[Federal Register Volume 62, Number 203 (Tuesday, October 21, 1997)]
[Proposed Rules]
[Pages 54595-54598]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-27794]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-CE-69-AD]
RIN 2120-AA64


Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly 
Piper Aircraft Corporation), Models PA-31, PA-31-300, PA-31-325, PA-31-
350, PA-31P, PA-31T, and PA-31T1 Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede Airworthiness Directive 
(AD) 80-26-05, which currently requires the following on certain The 
New Piper Aircraft, Inc. (Piper) Models PA-31, PA-31-300, PA-31-325, 
PA-31-350, PA-31P, PA-31T, and PA-31T1 airplanes: repetitively 
inspecting the main landing gear (MLG) inboard door hinges and 
attachment angles for cracks, and replacing any cracked MLG inboard 
door hinge or attachment angle. The proposed AD results from the 
Federal Aviation Administration's policy on aging commuter-class 
aircraft and the determination that an improved design MLG inboard door 
hinge and attachment assembly (or approved hinges and angles made of 
steel), when incorporated, will eliminate the need for the currently 
required repetitive short-interval inspections. The proposed AD would 
retain the current repetitive inspections contained in AD 80-26-05, and 
would require installing these improved design or approved steel parts 
as terminating action for the repetitive inspection requirement. The 
actions specified in the proposed AD are intended to prevent separation 
of the MLG inboard door from the airplane caused by a cracked inboard 
door hinge or attachment angle, which could result in the MLG becoming 
jammed with consequent loss of control of the airplane during landing 
operations.

DATES: Comments must be received on or before December 26, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 96-CE-69-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 relates to the proposed AD may be obtained 
from The New Piper Aircraft, Inc., 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, One Crown Center, 1895 
Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone (770) 
703-6079; facsimile (770) 703-6097.

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. 96-CE-69-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 Regional Counsel, Attention: 
Rules Docket No. 96-CE-69-AD, Room 1558, 601 E. 12th Street, Kansas 
City, Missouri 64106.

Discussion

    On December 1, 1995, the FAA issued a proposal to amend part 39 of 
the Federal Aviation Regulations (14 CFR part 39) to include an AD that 
would apply to Piper Models PA-31, PA-31-325, PA-31-350, PA-31P, PA-
31T, and PA-31T1 airplanes. This proposal was published in the Federal 
Register as a notice of proposed rulemaking (NPRM) on December 7, 1995 
(60 FR 62774), and proposed to supersede AD 80-26-05, Amendment 39-
3994. The NPRM proposed to (1) retain the requirement of repetitively 
inspecting the main landing gear (MLG) inboard door hinges and 
attachment angles for cracks, and replacing any cracked MLG inboard 
door hinge or attachment angle; and (2) require incorporating a MLG 
inboard

[[Page 54596]]

door hinge and attachment angle assembly of improved design (part 
number 47529-32) or FAA-approved hinges and angles made of steel, as 
terminating action for the repetitive inspection requirement. 
Accomplishment of the proposed inspections would have been in 
accordance with Piper Service Bulletin (SB) No. 682, dated July 24, 
1980.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration was given to the one 
comment received.

Explanation of the Comment Received on the NPRM

    The comment received on the NPRM contained information that the 
improved design hinge assemblies, part number (P/N) 47529-32, are also 
susceptible to fatigue cracking, and that installing this assembly 
should not eliminate the need for the repetitive inspections currently 
required by AD 80-26-05. The commenter states that its airplane fleet 
has experienced three failures and three incidents related to fatigue 
cracking of the P/N 47529-32 hinge assemblies.

