[Federal Register Volume 78, Number 159 (Friday, August 16, 2013)]
[Proposed Rules]
[Pages 49982-49985]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-19926]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2013-0695; Directorate Identifier 2011-NM-264-AD]
RIN 2120-AA64


Airworthiness Directives; Saab AB, Saab Aerosystems Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for 
certain Saab AB, Saab Aerosystems Model 340A (SAAB/SF340A) and SAAB 
340B airplanes modified by Supplemental Type Certificate SA7971SW. This 
proposed AD was prompted by reports of smoke, a burning odor, and 
possible fire in the flight deck and cabin of the airplane, which was 
caused by brushes wearing beyond their limits, in the air conditioning 
motor. This proposed AD would require an inspection to determine if a 
certain air compressor motor is installed, an inspection to determine 
the age of a certain compressor hour meter since new or overhauled, and 
repetitive replacement of the brushes on affected air conditioning 
compressor motor units. As an option to the replacement, this proposed 
AD allows pulling the air conditioning circuit breaker and adding a 
placard. We are proposing this AD to detect and correct worn brushes 
contacting the commutator, which could result in a fire under the cabin 
floor with no means to detect or extinguish the fire.

DATES: We must receive comments on this proposed AD by September 30, 
2013.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE., Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

FOR FURTHER INFORMATION CONTACT: Gregory Thiele, Aerospace Engineer, 
Special Certification Office, ASW-190, FAA, 2601 Meacham Boulevard, 
Fort Worth, TX 76137; phone: (817) 222-5229; fax: (817) 222-5785; 
email: [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2013-0695; 
Directorate Identifier 2011-NM-264-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of this proposed AD. We 
will consider all comments received by the closing date and may amend 
this proposed AD because of those comments.
    We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We 
will also post a report summarizing each substantive verbal contact we 
receive about this proposed AD.

Discussion

    We received reports of smoke, a burning odor, and possible fire in 
the flight deck and cabin of the airplane, which was caused by brushes 
wearing beyond their limits, in the air conditioning motor. The rivets 
in the brush contacted the commutator, which caused sparks (the 
ignition source). The air conditioners (two units) are located under 
the floor, forward of the wing box. There is no fire detection or fire 
extinguishing equipment in the installed location. This condition (worn 
brushes contacting the commutator), if not corrected, could result in a 
fire under the cabin floor with no means to detect or extinguish the 
fire.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of these same type 
designs.

Proposed AD Requirements

    This proposed AD would require an inspection to determine if a 
certain air compressor motor is installed, an inspection to determine 
the age of a certain compressor hour meter since new or overhauled, and 
repetitive replacement of the brushes on affected air conditioning 
compressor motor units. As an option to the replacement, this proposed 
AD allows pulling the air conditioning circuit breaker and adding a 
placard. This proposed AD also requires sending the inspection results 
to the FAA.
    This proposed AD contains detailed steps to address the unsafe 
condition rather than referring to service information. However, under 
the provisions of paragraph (p) of this proposed AD, operators may 
request approval of an alternative method of compliance (AMOC), if 
sufficient data are submitted to substantiate that the AMOC would 
provide an acceptable level of safety.

Interim Action

    We consider this proposed AD interim action. The inspection reports 
that would be required by this proposed AD will enable us to obtain 
better insight into the nature, cause, and extent of the brush wear, 
and eventually to develop final action to address the unsafe condition. 
Once final action has been identified, we might consider further 
rulemaking.

Costs of Compliance

    We estimate that this proposed AD affects 23 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

[[Page 49983]]



                                                 Estimated Costs
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                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
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Inspection, drive motor assembly  11 work-hours x     $252 per            $1,187 per          $27,301 per
 brush replacement; and parts      $85 per hour =      replacement cycle.  replacement cycle.  replacement
 return and report.                $935 per                                                    cycle.
                                   replacement cycle.
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Paperwork Reduction Act Burden Statement

    A federal agency may not conduct or sponsor, and a person is not 
required to respond to, nor shall a person be subject to a penalty for 
failure to comply with a collection of information subject to the 
requirements of the Paperwork Reduction Act unless that collection of 
information displays a current valid OMB Control Number. The OMB 
Control Number for this information collection is 2120-0056. Public 
reporting for this collection of information is estimated to be 
approximately 5 minutes per response, including the time for reviewing 
instructions, completing and reviewing the collection of information. 
All responses to this collection of information are mandatory. Comments 
concerning the accuracy of this burden and suggestions for reducing the 
burden should be directed to the FAA at: 800 Independence Ave. SW., 
Washington, DC 20591, Attn: Information Collection Clearance Officer, 
AES-200.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII: Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701: ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This proposed regulation is 
within the scope of that authority because it addresses an unsafe 
condition that is likely to exist or develop on products identified in 
this rulemaking action.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. This proposed AD would not 
have a substantial direct effect 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.
    For the reasons discussed above, I certify 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),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

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

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

Saab AB, Saab Aerosystems: Docket No. FAA-2013-0695; Directorate 
Identifier 2011-NM-264-AD.

