AD 98-24-14

98-24-14 CESSNA AIRCRAFT COMPANY: Priority Letter issued on November 13, 1998. Docket No. 98-CE-111-AD.

Applicability: The following airplane models and serial numbers, certificated in any category, that are equipped with any WYE tube, P/N 9910299-25 or P/N 9910299-26, in the engine exhaust system:

Model
Serial Numbers
340A
215 through 1817
414A
1 through 1212

NOTE 1: This AD allows the aircraft owner or pilot to check the maintenance records to determine whether any WYE tube, P/N 9910299-25 or P/N 9910299-26, has been installed in the engine exhaust system since May 1998. See paragraph (c) of this AD for authorization.

NOTE 2: Cessna is considering issuing service information pertaining to this subject. This AD takes precedence over any existing or future service information on this subject.

NOTE 3: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repairedin 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 (d) 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 detect and correct exhaust leaks caused by nonwelded exhaust system components, which could result in aluminum fuel lines bursting with consequent fuel spillage, an airplane fire, and/or an explosion, accomplish the following:

(a) Prior to further flight after receipt of this priority letter AD, remove from service any P/N 9910299-25 or P/N 9910299-26 engine exhaust system WYE tube. These P/N 9910299-25 or P/N 9910299-26 WYE tubes may be replaced with any of the following in accordance with the instructions in the applicable maintenance manual or other applicable FAA-approved document:

(1) P/N 9910299-8 (for the P/N 9910299-25) or P/N 9910299-9 (for the P/N 9910299-26) WYE tubes; or

(2) Any other FAA-approved engine exhaust system WYE tube that is not P/N 9910299-25 or P/N 9910299-26.

(b) As of the receipt of this priority letter AD, no person shall install, on any affected airplane, any P/N 9910299-25 or P/N 9910299-26 engine exhaust system WYE tube.

(c) The owner/operator holding at least a private pilot certificate as authorized by section 43.7 of the Federal Aviation Regulations (14 CFR 43.7) may check the maintenance records to determine whether any WYE tube,
P/N 9910299-25 or P/N 9910299-26, has been installed in the engine exhaust system since May 1998. If one of these WYEtubes is not installed, the AD does not apply and the owner/operator must make an entry into the aircraft records showing compliance with this AD in accordance with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9).

(d) An alternative method of compliance or adjustment of the compliance times that provides an equivalent level of safety may be approved by the Manager, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Rm. 100, Mid-Continent Airport, Wichita, Kansas, 67209. The request shall be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Wichita ACO.

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from Wichita ACO.

(e) Information related to this priority letter AD may be examined at the FAA, Central Region, Office of the Regional Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106.(f) Priority letter AD 98-24-14, issued November 13, 1998, becomes effective immediately upon receipt.

DATE: November 13, 1998
98-24-14

Actions Leading to This Priority Letter Airworthiness Directive (AD)
The FAA has received reports of five instances where the engine exhaust components in the WYE tube installed on certain Cessna Models 340A and 414A airplanes were manufactured without welds on critical parts that are installed adjacent to the firewall. These nonwelded areas lead to leaks in the exhaust system on the turbocharged engine installations of these airplanes. The heat from leaks in the exhaust system have caused aluminum fuel lines located immediately behind the firewall to burst.

This condition is due to a quality control problem and Cessna has reported the problem and returned the existing inventory to its supplier. A total of approximately 25 WYE tubes were distributed to the field beginning in May 1998. A check of the maintenance records would show whether one or more of these WYE tubes has been installed on one of the affected airplanes since May 1998.This condition, if not detected and corrected in a timely manner, could result in these fuel lines bursting due to exhaust system leaks with consequent fuel spillage, an airplane fire, and/or an explosion.

The FAA s Determination
After examining the circumstances and reviewing all available information related to the incidents described above, the FAA has determined that:

1. Any WYE tube, part number (P/N) 9910299-25 or P/N 9910299-26, in the engine exhaust system should be removed from service; and

2. Priority letter AD action should be taken to detect and correct exhaust leaks caused by nonwelded exhaust system components, which could result in aluminum fuel lines bursting with consequent fuel spillage, an airplane fire, and/or an explosion.

Provisions of This Priority Letter AD
Since an unsafe condition has been identified that is likely to exist or develop in other Cessna Models 340A and 414A airplanes of the same type design that are equipped with any WYE tube, P/N 9910299-25 or P/N 9910299-26, in the engine exhaust system, the FAA is taking priority letter AD action. This priority letter requires removing from service any P/N 9910299-25 or P/N 9910299-26 engine exhaust system WYE tube.

These P/N 9910299-25 or P/N 9910299-26 WYE tubes may be replaced with any of the following:

- P/N 9910299-8 (for the P/N 9910299-25) or P/N 9910299-9 (for the P/N 9910299-26) WYE tubes; or

- Any other FAA-approved engine exhaust system WYE tube that is not P/N 9910299-25 or P/N 9910299-26.

The owner/operator holding at least a private pilot certificate as authorized by section 43.7 of the Federal Aviation Regulations (14 CFR 43.7) may check the maintenance records to determine whether any WYE tube, P/N 9910299-25 or P/N 9910299-26, has been installed in the engine exhaust system since May 1998. If one of these WYE tubes is not installed, the AD does not apply and the owner/operator must make an entry into the aircraft records showing compliance with this AD in accordance with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9).

Presentation of the Actual AD
This rule is issued under 49 U.S.C. Section 44701 (formerly section 601 of the Federal Aviation Act of 1958), pursuant to the authority delegated to me by the Administrator, and is effective immediately upon receipt of this priority letter.