Subsequent Actions

    The FAA conducted a review of the manufacturer's service history 
and service difficulty reports in the FAA database associated with the 
P/N 47529-32 MLG inboard door hinge assembly. Based on a review of this 
information, including the information received from the commenter, the 
FAA determined that more information and analysis were needed before 
MLG inboard door hinge assembly replacements were mandated through an 
AD, as terminating action for the repetitive inspections currently 
required by AD 80-26-05.
    With the above information in mind, the FAA issued, on February 11, 
1997, an advance notice of proposed rulemaking (ANPRM) to provide an 
opportunity for the general public to participate in the decision as to 
what course of rulemaking the FAA should take. The ANPRM was published 
in the Federal Register on February 19, 1997 (62 FR 7375). At this 
time, the FAA also withdrew the NPRM.
    Interested persons were encouraged to provide information that 
describes what they consider the best action (if any) to be taken 
regarding the P/N 47529-32 MLG hinge assembly. No information or 
comments were received on the ANPRM.

The FAA's Analysis and Determination

    The FAA service difficulty database contains 10 reports of failure 
or cracks found in the MLG inboard door hinge assembly on the affected 
airplanes. Six of these reports were submitted by the commenter to the 
NPRM, with three of these incidents attributed to the original MLG 
inboard door hinge assemblies. The other four reports are not clear as 
to whether the original MLG inboard door hinge assemblies were 
installed or the improved design assemblies were installed. However, 
the incidents occurred on high service time airplanes and, since there 
is no AD action mandating the installation of the improved design MLG 
inboard door hinge assemblies, the FAA presumes that the original hinge 
assemblies were installed.
    The FAA has reviewed the three incident reports on the improved 
design MLG inboard door hinge assemblies and performed extensive 
testing and analysis of the improved design MLG inboard door hinge 
assemblies. The FAA has determined that the incidents were isolated and 
that mandating repetitive inspections is not needed when the P/N 47529-
32 MLG inboard door hinge assemblies are installed. The FAA has 
determined that Piper Model PA-31-300 airplanes incorporate the same 
type design as the other PA-31 series airplanes and could incorporate 
the same part number MLG inboard door hinge assemblies.
    After reviewing all available information related to this subject, 
including the referenced service information, the FAA has determined 
that AD action should be taken to (1) eliminate the repetitive short-
interval inspections required by AD 80-26-05; and (2) prevent 
separation of a MLG door from the airplane caused by a cracked inboard 
door hinge or attachment angle, which could result in the MLG becoming 
jammed with consequent loss of control of the airplane during landing 
operations.

Explanation of the Provisions of the Proposed AD

    Since an unsafe condition has been identified that is likely to 
exist or develop in other Piper Models PA-31, PA-31-300, PA-31-325, PA-
31-350, PA-31P, PA-31T, and PA-31T1 airplanes of the same type design, 
the FAA is proposing an AD. The proposed AD would supersede AD 80-26-05 
with a new AD that would (1) retain the requirement of repetitively 
inspecting the MLG inboard door hinges and attachment angles for 
cracks, and replacing any cracked MLG inboard door hinge or attachment 
angle; and (2) require incorporating a MLG inboard door hinge and 
attachment angle assembly of improved design (part number 47529-32) or 
FAA-approved hinges and angles made of steel, as terminating action for 
the repetitive inspection requirement. Accomplishment of the proposed 
inspections would be in accordance with Piper SB No. 682, dated July 
24, 1980.

The FAA's Aging Commuter-Class Aircraft Policy

    The actions proposed in this AD are part of the FAA's aging 
commuter-class aircraft policy, which briefly states that, when a 
modification exists that could eliminate or reduce the number of 
required critical inspections, the modification should be incorporated. 
This policy is based on the FAA's determination that reliance on 
critical repetitive inspections on aging commuter-class airplanes 
carries an unnecessary safety risk when a design change exists that 
could eliminate or, in certain instances, reduce the number of those 
critical inspections. In determining what inspections are critical, the 
FAA considers (1) the safety consequences of the airplane if the known 
problem is not detected by the inspection; (2) the reliability of the 
inspection such as the probability of not detecting the known problem; 
(3) whether the inspection area is difficult to access; and (4) the 
possibility of damage to an adjacent structure as a result of the 
problem.
    The alternative to installing the improved design hinge assemblies 
on the affected airplanes would be to rely on the repetitive 
inspections required by AD 80-26-05 to detect cracks in these areas.