(a) Comments Due Date

    We must receive comments by September 30, 2013.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Saab AB, Saab Aerosystems Model 340A (SAAB/
SF340A) and SAAB 340B airplanes, certificated in any category, that 
have been modified as specified in Supplemental Type Certificate 
SA7971SW (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/CE3676EDFD53938785256CC20058E501?OpenDocument&Highlight=sa7971sw).

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 21, Air Conditioning.

(e) Unsafe Condition

    This AD was prompted by reports of smoke, a burning odor, and 
possible fire in the flight deck and cabin of the airplane, which 
were caused by brushes wearing beyond their limits, in the air 
conditioning motor. We are issuing this AD to detect and correct 
worn brushes contacting the commutator, which could result in a fire 
under the cabin floor with no means to detect or extinguish the 
fire.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Part Number (P/N) Inspection

    Within 30 days or 10 flight hours after the effective date of 
this AD, whichever occurs first: Inspect the air conditioner (A/C) 
compressor motor to determine if P/N 1134104-1 is installed. A 
review of airplane maintenance records is acceptable in lieu of this 
inspection if the part number of the A/C compressor motor can be 
conclusively determined from that review.

(h) Inspection of Compressor Hour Meter and Maintenance Records

    If, during the inspection required by paragraph (g) of this AD, 
any A/C compressor motor is found having P/N 1134104-1: Within 30 
days or 10 flight hours after the effective date of this AD, 
whichever occurs first, determine the hour reading on the A/C 
compressor hour meter as specified in paragraphs (h)(1) and (h)(2) 
of this AD.
    (1) Inspect the number of hours on the A/C compressor hour 
meter.
    (2) Check the airplane logbook for any entry for replacing the 
A/C compressor motor brushes with new brushes, or for replacing the 
compressor motor or compressor condenser module assembly (pallet) 
with a motor or assembly that has new brushes.
    (i) If the logbook contains an entry for replacement of parts as 
specified in paragraph (h)(2) of this AD, determine the number of 
hours on the A/C compressor motor brushes by comparing the number of 
hours on the compressor motor since replacement and use this number 
in lieu of the number determined in paragraph (h)(1) of this AD.

[[Page 49984]]

    (ii) If, through the logbook check, the number of hours on the 
A/C compressor motor brushes cannot be positively determined as 
specified in paragraph (h)(2) of this AD, use the number of hours on 
the A/C compressor hour meter determined in paragraph (h)(1) of this 
AD, or assume the brushes have over 500 hours time-in-service.

(i) Replacement

    Except as provided by paragraph (k) of this AD: Using the hour 
reading on the A/C compressor hour meter determined in paragraph (h) 
of this AD, replace the A/C compressor motor brushes with new 
brushes at the later of the times specified in paragraphs (i)(1) and 
(i)(2) of this AD. Thereafter, repeat the replacement of the A/C 
compressor motor brushes at intervals not to exceed every 500 hours 
time-in-service on the A/C compressor motor. Do the replacement in 
accordance with the actions specified in paragraph (j) of this AD.
    (1) Before or when the A/C compressor motor reaches a total of 
500 hours time-in-service. Or,
    (2) Before further flight after the inspection required by 
paragraph (h) of this AD.

