[Federal Register Volume 59, Number 8 (Wednesday, January 12, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-700]


[[Page Unknown]]

[Federal Register: January 12, 1994]


                                                     VOL. 59, NO. 8

                                        Wednesday, January 12, 1994
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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-CE-58-AD]

 

Airworthiness Directives: Piper Aircraft Corporation Models PA34-
200, PA34-200T, PA34-220T, PA44-180, and PA44-180T Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to adopt a new airworthiness directive 
(AD) that would apply to certain Piper Aircraft Corporation (Piper) 
Models PA34-200, PA34-200T, PA34-220T, PA44-180, and PA44-180T 
airplanes. The proposed action would require repetitively inspecting 
the main landing gear trunnions for cracks, replacing any trunnions 
found cracked, and eventually replacing the landing gear trunnions with 
parts of improved design as terminating action for the repetitive 
inspection requirement. Several reports of the main landing gear 
trunnions cracking on the affected airplanes prompted the proposed 
action. The actions specified by the proposed AD are intended to 
prevent collapse of the main landing gear caused by cracked trunnions, 
which could result in airplane damage.

DATES: Comments must be received on or before March 14, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 93-CE-58-AD, room 1558, 601 E. 
12th Street, Kansas City, Missouri 64106. Comments may be inspected at 
this location between 8 a.m. and 4 p.m., Monday through Friday, 
holidays excepted.
    Service information that applies to the proposed AD may be obtained 
from the Piper Aircraft Corporation, Customer Services, 2926 Piper 
Drive, Vero Beach, Florida 32960. This information also may be examined 
at the Rules Docket at the address above.

FOR FURTHER INFORMATION CONTACT: Christina Marsh, Aerospace Engineer, 
FAA, Atlanta Aircraft Certification Office, 1669 Phoenix Parkway, suite 
210C, Atlanta, Georgia 30349; telephone (404) 991-2910; facsimile (404) 
991-3606.

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 should 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 that summarizes 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 No. 93-CE-58-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, Central Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 93-CE-58-AD, room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

Discussion

    Service history of certain Piper Models PA34-200, PA34-200T, PA34-
220T, PA44-180, and PA44-180T airplanes reveals several occurrences of 
cracked main landing gear (MLG) trunnions. Five of these occurrences 
resulted when the left MLG trunnion, part number (P/N) 67926-12, 
separated from Piper Model PA34-200T airplanes during the landing roll. 
Further investigation revealed that the left MLG collapsed because of a 
transverse fracture in the trunnion at the rear web lower end fillet. 
Metallurgical examination of four of these MLG trunnions further 
disclosed that the fractures originated from very shallow fatigue 
cracks originating from several areas along the rear surface at the 
lower end of the fillet web. The length of these fatigue cracks ranged 
from .20 to .40 inches.
    Piper has issued Service Bulletin (SB) 787B, dated August 25, 1993, 
which specifies procedures for inspecting the MLG trunnions on certain 
Piper Models PA34-200, PA34-200T, PA34-220T, PA44-180, and PA44-180T 
airplanes, and references replacing MLG trunnions with parts of 
improved design.
    After examining the circumstances and reviewing all available 
information related to the incidents described above including the 
referenced service information, the FAA has determined that AD action 
should be taken to prevent collapse of the main landing gear caused by 
cracked trunnions, which could result in airplane damage.
    Since an unsafe condition has been identified that is likely to 
exist or develop in other Piper Models PA34-200, PA34-200T, PA34-220T, 
PA44-180, and PA44-180T airplanes of the same type design, the proposed 
AD would require repetitively inspecting the main landing gear 
trunnions for cracks, replacing any trunnions found cracked, and 
eventually replacing the landing gear trunnions with parts of improved 
design as terminating action for the repetitive inspection requirement. 
The proposed inspections would be accomplished in accordance with Piper 
SB No. 787B, dated August 25, 1993. The proposed replacement would be 
accomplished in accordance with the applicable maintenance manual.
    The FAA estimates that 2,265 airplanes in the U.S. registry would 
be affected by the proposed AD, that it would take approximately 16 
workhours per airplane to accomplish the proposed initial inspection 
and replacement, and that the average labor rate is approximately $55 
an hour. Parts cost approximately $1,100 per airplane. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $4,484,700. This cost figure is based on the assumption 
that none of the affected airplane owners/operators have accomplished 
the proposed actions. The FAA believes that some airplane owners/
operators have already incorporated the inspection terminating MLG 
trunnion replacements. With this in mind, the FAA anticipates that the 
cost of the proposed AD would be much lower than the figure referenced 
above.
    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 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) 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 has been placed 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 14 
CFR part 39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

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

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

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

Piper Aircraft Corporation: Docket 93-CE-58-AD.

