All Model BAe 125-1000A and Model Hawker 1000 
series airplanes, 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 (b) 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.
    Note 2: Raytheon Model BAe 125-1000B series airplanes are 
similar in design to the airplanes that are subject to the 
requirements of this AD and, therefore, also may be subject to the 
unsafe condition addressed by this AD. However, as of the effective 
date of this AD, those models are not type certificated for 
operation in the United States. Airworthiness authorities of 
countries in which Model BAe 125-1000B series airplanes are approved 
for operation should consider adopting corrective action, applicable 
to those models, that is similar to the corrective action required 
by this AD.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent inadequate venting of cabin pressure in the event of 
rapid decompression, which could cause failure or deformation of 
certain structural members, and consequent reduced controllability 
of the airplane, accomplish the following:
    (a) Within 8 months after the effective date of this AD, 
accomplish the requirements of paragraphs (a)(1), (a)(2), and (a)(3) 
of this AD.

    Note 3: The manufacturer has advised that the modifications 
required by paragraphs (a)(2) and (a)(3) of this AD should be 
incorporated concurrently.

    (1) Install a pressure relief flap in the rear luggage 
compartment of the bulkhead at frame 19 (Modification No. 25A683C), 
in accordance with Raytheon Service Bulletin SB.21-151-25A683C, 
dated July 12, 1994.
    (2) Enlarge two lightening holes, and add one new lightening 
hole in the rail web of the right-hand seat between frames 10B and 
10D, and remove the fiberglass infill cover located outboard of the 
floor panels between frame 8 and frame 10B (Modification 
SB.253661B), in accordance with Raytheon Service Bulletin SB.53-81-
3661B, dated February 25, 1994.
    (3) Install two new vent holes in the underfloor diaphragm of 
frame 10D (Modification 253627A), in accordance with Raytheon 
Service Bulletin SB.53-76-3627A, dated February 25, 1994.
    (b) 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, 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 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Standardization Branch, ANM-113.

    (c) 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.

    Issued in Renton, Washington, on February 5, 1997.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-3435 Filed 2-11-97; 8:45 am]
BILLING CODE 4910-13-U