[Federal Register Volume 62, Number 84 (Thursday, May 1, 1997)]
[Proposed Rules]
[Pages 23695-23697]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: X97-10501]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-NM-167-AD]
RIN 2120-AA64


Airworthiness Directives; Saab Model SAAB 2000 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 certain Saab Model SAAB 2000 
series airplanes. This proposal would require replacement of the 
existing fire, tailpipe, and bleed-air overheat detector control units 
with new, improved units. This proposal is prompted by reports 
indicating that false engine and auxiliary power unit (APU) fire 
warnings were issued from the fire detector control units due to 
moisture or induced voltages of the detector control unit. The actions 
specified by the proposed AD are intended to prevent such false fire 
warnings, which could result in unnecessary diversion of the airplane, 
and resultant increased risks to the airplane, passengers, and crew, 
and the potential for an overweight landing.

DATES: Comments must be received by June 12, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Transport Airplane Directorate, ANM-103, 
Attention: Rules Docket No. 96-NM-167-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 SAAB Aircraft AB, SAAB Aircraft Product Support, S-
581.88, Linkoping, Sweden. This information may be examined at the FAA, 
Transport

[[Page 23696]]

Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT: Ruth Harder, Aerospace Engineer, 
Standardization Branch, ANM-113, FAA, Transport Airplane Directorate, 
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206) 
227-1721; 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-167-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-167-AD, 1601 Lind Avenue, SW., Renton, Washington 
98055-4056.

Discussion

    The Luftfartsverket (LFV), which is the airworthiness authority for 
Sweden, recently notified the FAA that an unsafe condition may exist on 
certain Saab Model SAAB 2000 series airplanes. The LFV advises that it 
has received reports indicating that false engine and auxiliary power 
unit (APU) fire warnings were issued from the fire detector control 
units on these airplanes. Investigation has revealed that the false 
engine and APU fire warnings were caused by moisture or induced 
voltages of the overheat detector wires, which resulted in false input 
signals to the fire detector control units. Additionally, the 
investigation revealed that moisture or induced voltages also caused 
false warnings of the tailpipe and bleed-air overheat detection control 
units.
    Such moisture or induced voltages of the fire detector control 
units, if not corrected, could cause false fire warnings of the engine 
or APU during flight; false fire warnings could result in unnecessary 
diversion of the airplane, and resultant increased risks to the 
airplane, passengers, and crew, and the potential for an overweight 
landing.

Explanation of Relevant Service Information

    Saab has issued Service Bulletin 2000-26-002, dated May 9, 1995, 
which describes procedures for replacement of the fire, tailpipe, and 
bleed leak detector control units with new, improved units. These new, 
improved control units contain new software that give fire warnings 
only when a fire or overheat condition occurs. The LFV classified this 
service bulletin as mandatory and issued Swedish Airworthiness 
Directive (SAD) No. 1-073, dated May 10, 1995, in order to assure the 
continued airworthiness of these airplanes in Sweden.

FAA's Conclusions

    This airplane model is manufactured in Sweden and is 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. Pursuant to this 
bilateral airworthiness agreement, the LFV has kept the FAA informed of 
the situation described above. The FAA has examined the findings of the 
LFV, reviewed all available information, and determined that AD action 
is necessary for products of this type design that are certificated for 
operation in the United States.

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 replacement of the 
existing fire, tailpipe, and bleed leak detector control units with 
new, improved units. The actions would be required to be accomplished 
in accordance with the service bulletin described previously.

Cost Impact

    The FAA estimates that 2 Saab Model SAAB 2000 series airplanes of 
U.S. registry would be affected by this proposed AD, that it would take 
approximately 3 work hours per airplane to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would be provided by the manufacturer at no cost to the 
operators. Based on these figures, the cost impact of the proposed AD 
on U.S. operators is estimated to be $360, or $180 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:

[[Page 23697]]

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:

Saab Aircraft AB: Docket 96-NM-167-AD.

    Applicability: Model SAAB 2000 series airplanes having serial 
numbers 005 through 029 inclusive, 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 (c) 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 false fire warning inputs of the engines and 
Auxiliary Power Unit (APU), which could result in unnecessary 
diversion of the airplane, resultant increased risks to the 
airplane, passengers, and crew, and the potential for an overweight 
landing; accomplish the following:
    (a) Within 4 months after the effective date of this AD, replace 
the existing fire (engine/APU), tailpipe, and bleed-air overheat 
detector control units with new, improved control units, in 
accordance with Saab Service Bulletin 2000-26-002, dated May 9, 
1995.
    (b) As of the effective date of this AD, no person shall install 
a fire, tailpipe, or bleed-air detector control unit having part 
number 25000020-21, 25000021-31, or 25000020-11, on any airplane.
    (c) 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.

    (d) 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 April 25, 1997.
Neil D. Schalekamp,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Dos. 97-11333 Filed 4-30-97; 8:45 am]
BILLING CODE 4910-13-U