News Archive

PRIORITY LETTER AIRWORTHINESS DIRECTIVE REGULATORY SUPPORT DIVISION P.O. BOX 26460 OKLAHOMA CITY, OKLAHOMA 73125-0460

U.S. Department of Transportation Federal Aviation Administration

DATE: May 28, 1999
99-12-02

Actions Leading to This Priority Letter Airworthiness Directive (AD)

The FAA has received a report of an in-flight separation of the right wing on a Raytheon Beech Model A45 (T-34A) airplane. The airplane was involved in mock aerial combat with another Beech Model A45 (T-34A) airplane.

The left wing remained attached to the airplane following separation of the right wing. As the airplane made ground contact, the left wing forward and rear spars and wing attach fittings sustained overload fractures.

Examination of the right wing revealed structural fatigue cracks at several of the fracture surfaces. Although it did not separate from the airplane, the left wing also showed structural fatigue cracks at several locations.

The Raytheon Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes were designed as military trainers over 40 years ago. Today, these airplanes are used in mock aerial combat operations, air show routines, and aerobatic maneuvers.

Service Information

Raytheon has issued Safety Communique No. 162, Rev. 1, dated June 1999, which presents information related to the accident described above and recommends not operating the Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes.

Raytheon is in the process of developing inspection procedures for the wings of the affected airplanes. However, because of the complex structure of the wing, no timetable for completion of this project can be estimated at this time.

The FAA’s Determination

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

- the Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes should not be operated without restrictions until the wing structure has been inspected in accordance with inspection procedures approved by the FAA, and the structure is found to be free of cracks;

- all of the above-referenced airplanes should be restricted to normal category operation and prohibited from acrobatic and utility category operations; the flight load factor should be limited to 0 to 2.5 G; and the maximum airspeed should be limited to 175 miles per hour (mph) (152 knots); and

- AD action should be taken to assure the operational safety of these airplanes.

Provisions of This Priority Letter AD

Since an unsafe condition has been identified that is likely to exist or develop on other Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes of the same type design, the FAA is taking priority letter AD action. This AD requires fabricating two placards using letters of at least 1/10-inch in height with each consisting of the following words, and installing these placards on the airplane instrument panels (one on the front panel and one on the rear panel) next to the airspeed indicators within the pilot’s clear view:

"Never exceed speed, Vne-175 MPH (152 knots) IAS; Normal Acceleration (G) Limits – 0, and +2.5; ACROBATIC MANEUVERS PROHIBITED."

This AD also requires marking the airspeed indicators to specify the limitations referenced in the placards, and incorporating a copy of the AD into the Limitations Section of the Airplane Flight Manual (AFM).

The actions required by this AD are different than those recommended in Raytheon Safety Communiqu? No. 162, Rev. 1, dated June 1999, which specifies not operating the affected airplanes. Based on the service history of the wing structure of the Raytheon Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes and all available information related to the referenced accident, the FAA has determined that the restrictions imposed by this AD will continue to assure the operational safety of these airplanes until detailed inspection procedures are developed.

When inspection procedures are developed for the wing structure of the affected airplanes, the FAA will evaluate these procedures and will decide whether to initiate further rulemaking action. Further action may include alleviating the restrictions imposed by this AD.

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.

99-12-02 RAYTHEON AIRCRAFT COMPANY: Priority Letter issued on May 28, 1999; Docket No. 99-CE-22-AD.

Applicability: Beech Models 45 (YT-34), A45 (T-34A, B-45), and D45 (T-34B) airplanes, all serial numbers, 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 (e) 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 assure the operational safety of the above-referenced airplanes, accomplish the following:

(a) Prior to further flight after receipt of this priority letter AD, accomplish the following:

(1) Fabricate two placards using letters of at least 1/10-inch in height with each consisting of the following words:

"Never exceed speed, Vne-175 MPH (152 knots) IAS; Normal Acceleration (G) Limits – 0, and +2.5; ACROBATIC MANEUVERS PROHIBITED."

(2) Install these placards on the airplane instrument panels (one on the front panel and one on the rear panel) next to the airspeed indicators within the pilot’s clear view.

(3) Insert a copy of this AD into the Limitations Section of the Airplane Flight Manual (AFM).

(b) Within the next 10 hours time-in-service (TIS) after receipt of this priority letter AD, modify the airspeed indicator glass by accomplishing the following:

(1) Place a red radial line on the indicator glass at 175 miles per hour (mph) (152 knots).

(2) Place a white slippage index mark between the airspeed indicator glass and the case to visually verify that the glass has not rotated.

(c) Within the next 10 hours TIS after receipt of this priority letter, mark the outside surface of the "g" meters with lines of approximately 1/16-inch by 3/16-inch, as follows:

(1) A red line at 0 and 2.5; and

(2) A white slippage mark between each "g" meter glass and case to visually verify that the glass has not rotated.

(d) Fabricating and installing the placards and inserting a copy of this AD into the AFM as required by paragraphs?(a)(1), (a)(2), and (a)(3) of this AD, respectively, may be performed by 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), and must be entered into the aircraft records showing compliance with this AD in accordance with section 43.9 of the Federal Aviation Regulations (14 CFR 43.9).

(e) 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 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from Wichita ACO.

(f) 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.

(g) Priority letter AD 99-12-02, issued May 28, 1999, becomes effective immediately upon receipt.

FOR FURTHER INFORMATION CONTACT: