[Federal Register Volume 62, Number 17 (Monday, January 27, 1997)]
[Proposed Rules]
[Pages 3832-3834]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-1825]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-175-AD]
RIN 2120-AA64


Airworthiness Directives; Short Brothers Model SD3-30 and SD3-60 
Series Airplanes Equipped with Fire Fighting Enterprises (U.K.) Ltd. 
Fire Extinguishers

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 Shorts Model SD3-30 and SD3-60 
series airplanes equipped with certain fire extinguishers. This 
proposal would require replacement of the covers for fire extinguisher 
adapter assemblies that are installed on certain bulkheads with new 
covers that swivel to lock the extinguishers in place; and replacement 
of nozzles and triggers on these fire extinguishers with better fitting 
nozzles and stronger triggers. It also would require the installation 
of new fire extinguisher point placards and a revision of the Airplane 
Flight Manual to instruct the flight crew in the use of the new covers 
for these adapter assemblies. This proposal is prompted by reports that 
these fire extinguishers are not discharging properly because they do 
not fit correctly with the adapter, and that triggers on these 
extinguishers are failing. The actions specified by the proposed AD are 
intended to ensure that, in the event of fire in the baggage bay, 
extinguishing agent is properly distributed within this area, and 
portable extinguishers operate properly; and to prevent injury to crew 
and passengers when a portable extinguisher is discharged.

DATES: Comments must be received by March 7, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-175-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 Short Brothers PLC, 2011 Crystal Drive, Suite 713, 
Arlington, Virginia 22202-3719. This information may be examined at the 
FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, 
Washington.

FOR FURTHER INFORMATION CONTACT: Greg Dunn, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-2799; 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 Number 96-NM-175-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-175-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The FAA has received reports indicating that certain portable cabin 
fire extinguishers, manufactured by Fire Fighting Enterprises Ltd. and 
carried onboard all Shorts Model SD3-30 and SD3-60 series airplanes, 
may not work properly when installed on bulkheads separating the 
passenger cabin from the

[[Page 3833]]

aft and/or forward baggage bays. Because the nozzle of the extinguisher 
and the adapter do not fit together correctly, the extinguishing agent 
is ``blown back'' into the passenger cabin. This condition, if not 
corrected, could prevent adequate distribution of fire extinguishing 
agent within the baggage bay, and could cause injury to crew and 
passengers.
    The FAA also has received reports indicating that triggers on these 
fire extinguishers have failed because the operator did not lift the 
safety catch before squeezing the trigger; this caused the trigger to 
break at the neck of the actuating tang. This condition, if not 
corrected, could make the extinguisher unserviceable and, if broken 
during operation, could cause the extinguisher to fail, or cause a loss 
in the ability to control or stop discharge of the extinguishing agent.

Explanation of Relevant Service Information

    Short Brothers has issued Shorts Service Bulletin SD330-26-14, 
dated September 1994 (for Model SD3-30 series airplanes); and Service 
Bulletin SD360-26-11, dated July 1994 (for Model SD3-60 series 
airplanes). These service bulletins describe procedures for replacing 
the covers of the fire extinguisher adapter assemblies installed on 
bulkheads between the passenger cabin and baggage bays with new covers 
that swivel and lock the extinguishers in place. These service 
bulletins also describe procedures for installing new fire extinguisher 
point placards and revising the Airplane Flight Manual (AFM) to include 
instructions for the flight crew about using the new covers with the 
fire extinguishers.
    Fire Fighting Enterprises (U.K.) Ltd. has issued Service Bulletin 
26-107, Revision 1, dated November 2, 1992, which describes procedures 
for replacing the nozzles on portable cabin fire extinguishers having 
part number (P/N) BA51012SR-3 and BA51012SR. The replacement nozzles 
are chamfered, and fit more closely in the ``O'' ring of the bulkhead 
adapter; this will prevent ``blow back'' of the extinguishing agent 
when the extinguisher is used.
    In addition, Fire Fighting Enterprises (U.K.) Ltd. has issued 
Service Bulletin 26-108, dated September 1992, which describes 
procedures for replacing triggers on the discharge head assemblies of 
fire extinguishers carried on Shorts Model SD3-30 and SD3-60 series 
airplanes. The replacement trigger is manufactured from an improved and 
stronger material, and the radii around the neck of the actuating tang 
has been increased for additional strength.

Type Certification of Airplanes

    These airplane models are manufactured in the United Kingdom and 
type certificated for operation in the United States under the 
provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 
21.29) and the applicable bilateral airworthiness agreement.

