AD 97-04-13

This amendment adopts a new airworthiness directive (AD) that applies to Mitsubishi Heavy Industries, Ltd., (Mitsubishi) MU-2B series airplanes. This AD requires removing the vent check valve assembly from the bulkhead between the fuel tanks. This AD results from an incident where both engines on an affected airplane failed near the end of a flight because of lack of fuel to the engines. The incident is attributed to the fuel filler caps on the top of the wings not sealing correctly. The actions specified by this AD are intended to prevent the inability of both engines to utilize the entire fuel supply because of the outboard fuel not transferring to the center tank, which could result in an uncommanded engine shutdown.

Final rule.

97-04-13 MITSUBISHI HEAVY INDUSTRIES, LTD.: Amendment 39-9938; Docket No. 96-CE-45-AD.

Applicability: Models MU-2B, MU-2B-10, MU-2B-15, MU-2B-20, and MU-2B-30 airplanes (serial numbers 004 through 035, 037, 038, 101 through 230, 502 through 525, and 527 through 547), certificated in any category.

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 (c) 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 within the next 60 calendar days after the effective date of this AD, unless already accomplished.

To prevent the inability of both engines to utilize the entire fuel supply because of the outboard fuel not transferring to the center tank, which could result in an uncommanded engine shutdown, accomplish the following:

(a) Remove the vent check valve assembly in accordance with the instructions in Mitsubishi MU-2 Service Bulletin No. 130A, dated July 19, 1971.

(b) 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.

(c) An alternative method of compliance or adjustment of the compliance time that provides an equivalent level of safety may be approved by the Manager, FAA, Los Angeles Aircraft Certification Office(ACO), 3960 Paramount Boulevard., Lakewood, California 90712. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Los Angeles ACO.

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

(d) The removal required by this AD shall be done in accordance with Mitsubishi MU-2 Service Bulletin No. 130A, dated July 19, 1971. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Mitsubishi Heavy Industries, Ltd., Nagoya Aerospace Systems, 10, Oyecho, Minato-Ku, Nagoya, Japan. Copies may be inspected at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri, or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on April 16, 1997.

Events Leading to the Issuance of This AD
A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an AD that would apply to Mitsubishi MU-2B series airplanes was published in the Federal Register as a notice of proposed rulemaking (NPRM) on October 30, 1996 (61 FR 53939). The NPRM proposed to require removing the vent check valve assembly from the bulkhead between the fuel tanks. Accomplishment of the proposed action as specified in the NPRM would be in accordance with Mitsubishi MU-2 Service Bulletin No. 130A, dated July 19, 1971.

The NPRM is the result of an incident where both engines on an affected airplane failed near the end of a flight because of lack of fuel to the engines. The incident is attributed to the fuel filler caps on the top of the wings not sealing correctly.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were receivedon the proposed rule or the FAA's determination of the cost to the public.

The FAA's Determination
After careful review of all available information related to the subject presented above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed except for minor editorial corrections. The FAA has determined that these minor corrections will not change the meaning of the AD and will not add any additional burden upon the public than was already proposed.

Compliance Time of This AD
The compliance time for this AD is presented in calendar time instead of hours time-in-service. The fuel filler cap may not seal properly regardless of whether the airplane is in operation. For this reason, the FAA has determined that a calendar time for compliance is the most desirable.

Cost Impact
The FAA estimates that 14 airplanes in the U.S. registry will be affected by this AD, that it will take approximately 3 workhours (average:4 workhours for seven airplanes and 2 workhours for seven airplanes) per airplane to accomplish the required action, and that the average labor rate is approximately $60 an hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $2,520.

The above figure is based on the presumption that no owner/operator of the affected airplanes has accomplished the required vent check valve assembly removal. The FAA is aware that seven of the affected airplanes are already in compliance with this AD. With this information in mind, the cost impact upon U.S. operators/owners is reduced by $1,260 from $2,520 to $1,260.

Regulatory Impact
The regulations adopted herein will 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 final rule does 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) 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 final evaluation prepared for this action is contained 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, Incorporation by reference, Safety.

Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive (AD) to read as follows: