[Federal Register Volume 61, Number 13 (Friday, January 19, 1996)]
[Proposed Rules]
[Pages 1303-1306]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-485]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 90-CE-61-AD]


Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly 
Piper Aircraft Corporation) Models PA31T, PA31T1, PA31T2, and PA31T3 
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) 84-08-06, which currently requires the following on certain The 
New Piper Aircraft, Inc. (Piper) Models PA31T, PA31T1, PA31T2, and 
PA31T3 airplanes: repetitively inspecting the fuselage station (FS) 332 
bulkhead for cracks, and reinforcing or replacing the FS 332 bulkhead 
if cracks are found. The Federal Aviation Administration's policy on 
aging commuter-class aircraft is to eliminate or, in certain instances, 
reduce the number of certain repetitive short-interval inspections when 
improved parts or modifications are available. The proposed action 
would retain the current repetitive inspections contained in AD 84-08-
06, and would require incorporating a stabilizer forward spar 
attachment bulkhead reinforcement kit or installing a reinforced 
bulkhead assembly as terminating action for the repetitive inspection 
requirement. The actions specified in the proposed AD are intended to 
prevent structural failure of the horizontal stabilizer and the aft 
fuselage attachment caused by cracks in the FS 332 bulkhead, which, if 
not detected and corrected, could result in loss of control of the 
airplane.

DATES: Comments must be received on or before March 23, 1996.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Central Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 90-CE-61-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, Campus Building, 1701 
Columbia Avenue, suite 2-160, College Park, Georgia 30337-2748; 
telephone (404) 305-7362; facsimile (404) 305-7348.

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. 90-CE-61-AD.'' The postcard will be date stamped and 
returned to the commenter. 

[[Page 1304]]


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. 90-CE-61-AD, Room 1558, 601 E. 12th Street, 
Kansas City, Missouri 64106.

Discussion

    The FAA has determined 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 if the known problem is not detected during the 
inspection; (2) the probability of the problem not being detected 
during the inspection; (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.
    These factors have led the FAA to establish an aging commuter-class 
aircraft policy that requires incorporating a known design change when 
it could replace a critical repetitive inspection. With this policy in 
mind, the FAA conducted a review of existing AD's that apply to Piper 
Models PA31-350 and PA31T3 airplanes. Assisting the FAA in this review 
were (1) The New Piper Aircraft, Inc.; (2) the Regional Airlines 
Association (RAA); and (3) several operators of the affected airplanes.
    From this review, the FAA has identified AD 84-08-06, Amendment 39-
4851, as one that should be superseded with a new AD that would require 
a modification that would eliminate the need for short-interval and 
critical repetitive inspections. AD 84-08-06 currently requires the 
following on Piper Models PA31T, PA31T1, PA31T2, and PA31T3 airplanes:

--Repetitively inspecting the fuselage station (FS) 332 bulkhead for 
cracks, reinforcing the FS 332 bulkhead (Piper Kit 764-983) if all 
cracks found do not exceed certain limits, and replacing the bulkhead 
assembly with a reinforced replacement bulkhead assembly (part number 
45583-16 or 45583-17) if any crack is found that exceeds certain 
limits. Accomplishment of the inspections required by AD 84-08-06 is in 
accordance with Piper Service Bulletin (SB) No. 773, dated December 19, 
1983; and
--Allowing for the provision of incorporating Piper Kit 764-983 or part 
number 45583-16 or 45583-17 bulkhead assembly as terminating action for 
the repetitive inspection requirement. The incorporation of Piper Kit 
764-983 is accomplished in accordance with the instructions provided 
with the kit, and the reinforced bulkhead assembly installations are 
accomplished in accordance with the applicable maintenance manual.

