Airworthiness Directives; The New Piper Aircraft, Inc. (Formerly Piper Aircraft Corporation) PA-31 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); Reopening of the comment period.

SUMMARY:

This document proposes to revise an earlier proposed airworthiness directive (AD) that would apply to The New Piper Aircraft, Inc. (Piper) PA-31 series airplanes. The earlier NPRM would have superseded AD 80-26-05, which requires you to repetitively inspect the main landing gear (MLG) inboard door hinges and attachment angles for cracks on the affected airplanes, and requires you to replace any cracked MLG inboard door hinge or attachment angle. The earlier NPRM proposed to require you to inspect the original design MLG inboard door hinge assemblies for cracks; and replace the original design MLG inboard door hinge assemblies with parts of improved design either immediately (cracks) or at a certain time period (no cracks). This supplemental NPRM results from reports of cracks in the improved design MLG inboard door hinge assemblies on the affected airplanes. We are revising the NPRM to propose inspections on the improved design parts as well as the original design parts. The actions specified by the proposed AD are intended to detect and correct cracked MLG inboard door hinge assemblies. These cracked door hinge assemblies could result in the MLG becoming jammed with consequent loss of control of the airplane during landing operations.

DATES:

The Federal Aviation Administration (FAA) must receive comments on or before September 8, 2000.

ADDRESSES:

Submit comments in triplicate to FAA, Central Region, Office of the Regional Counsel, Attention: Rules Docket No. 96-CE-69-AD, 901 Locust, Room 506, Kansas City, Missouri 64106.

You may get the service information referenced in the proposed AD from The New Piper Aircraft, Inc., Customer Services, 2926 Piper Drive, Vero Beach, Florida 32960. You may examine this information at FAA.

FOR FURTHER INFORMATION CONTACT:

William O. Herderich, Aerospace Engineer, FAA, Atlanta Aircraft Certification Office, One Crown Center, 1895 Phoenix Boulevard, suite 450, Atlanta, Georgia 30349; telephone: (770) 703-6084; facsimile: (770) 703-6097; e-mail: william.o.herderich@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

How do I comment on the proposed AD? The FAA invites comments on this proposed rule. You may submit whatever written data, views, or arguments you choose. You need to include the rule's docket number and submit your comments in triplicate to the address specified under the caption ADDRESSES. The FAA will consider all comments received on or before the closing date. We may amend the proposed rule in light of comments received. Factual information that supports your ideas and suggestions is extremely helpful in evaluating the effectiveness of the proposed AD action and determining whether we need to take additional rulemaking action.

Are there any specific portions of the AD I should pay attention to? The FAA is re-examining the writing style we currently use in regulatory documents, in response to the Presidential memorandum of June 1, 1998. That memorandum requires federal agencies to communicate more clearly with the public. We are interested in your comments on whether the style of this document is clearer, and any other suggestions you might have to improve the clarity of FAA communications that affect you. You can get more information about the Presidential memorandum and the plain language initiative at http://www.plainlanguage.gov.

The FAA specifically invites comments on the overall regulatory, economic, environmental, and energy aspects of the proposed rule that might suggest a need to modify the rule. You may examine all comments we receive before and after the closing date of the rule in the Rules Docket. We will file a report in the Rules Docket that summarizes each FAA contact with the public that concerns the substantive parts of the proposed AD.

How can I be sure FAA receives my comment? If you want us to acknowledge the receipt of your comments, you must include a self-addressed, stamped postcard. On the postcard, write “Comments to Docket No. 96-CE-69-AD.” We will date stamp and mail the postcard back to you.

Discussion

Has FAA taken any action to this point? On December 1, 1995, 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 certain Piper PA-31 series 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:

—Retain the requirement of repetitively inspecting the MLG inboard door hinge assemblies for cracks, and replacing any cracked MLG inboard door hinge assembly; and

—Require incorporating a MLG inboard door hinge assembly of improved design (part number (P/N) 47529-32) or FAA-approved equivalent part number, as terminating action for the repetitive inspection requirement.

Accomplishment of the proposed inspections would have been required in accordance with Piper Service Bulletin (SB) No. 682, dated July 24, 1980.

Was the public invited to comment on the NPRM? The FAA invited interested persons to participate in the making of this amendment. Due consideration was given to the one comment received.

What issue did this comment address? The comment received on the NPRM contained information that the improved design MLG inboard door hinge assemblies, 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 stated that its airplane fleet has experienced three failures and three incidents related to fatigue cracking of the P/N 47529-32 hinge assemblies.