Cost Impact

    The FAA estimates that 1,769 airplanes in the U.S. registry would 
be affected by the proposed AD, that it would take approximately 2 
workhours per airplane to accomplish the proposed replacement, and that 
the average labor rate is approximately $60 an hour. Parts cost 
approximately $2,000 per airplane ($500 per assembly  x  4 assemblies 
per airplane). Based on these figures, the total cost impact of the 
proposed AD on U.S. operators is estimated to be $3,750,280 or $2,120 
per airplane. This figure is based on the presumption that no affected 
airplane owner/operator has accomplished the proposed replacement.
    Piper has informed the FAA that hinge assemblies have been 
distributed to equip approximately 400 (1,600

[[Page 54597]]

separate assemblies) of the affected airplanes. Presuming that 400 of 
the affected airplanes have four of these hinge assemblies 
incorporated, the cost impact of the proposed AD upon U.S. owners 
operators of the affected airplanes would be reduced by $848,000 from 
$3,750,280 to $2,902,280.
    The intent of the FAA's aging commuter airplane program is to 
ensure safe operation of commuter-class airplanes that are in 
commercial service without adversely impacting private operators. The 
FAA believes that a large number of the remaining 1,369 affected 
airplanes (1,769 affected airplanes--400 airplanes) that would be 
affected by the proposed AD are operated in various types of air 
transportation. This includes scheduled passenger service, air cargo, 
and air taxi.
    The proposed AD would allow 800 hours time-in-service (TIS) after 
the effective date of the proposed AD before mandatory accomplishment 
of the design modification. The average utilization of the fleet for 
those airplanes in air transportation is between 25 to 40 hours TIS per 
week. Based on these figures, operators of commuter-class airplanes 
involved in commercial operation would have to accomplish the proposed 
modification within 5 to 8 months after the proposed AD would become 
effective. For private owners, who typically operate between 100 to 200 
hours TIS per year, this would allow 4 to 8 years before the proposed 
modification would be mandatory.

Compliance Time of the Proposed AD

    The FAA established the 800 hours TIS replacement compliance time 
based on its engineering evaluation of the problem. Among the issues 
examined in this engineering evaluation were analysis of service 
difficulty reports, the difficulty level of the inspection, and how 
critical the situation would be if cracks occurred in the subject area 
despite accomplishment of the repetitive inspections.
    Usually, the FAA establishes the mandatory design modification 
compliance time on AD's affecting aging commuter-class airplanes upon 
the accumulation of a certain number of hours TIS on the airplane. For 
this action, the FAA is proposing to mandate the modification for all 
operators ``within the next 800 hours TIS after the effective date of 
this AD.'' The total TIS levels of the airplane fleet vary from under 
1,000 hours TIS to over 5,000 hours TIS, and annual accumulation rates 
vary from 50 hours TIS to over 1,000 hours TIS. Establishing a long-
term set compliance time of hours TIS accumulated on Piper Models PA-
31, PA-31-300, PA-31-325, PA-31-350, PA-31P, PA-31T, and PA-31T1 
airplanes (such as 5,000 hours TIS) would impose an undue burden on the 
manufacturer of having to maintain a supply of replacement parts for 
the entire fleet when many airplanes in the fleet may never reach this 
compliance time.
    Instead, the FAA believes that Piper should maintain parts for 
several years; in this case about 8 years to allow low-usage airplanes 
time to accumulate the 800 hours after the effective date of the AD. 
The FAA has determined that the compliance time of the proposed rule 
provides the level of safety required for commuter air service and 
general aviation, while still minimizing the impact on the private 
airplane owners of Piper Models PA-31, PA-31-300, PA-31-325, PA-31-350, 
PA-31P, PA-31T, and PA-31T1 airplanes.