    Based on its aging commuter-class aircraft policy and 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 eliminate the repetitive short-interval 
inspections required by AD 84-08-06, and to prevent structural failure 
of the horizontal stabilizer and the aft fuselage attachment caused by 
cracks in the FS 332 bulkhead, which, if not detected and corrected, 
could result in loss of control of the airplane.
    Since an unsafe condition has been identified that is likely to 
exist or develop in other Piper Models PA31T, PA31T1, PA31T2, and 
PA31T3 airplanes of the same type design, the proposed AD would 
supersede AD 84-08-06 with a new AD that would (1) retain the 
requirement of repetitively inspecting the FS 332 bulkhead for cracks, 
reinforcing the FS 332 bulkhead (Piper Kit 764-983) if any crack is 
found that does not exceed certain limits, and replacing the bulkhead 
assembly with a reinforced bulkhead assembly (part number 45583-16 or 
45583-17) if any crack is found that exceeds certain limits; and (2) 
require incorporating a stabilizer forward spar attachment bulkhead 
reinforcement (Piper Kit 764-983) or a reinforced bulkhead assembly 
(part number 45583-16 or 45583-17) as terminating action for the 
repetitive inspections. Accomplishment of the proposed inspections 
would be in accordance with Piper SB No. 773A, dated May 3, 1984. The 
incorporation of Piper Kit 764-983 would be accomplished in accordance 
with the instructions to this kit (Revised June 18, 1990), and the 
reinforced bulkhead installations would be accomplished in accordance 
with the applicable maintenance manual.
    The FAA estimates that 736 airplanes in the U.S. registry would be 
affected by the proposed AD, that it would take approximately 60 
workhours per airplane to accomplish the proposed replacement, and that 
the average labor rate is approximately $60 an hour. Parts cost 
approximately $782 per airplane. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be 
$3,225,152 or $4,382 per airplane. This figure is based on the 
assumption that no affected airplane owner/operator has accomplished 
the proposed replacement.
    Piper has informed the FAA that parts have been distributed to 
enough owners/operators to equip 348 of the affected airplanes. 
Assuming that each set of parts has been installed on an affected 
airplane, the cost impact of the proposed AD upon U.S. owners operators 
of the affected airplanes would be reduced by $1,524,936 from 
$3,225,152 to $1,700,216.
    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 388 affected 
airplanes (736 affected airplanes--348 sets of parts distributed) that 
would be affected by the proposed modification AD are operated in 
various types of air transportation. This includes scheduled passenger 
service, air cargo, and air taxi.
    The proposed AD allows 600 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 four to six 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 three to six years before 
the proposed modification would be mandatory.
    The FAA established the 600 hours TIS replacement compliance time 
based on its engineering evaluation of the problem. Among the issues 
looked at 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 

[[Page 1305]]
``within the next 600 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 PA31T, PA31T1, 
PA31T2, and PA31T3 airplanes (such as 5,000 hours TIS) would impose the 
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 six years to allow low-usage 
airplanes time to accumulate the 600 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 
while still minimizing the impact on the private airplane owners of 
Piper Models PA31T, PA31T1, PA31T2, and PA31T3 airplanes.
    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 USC 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Airworthiness Directive 
(AD) 84-08-06, Amendment 39-4851, and by adding a new AD to read as 
follows:

The New Piper Aircraft, Inc. (formerly Piper Aircraft Corporation): 
Docket No. 90-CE-61-AD. Supersedes AD 84-08-06, Amendment 39-4851.

    Applicability: The following model and serial number airplanes, 
certificated in any category, that do not have either Piper Kit 764-
983 (stabilizer forward spar attachment bulkhead reinforcement) 
incorporated at Fuselage Station (FS) 332 or have a part number (P/
N) 45583-16 or P/N 45583-17 bulkhead assembly installed:

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              Models                             Serial No.             
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PA31T............................  31T-7400002 through 31T-8120104.     
PA31T1...........................  31T-7804001 through 31T-8104101, 31T-
                                    8304003, and 31T-1104004 through 31T-
                                    1104007.                            
PA31T2...........................  31T-8166001 through 31T-8166032, 31T-
                                    8166034 through 31T-8166065, 31T-   
                                    8166067 through 31T-8166071, and 31T-
                                    8166073 through 31T-8166075.        
PA31T3...........................  31T-8275001, 31T-8275003 through 31T-
                                    8275012, 31T-8275014 through 31T-   
                                    8275017, 31T-8275025, and 31T-      
                                    8375001 through 31T-8375005.        
------------------------------------------------------------------------