(j) Motor Brush Replacement Instructions

    Do the actions specified in paragraphs (j)(1) through (j)(23) of 
this AD to replace the compressor motor brushes as required by 
paragraph (i) of this AD:
    (1) New brushes may be installed by first level maintenance 
personnel only under the conditions listed in paragraphs (j)(1)(i) 
through (j)(1)(iv) of this AD. If these conditions are not met, 
deactivate the A/C in accordance with paragraph (k)(1) of this AD 
until the conditions listed in paragraphs (j)(1)(i) through 
(j)(1)(iv) of this AD are met, or the entire compressor motor is 
replaced.
    (i) Motor was operating correctly prior to brush replacement.
    (ii) The motor is tested to verify proper operation and does not 
show any defects that would require motor replacement.
    (iii) Only approved vendor brushes are used (P/N 1251171).
    (iv) Brushes are installed, seated, and tested in accordance 
with paragraphs (j)(2) through (j)(23) of this AD.
    (2) Verify all electrical power is off to the system.
    (3) Remove all access panels and exhaust ducts to gain access to 
the drive motor.
    (4) Disconnect power leads from motor terminals (1/4-28). Tag 
the positive lead.
    (5) Remove condenser support bracket to provide access to brush 
cover fasteners and remove motor cuff shroud.
    (6) Loosen and unsnap brush cover assembly. Remove from the 
motor.
    (7) Verify all power is off, and that all panels, shrouds, 
brackets, and fairings are removed.
    (8) With a stiff wire hook or scribe, lift brush spring from 
holder and remove each worn brush set until all four sets are 
removed.
    (9) Remove brush shunt wire terminal screw. Continue this step 
until all four screws are removed.
    (10) With brushes removed and using shop air at 30-40 pounds per 
square inch gauge (psig) and nozzle, blow out as much carbon and/or 
copper dust as possible from the commutator, armature, and field 
windings. Purge from the commutator end of the motor.
    (11) Install each new brush set by lifting brush springs, 
sliding brush into holder (with brush leading edge in direction of 
motor rotation) and lightly releasing the brush spring on the brush. 
(See Figure 1 to paragraph (m)(2)(vii) of this AD). CAUTION: Do not 
allow brush spring to strike hard into place or damage to brush may 
result.
    (12) Verify that the brush seats flat on the commutator and that 
no binding in the holder is present. Align brush spring in center of 
brush groove.
    (13) Install terminal screw and lock washer on brush shunt lead 
and other leads and tighten. Repeat this step for other brush sets. 
Torque to 15-20 in.-lbs. CAUTION: Do not cross thread or over torque 
brush lead screws or thread damage may result.
    (14) Seat new brushes in accordance with paragraph (j)(15) of 
this AD. All new brushes must be seated to assure proper motor 
operation and/or performance.
    (15) Brush Seating Procedure: Cut a 7 inch long by 1.5 inch wide 
(0.125 inch, both dimensions) strip of 400-500 grit sand 
paper and place, with rough side out, on commutator. Secure one end 
of the paper to the commutator with masking tape in a manner such 
that the taped end will lead in the direction of shaft rotation 
(counter-clockwise looking at fan end). The other end will remain 
loose and overlap the taped end. Raise each brush momentarily while 
rotating the shaft until the taped end passes under each brush. 
After the sand paper is properly located tight against the 
commutator and encompasses all brush surface areas, carefully rotate 
the armature, by hand, in the normal direction of rotation until a 
full seat is obtained on each new brush. Three or four rotations is 
usually adequate. Excessive seating is not advised. Brush life may 
be reduced.
    (16) Remove sand paper and blow out all carbon dust from the 
commutator and brush area. CAUTION: Eye, nose and throat protection 
must be worn during this procedure.
    (17) Carefully lay brush shunt leads in position such as to 
prevent any shorting problems. Leads must be able to easily follow 
brush and spring movement as brush wear occurs.
    (18) Replace brush cover and attach motor power cables, if 
required.
    (19) Replace all bracketry and hardware removed to access motor.
    (20) Assure that brackets are properly installed, cooling fan 
does not interfere with shroud, motor drive belt aligned/tensioned, 
and belt cover is installed.
    (21) The motor should be tested to verify proper operation. 
Therefore, connect ground power source or verify aircraft power is 
on and turn system on.
    (22) Run system for a minimum of 15 minutes to seat brushes and 
check motor operation.
    (23) Turn system and aircraft power off. System is ready for 
use.

