AIRWORTHINESS DIRECTIVE

CAA-AD-008/2002

Supersedes CAA-AD-107/2001

Date of issue: January 10, 2002

AIRCRAFT - MAIN LANDING GEAR - SWINGING LEVER SPACER (ATA 32) - REPLACEMENT

Applicability: The present AD applies to main landing gears installed on ATR 42-200, -300, -320, -400, and -500 series aircraft models on which ATR modification 5338 (Service Bulletin ATR 42-32-0094) has not been embodied.

Effective date: February 21, 2002

Compliance: Required as indicated in DGAC AD 2001-614-089(B).

Remarks: The compliance of this AD must be recorded in Aircraft Logbook, where applicable the requirements of this AD must be integrated into Aircraft Technical Documentation. Address inquiries concerning this AD to: Civil Aviation Authority, Airworthiness Division, Ruzyne Airport, 160 08 Prague 6, Czech Republic, tel.: 420 2 33320922, fax: 420 2 20562270.

Ing. Pavel MATOUŠEK

Director of Airworthiness Division

CAA CZ

DGAC AD No.: 2001-614-089(B)

ATR

ATR 42 aircraft

Main Landing Gear - Swinging lever spacer (ATA 32)

1. APPLICABILITY:

The present AD applies to main landing gears installed on ATR 42-200, -300, -320, -400, and -500 series aircraft models on which ATR modification 5338 (Service Bulletin ATR 42-32-0094) has not been embodied.

2. REASONS:

Several cases of fatigue cracks have been evidenced on MLG swinging lever spacer. These fatigue cracks, localised at the intersection base of the spacer, are due to a stress concentration induced by a transfer of some loads, by friction, from the swinging lever to the spacer through the swinging lever/barrel hinge pin.

The propagation of one of theses cracks could result in the failure of the spacer base and potentially affect, during some operating phases, the symmetrical functioning of the braking system. This asymmetrical braking could result, in case of strong crosswind at landing, in reduced aircraft controllability.

The results of the investigations and of the metallurgical analysis have showed that the crack length remains limited; in addition no case of spacer fatigue failure has ever been reported.

This subject was addressed by Airworthiness Directive (AD) 2001-550-086(B).

This AD takes over the requirements of AD 2001-550-086(B) and modifies the compliance time.

3. ACTIONS:

In order to prevent a ta6gue failure of the MLG swinging lever spacer, the following measures are rendered mandatory on the effective date of this AD:

For ATR 42-200, -300 and -320:

Before reaching 15,000 landings since new or since last overhaul of the MLG, or before reaching 3,000 landings following the effective date of this AD, whichever occurs later, replace the MLG swinging lever spacer by a modified spacer in accordance with Service Bulletin ATR 42-32-0094.

In any case, perform this replacement before reaching 8 years since new or since last overhaul of the MLG.

For ATR 42-400 and -500:

Before reaching 9 years or 18,000 landings since new or since last overhaul of the MLG, whichever occurs first, replace the MLG swinging lever spacer by a modified spacer in accordance with Service Bulletin ATR 42-32-0094.

Note: It is recommended to embody SB ATR 42-32-0094 at the next MLG overhaul.

REF.: Service Bulletin ATR 42-32-0094

Any later approved revision of this SB is acceptable.

This AD replaces AD 2001-550-086(B) which is cancelled.

EFFECTIVE DATE: JANUARY 01, 2002