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 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 
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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(AD) 80-26-05, Amendment 39-3994, and by adding a new AD to read as 
follows:

The New Piper Aircraft, Inc. (formerly Piper Aircraft Corporation): 
Docket No. 96-CE-69-AD. Supersedes AD 80-26-05, Amendment 39-3994.
    Applicability: The following model and serial number airplanes, 
certificated in any category, that are not equipped with Piper part 
number (P/N) 47529-32 main landing gear (MLG) inboard door hinge 
assemblies or FAA-approved MLG inboard door hinges and attachment 
angles made of steel at all four hinge assembly locations:

------------------------------------------------------------------------
                Models                           Serial numbers         
------------------------------------------------------------------------
PA-31, PA-31-300, and PA-31-325.......  31-2 through 31-8012077.        
PA-31-350.............................  31-5001 through 31-8052168.     
PA-31P................................  31P-3 through 31P-7730012.      
PA-31T................................  31T-7400002 through 31T-8020076.
PA-31T1...............................  31T-7804001 through 31T-8004040.
------------------------------------------------------------------------

    Note 1: This AD applies to each airplane identified in the 
preceding applicability provision, regardless of whether it has been 
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 (g) 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 in the body of this AD, unless 
already accomplished.
    To prevent separation of a MLG door from the airplane caused by 
a cracked MLG inboard door hinge or attachment angle, which could 
result in the MLG becoming jammed with consequent loss of control of 
the airplane during landing operations, accomplish the following:
    (a) Within the next 100 hours time-in-service (TIS) after the 
effective date of this AD, unless already accomplished (compliance with 
AD 80-26-05), and thereafter at intervals not to exceed 100 hours TIS 
until the modification required by paragraph (c) or (d) of this

[[Page 54598]]

AD is incorporated, inspect (using dye penetrant methods) the MLG 
inboard door hinges and attachment angles for cracks. Accomplish the 
inspections in accordance with the INSTRUCTIONS section of Piper 
Service Bulletin No. 682, dated July 24, 1980.
    (b) The initial dye penetrant inspection type must be utilized 
for all future repetitive inspections. Dye penetrant inspection 
types consist of Type I: fluorescent; Type II: non-fluorescent or 
visible dye; and Type III: dual sensitivity.
    (c) If cracks are found during any of the inspections required 
in paragraph (a) of this AD, prior to further flight, install a 
Piper P/N 47529-32 MLG inboard door hinge and attachment angle 
assembly or install FAA-approved MLG inboard door hinges and angles 
made of steel.
    (d) Within the next 800 hours TIS after the effective date of 
this AD, unless already accomplished as required by paragraph (c) of 
this AD, install a Piper P/N 47529-32 MLG inboard door hinge and 
attachment angle assembly in all four hinge assembly locations or 
install FAA-approved MLG inboard door hinges and angles made of 
steel in all four hinge assembly locations.
    (e) Installing a Piper P/N 47529-32 MLG inboard door hinge and 
attachment angle assembly in all four assembly locations or 
installing FAA-approved MLG inboard door hinges and angles made of 
steel in all four assembly locations as required by paragraphs (c) 
and (d) of this AD is considered terminating action for the 
repetitive inspection requirement of this AD.
    (f) 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.
    (g) 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), One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, 
Georgia 30349.
    (1) The request shall be forwarded through an appropriate FAA 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Atlanta ACO.
    (2) Alternative methods of compliance approved in accordance 
with AD 80-26-05 (superseded by this action) are not considered 
approved as alternative methods of compliance with this AD.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.

    (h) All persons affected by this directive may obtain copies of 
the document referred to herein upon request to The New Piper 
Aircraft, Inc., 2926 Piper Drive,Vero Beach, Florida 32960; or may 
examine this document at the FAA, Central Region, Office of the 
Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri 64106.
    (i) This amendment supersedes AD 80-26-05, mendment 39-3994.

    Issued in Kansas City, Missouri, on October 14, 1997.
Mary Ellen Schutt,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 97-27794 Filed 10-20-97; 8:45 am]
BILLING CODE 4910-13-U