(k) Deactivation/Reactivation

    (1) In lieu of replacing the A/C compressor motor brushes as 
required by paragraphs (i) and (j) of this AD, before further 
flight, deactivate the A/C by doing the actions specified in 
paragraph (k)(1)(i) or (k)(1)(ii) of this AD, as applicable.
    (i) Single System: Pull the compressor control circuit breaker 
(cockpit right-hand 10VU panel, ``REAR AIR COND''); install a 
placard by the A/C selection switch (co-pilot's side panel) 
prohibiting use of the air conditioner; and document deactivation of 
the system in the airplane logbook referring to this AD as the 
reason for deactivation.
    (ii) Dual System: Pull the compressor control circuit breakers 
(cockpit right-hand 10VU panel, ``REAR AIR COND,'' and cockpit left-
hand 9VU panel, ``FWD AIR COND''); install a placard (or placards) 
by the A/C selection switches (co-pilot's side panel) prohibiting 
use of the air conditioners; and document deactivation of the system 
in the airplane logbook referring to this AD as the reason for 
deactivation.
    (2) If an operator chooses to deactivate the system and then 
later chooses to return the airplane to service: Before returning 
the A/C system to service and removing the placard(s), do the 
inspection specified in paragarph (g) of this AD, and, as 
applicable, the inspection specified in paragraph (h) of this AD, 
and the replacements specified in paragraph (i) of this AD at the 
times specified in paragraph (i) of this AD.

(l) Parts Installation Limitation

    As of the effective date of this AD, no person may install an A/
C compressor motor having P/N 1134104-1 on any airplane, unless the 
inspection specified in paragraph (h) of this AD has been done, and 
the replacements specified in paragraph (i) of this AD are done at 
the times specified in paragraph (i) of this AD.

(m) Reporting Requirement

    Submit a report of the results of the determination of hours 
required by paragraph (h) of this AD to the Special Certification 
Office, ASW-190, Attn: Gregory Thiele, Aerospace Engineer, 2601 
Meacham Boulevard, Fort Worth, TX 76137; or email to: [email protected]. The report must include the information specified in 
paragraphs (m)(1) through (m)(4) of this AD.
    (1) The model and serial number of the airplane.
    (2) The elapsed amount of flight hours since the last brush/
motor replacement, if known.
    (3) The amount of hours on the hour meter of the A/C compressor 
motor.
    (4) The amount of wear on the brushes (including overall length 
and total calculated wear), calculated as specified in paragraphs 
(m)(4)(i) through (m)(4)(ix) of this AD.
    (i) Verify all electrical power is off to system.
    (ii) Remove all access panels and exhaust ducts to gain access 
to the drive motor.
    (iii) Disconnect power leads from motor terminals (1/4-28). Tag 
positive lead.
    (iv) Remove condenser support bracket to provide access to brush 
cover fasteners and remove motor cuff shroud.

[[Page 49985]]

    (v) Loosen and unsnap brush cover assembly. Remove from motor.
    (vi) With wire hook or scribe, lift brush spring and remove 
brush.
    (vii) Measure each brush as shown in figure below and record 
values.
[GRAPHIC] [TIFF OMITTED] TP16AU13.010

    (viii) Using the brush with the shortest measured length 
calculate the wear by subtracting the measured value from 1.000 
inch.
    (ix) Replace brushes in accordance with the instructions 
specified in paragraphs (j)(9) through (j)(23) of this AD.

(n) Reporting Compliance Time

    Submit the report required by paragraph (m) of this AD at the 
applicable time specified in paragraph (m)(1) or (m)(2) of this AD.
    (1) If the determination of hours was done on or after the 
effective date of this AD: Submit the report within 30 days after 
the inspection.
    (2) If the determination of hours was done before the effective 
date of this AD: Submit the report within 30 days after the 
effective date of this AD.

(o) Special Flight Permit

    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 an appropriately rated repair 
station, provided that the A/C is deactivated as specified in 
paragraph (k)(1) of this AD on airplanes on which the A/C has been 
operated for 500 hours or more, and replacement brushes are not 
available.

(p) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Special Certification Office, ASW-190, FAA, has 
the authority to approve AMOCs for this AD, if requested using the 
procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, 
send your request to your principal inspector or local Flight 
Standards District Office, as appropriate. If sending information 
directly to the manager of the Special Certification Office, send it 
to the attention of the person identified in the Related Information 
section of this AD.
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(q) Related Information

    For more information about this AD, contact Gregory Thiele, 
Aerospace Engineer, Special Certification Office, ASW-190, FAA, 2601 
Meacham Boulevard, Fort Worth, TX 76137; phone: (817) 222-5229; fax: 
(817) 222-5785; email: [email protected].

    Issued in Renton, Washington, on August 9, 2013.
Jeffrey E. Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-19926 Filed 8-15-13; 8:45 am]
BILLING CODE 4910-13-P