    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 (h) 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 structural failure of the horizontal stabilizer and 
the aft fuselage attachment caused by cracks in the FS 332 bulkhead, 
which, if not detected and corrected, could result in loss of 
control of the airplane, accomplish the following:
    (a) Within the next 200 hours time-in-service (TIS) after the 
effective date of this AD, unless already accomplished (compliance 
with AD 84-08-06), and thereafter at intervals not to exceed 200 
hours TIS until the modification required by paragraph (c), (d), or 
(e) of this AD is incorporated, inspect (using dye penetrant 
methods) the FS 332 bulkhead for cracks. Accomplish the inspections 
in accordance with the INSTRUCTIONS section of Piper Service 
Bulletin No. 773A, dated May 3, 1984.
    (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 and no crack exceeds the limitations 
specified in Piper SB No. 773A, dated May 3, 1984, prior to further 
flight, repair the cracks in accordance with Piper SB No. 773A, 
dated May 3, 1984, and reinforce the FS 332 bulkhead by 
incorporating Piper Kit 764-983 in accordance with the instructions 
to Piper Kit 764-983, Revised June 18, 1990.
    (d) If cracks are found during any of the inspections required 
in paragraph (a) of this AD and any crack exceeds the limitations 
specified in Piper SB No. 773A, dated May 3, 1984, prior to further 
flight, replace the bulkhead assembly with a reinforced bulkhead 
assembly, P/N 45583-16 or P/N 45583-17. Accomplish this replacement 
in accordance with the applicable maintenance manual.
    (e) Upon the accomplishment of the third repetitive inspection 
required by this AD (600 hours TIS after the effective date of this 
AD), unless already accomplished as required by paragraph (c) or (d) 
of this AD, accomplish one of the following, as applicable:
    (1) If cracks are found and no crack exceeds the limitations 
specified in Piper SB No. 773A, dated May 3, 1984, repair the cracks 
in accordance with Piper SB No. 773A, dated May 3, 1984, and 
reinforce the FS 332 bulkhead by incorporating Piper Kit 764-983 in 
accordance with the instructions to Piper Kit 764-983, Revised June 
18, 1990;
    (2) If cracks are found and any crack exceeds the limitations 
specified in Piper SB No. 773A, dated May 3, 1984, replace the 
bulkhead assembly with a reinforced bulkhead assembly, P/N 45583-16 
or P/N 45583-17, in accordance with the applicable maintenance 
manual; or
    (3) If no cracks are found, either reinforce the FS 332 bulkhead 
by incorporating Piper Kit 764-983 in accordance with the 
instructions to Piper Kit 764-983, Revised June 18, 1990; or replace 
the bulkhead assembly with a reinforced bulkhead assembly, P/N 
45583-16 or P/N 45583-17, in accordance with the applicable 
maintenance manual.
    (f) Incorporating Piper Kit 764-983 or installing reinforced 
bulkhead assembly, P/N 45583-16 or P/N 45583- 17, as required by 
paragraphs (c) and (d) or (e) of this AD is considered terminating 
action for the repetitive inspection requirement of this AD. 

[[Page 1306]]

    (g) 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.
    (h) 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), Campus Building, 1701 Columbia Avenue, suite 2-160, College 
Park, Georgia 30337-2748. 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 2: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Atlanta ACO.
    Note 3: Alternative methods of compliance approved in accordance 
with AD 84-08-06 (superseded by this action) are not considered 
approved as alternative methods of compliance with this AD.

    (i) 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 
Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, 
Missouri 64106.
    (j) This amendment supersedes AD 84-08-06, Amendment 39-4851.

    Issued in Kansas City, Missouri, on January 10, 1996.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 96-485 Filed 1-18-96; 8:45 am]
BILLING CODE 4910-13-U