What action did FAA take? We conducted a review of the manufacturer's service history and service difficulty reports in FAA's 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, we determined that more information and analysis were needed before mandating MLG inboard door hinge assembly replacements through an AD.

We then issued an advance notice of proposed rulemaking (ANPRM) on February 11, 1997. The ANPRM was published in the Federal Register on February 19, 1997 (62 FR 7375). The purpose of the ANPRM was to encourage interested persons to provide information that describes what they consider the best action (if any) for FAA to take regarding the P/N 47529-32 MLG inboard door hinge assembly issue. The FAA also withdrew the NPRM. We received no information or comments regarding the ANPRM.

We then re-evaluated the information in our service difficulty database. The database, at that time, contained 10 reports of failure or cracks found in the MLG inboard door hinge assembly on the affected airplanes. The commenter to the original NPRM had submitted six of these reports. Three of these six incident reports were specifically attributed to the original MLG inboard door hinge assemblies and three to the improved design MLG inboard door hinge assemblies. The four reports that others submitted do not specifically identify whether the original MLG inboard door hinge assemblies were installed or the improved design assemblies were installed. Since 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, we presumed that the original hinge assemblies were installed.

The FAA then reviewed the three incident reports on the improved design MLG inboard door hinge assemblies and, along with the National Transportation Safety Board (NTSB), performed extensive testing and analysis of the improved design MLG inboard door hinge assemblies. Based on this review, testing, and analysis, we determined that:

—The incidents were isolated and that mandating repetitive inspections was not needed when the P/N 47529-32 MLG inboard door hinge assemblies are installed; and

—AD action should be taken to eliminate the repetitive short-interval inspections that AD 80-26-05 requires and to prevent separation of a MLG door from the airplane caused by a cracked inboard door hinge assembly.

On October 14, 1997, FAA issued an NPRM to address these issues. The NPRM was published in the Federal Register on October 21, 1997 (62 FR 54595).

What has happened to justify this AD action? Since issuance of the NPRM, we have received additional reports of cracks in the MLG inboard door hinge assemblies. The reports reference incidents on both the original design assemblies and the improved design hinges. As of the issue date of this document, we have reports of the following:

—27 reports of cracked improved design MLG inboard door hinge assemblies; and

—41 reports of cracked original design MLG inboard door hinge assemblies.

The FAA's Determination

What has FAA decided? After careful review of all available information related to the subject presented above, we have determined that:

—Both the improved design and original design MLG inboard door hinge assemblies on the PA-31 series airplanes are susceptible to cracking; and

—AD action should be taken to detect and correct cracked MLG inboard door hinge assemblies.

The Supplemental NPRM

How will the changes to the NPRM impact the public? Proposing inspections on airplanes with the improved design MLG inboard door hinge assemblies as well as the original design assemblies presents actions that go beyond the scope of what was already proposed. Therefore, we are issuing a supplemental NPRM and reopening the comment period to allow the public additional time to comment on the proposed AD.

What are the provisions of the supplemental NPRM? The supplemental NPRM would apply to all PA-31 series airplanes and would require you to accomplish the following:

—Repetitively inspect the MLG inboard door hinge assemblies (regardless of part number); and

—Immediately replace any cracked MLG inboard door hinge assembly with a new MLG inboard door hinge assembly, Piper part number (P/N) 47529-32 (or FAA-approved equivalent part number).

What document should I use to accomplish these actions? Piper Service Bulletin No. 682, dated July 24, 1980, includes all the procedures necessary to accomplish the actions proposed in this supplemental NPRM.

Cost Impact

How many airplanes does the proposed AD impact? The FAA estimates that 2,344 airplanes in the U.S. registry would be affected by the proposed AD.

What would it cost me to accomplish each proposed inspection? We estimate that it would take approximately 2 workhours per airplane to accomplish each proposed inspection, at an average labor rate of $60 an hour. Based on these figures, FAA estimates the total cost impact of each proposed inspection on U.S. operators at $281,280, or $120 per airplane.

What would it cost me to replace a cracked assembly? We estimate 2 workhours to replace a cracked MLG inboard door hinge assembly. A replacement assembly costs approximately $270. We estimate a total cost of $390 to replace a cracked MLG inboard door hinge assembly.

Regulatory Impact

How does this AD impact various entities? The regulations proposed herein 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. Therefore, it is determined that this proposed rule would not have federalism implications under Executive Order 13132.

How does this AD involve a significant rule or regulatory action? The FAA has determined that the proposed 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 adopted, will not have a significant economic impact on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. We have placed a copy of the draft regulatory evaluation prepared for this action in the Rules Docket. You may obtain a copy of it at 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, under 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), 40113, 44701.