Explanation of Requirements of Proposed Rule

    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require replacement of covers on fire extinguisher 
adapter assemblies on bulkheads between the passenger cabin and baggage 
bays with new covers that swivel and lock extinguishers in place. It 
would also require replacement of nozzles on these extinguishers with 
chamfered nozzles that fit better with these adapters; and replacement 
of triggers on these extinguishers with triggers made from improved and 
stronger materials.
    Additionally, this proposed AD would require installation of new 
fire extinguisher point placards, and a revision of the Limitations 
Section of the FAA-approved AFM to include instructions for the flight 
crew about using the new adapter assembly covers with the fire 
extinguishers.
    These actions would be required to be accomplished in accordance 
with the applicable service bulletins described previously.

Cost Impact

    The FAA estimates that 50 Model SD3-30 series airplanes of U.S. 
registry would be affected by this proposed AD. For these airplanes, it 
would take approximately 9 work hours per airplane to accomplish the 
proposed actions on airplanes with only a forward baggage bay, and 14 
work hours per airplane to accomplish the proposed actions on airplanes 
with forward and aft baggage bays. The average labor rate is $60 per 
work hour. Required parts would cost approximately $281 per airplane. 
Based on these figures, the cost impact of the proposed AD on U.S. 
operators of Model SD3-30 series airplanes is estimated to be between 
$41,050 and $56,050, or between $821 and $1,121 per airplane.
    The FAA estimates that 72 Model SD3-60 series airplanes of U.S. 
registry would be affected by this proposed AD. For these airplanes, it 
would take approximately 12 work hours per airplane to accomplish the 
proposed actions, at an average labor rate of $60 per work hour. 
Required parts would cost approximately $281 per airplane. Based on 
these figures, the cost impact of the proposed AD on U.S. operators of 
Model SD3-60 series airplanes is estimated to be $72,072, or $1,001 per 
airplane.
    The cost impact figures discussed above are 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.

[[Page 3834]]

Sec. 39.13  [Amended]

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

Short Brothers, PLC: Docket 96-NM-175-AD.

    Applicability: All Model SD3-30 and SD3-60 series airplanes 
equipped with fire extinguishers manufactured by Fire Fighting 
Enterprises (U.K.) Ltd.; 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 (d) 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 ensure that, in the event of fire, extinguishing agent is 
properly distributed within the baggage bays and portable 
extinguishers operate properly; and to prevent injury to crew and 
passengers, accomplish the following:
    (a) Within 6 months after the effective date of this AD, install 
a new cover on each fire extinguisher adapter assembly on bulkheads 
between the passenger cabin and aft and/or forward baggage bay, in 
accordance with Shorts Service Bulletin SD330-26-14, dated September 
1994 (for Shorts Model SD3-30 series airplanes), or Shorts Service 
Bulletin SD360-26-11, dated July 1994 (for Shorts Model SD3-60 
series airplanes), as applicable.
    (b) Prior to further flight after accomplishing the actions 
required by paragraph (a) of this AD, accomplish both paragraphs 
(b)(1) and (b)(2) of this AD:
    (1) Install new fire extinguisher point placards, in accordance 
with Shorts Service Bulletin SD330-26-14, dated September 1994 (for 
Shorts Model SD3-30 series airplanes), or Shorts Service Bulletin 
SD360-26-11, dated July 1994 (for Shorts Model SD3-60 series 
airplanes), as applicable. And
    (2) Revise the Limitations Section of the FAA-approved Airplane 
Flight Manual (AFM), in accordance with Note 1 of Paragraph 1.C. of 
Shorts Service Bulletin SD330-26-14, dated September 1994 (for 
Shorts Model SD3-30 series airplanes), or Shorts Service Bulletin 
SD360-26-11, dated July 1994 (for Shorts Model SD3-60 series 
airplanes), as applicable.
    (c) For airplanes equipped with fire extinguishers having part 
number (P/N) BA51012SR-3 or BA51012SR: Within 6 months after the 
effective date of this AD, accomplish either paragraph (c)(1) or 
(c)(2) of this AD:
    (1) Install a chamfered nozzle on the discharge head assembly of 
each fire extinguisher by replacing the discharge head assembly with 
a new discharge head assembly, having P/N BA22988-3, in accordance 
with Fire Fighting Enterprises (U.K.) Ltd. Service Bulletin 26-107, 
Revision 1, dated November 2, 1992. Or
    (2) Replace the trigger on the discharge head assembly of each 
fire extinguisher with a new trigger, in accordance with Fire 
Fighting Enterprises (U.K.) Ltd. Service Bulletin 26-108, dated 
September 1992. After replacement, install a chamfered nozzle on the 
discharge head assembly of each fire extinguisher by reworking the 
discharge head assembly in accordance with Fire Fighting Enterprises 
(U.K.) Ltd. Service Bulletin 26-107, Revision 1, dated November 2, 
1992
    (d) 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 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.

    (e) 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 January 17, 1997.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-1825 Filed 1-24-97; 8:45 am]
BILLING CODE 4910-13-U