    Applicability: The following model and serial number airplanes 
that are not equipped with main landing gear (MLG) trunnions (both 
left and right side) that have either part number (P/N) 67926-30, 
67926-31, 67926-32, 67926-33, 39486-14, or 39486-15, as applicable, 
certificated in any category: 

------------------------------------------------------------------------
      Models                           Serial Numbers                   
------------------------------------------------------------------------
PA34-200..........  34-7250001 through 34-7450220                       
PA34-200T.........  34-7570001 through 34-8170092                       
PA34-220T.........  34-8133001 through 34-8233088                       
PA44-180..........  44-7995001 through 44-8195026, and 4495001 through  
                     4495013                                            
PA44-180T.........  44-8107001 through 44-8207020                       
------------------------------------------------------------------------

    Compliance: Required as indicated, unless already accomplished.
    To prevent collapse of the main landing gear caused by cracked 
trunnions, which could result in airplane damage, accomplish the 
following:

    Note 1: The paragraph structure of this AD is as follows:

Level 1: (a), (b), (c), etc.
Level 2: (1), (2), (3), etc.
Level 3: (i), (ii), (iii), etc.

Level 2 and Level 3 structures are designations of the Level 1 
paragraph they immediately follow.
    (a) Upon the accumulation of 500 hours time-in-service (TIS) on 
a MLG trunnion, dye-penetrant inspect the MLG trunnion for cracks in 
accordance with the INSTRUCTIONS section of Piper Service Bulletin 
(SB) 787B, dated August 25, 1993.

    Note 2: If hours TIS on the MLG trunnion are unknown, hours TIS 
accumulated on the airplane may be substituted.
    (1) For MLG trunnions found cracked, prior to further flight, 
replace the cracked MLG trunnion with a part of improved design, P/N 
67926-30, 67926-31, 67926-32, 67926-33, 39486-14, or 39486-15, as 
applicable, in accordance with the applicable maintenance manual.
    (2) For MLG trunnions not found cracked, reinspect at intervals 
not to exceed 100 hours TIS until the replacement specified in 
paragraph (b) of this AD is accomplished.
    (3) If one trunnion is found cracked and is replaced as 
specified in paragraph (a)(1) of this AD, the other trunnion must 
still be reinspected as specified in paragraph (a)(2) of this AD 
until it also is replaced.
    (b) Upon the accumulation of 2,000 hours TIS on a MLG trunnion, 
unless already accomplished as specified in paragraph (a)(1) of this 
AD, replace this MLG trunnion with a part of improved design, P/N 
67926-30, 67926-31, 67926-32, 67926-33, 39486-14, or 39486-15, as 
applicable, in accordance with the applicable maintenance manual.
    (1) If parts for any MLG replacement have been ordered from the 
manufacturer but are not available, prior to further flight and 
thereafter at intervals not to exceed 100 hour TIS, dye-penetrant 
inspect the MLG trunnion for cracks in accordance with the 
INSTRUCTIONS section of Piper Service Bulletin (SB) 787B, dated 
August 25, 1993. If any one of the following occurs, prior to 
further flight, terminate the above repetitive inspections and 
replace the trunnion as specified in paragraph (b) of this AD:
    (i) Parts become available;
    (ii) A trunnion is found cracked; or
    (iii) 2,500 hours TIS are accumulated on the trunnion.
    (2) Replacing both the left and right MLG trunnion with P/N 
67926-30, 67926-31, 67926-32, 67926-33, 39486-14, or 39486-15, as 
applicable, eliminates the inspection requirement of this AD.
    (c) Special flight permits may be issued in accordance with FAR 
21.197 and 21.199 to operate the airplane to a location where the 
requirements of this AD can be accomplished.
    (d) An alternative method of compliance or adjustment of the 
compliance time that provides an equivalent level of safety may be 
approved by the Manager, Atlanta Aircraft Certification Office 
(ACO),1669 Phoenix Parkway, Suite 210C, Atlanta, Georgia 30349. The 
request shall be forwarded through an appropriate FAA Maintenance 
Inspector, who may add comments and then send it to the Manager, 
Atlanta ACO.

    Note 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

    (e) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to the Piper Aircraft 
Corporation, 2926 Piper Drive, Vero Beach, Florida 32960; or may 
examine this document at the FAA, Central Region, Office of the 
Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri 64106.

    Issued in Kansas City, Missouri, on January 5, 1994.
Barry D. Clements,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 94-700 Filed 01-11-94; 8:45 am]
BILLING CODE 4910-13-U