AIRWORTHINESS DIRECTIVE

CAA-AD-018/2001

Date of issue: February 20, 2001

AIRCRAFT - ELECTRICAL CIRCUIT (ATA 92, 24, 29) – MODIFICATION

Applicability: Model ATR 72-101/-201/-102/-202/-211 and –212 on which modification 3719 has not been embodied.

Effective date: Upon receipt

Compliance: Required as indicated in DGAC AD 2001-056-055(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 ref. No.: 2001-056-055(B)

EADS ATR

ATR 72 aircraft

Electrical circuit – Wiring conduit between frame 28 and 28 A (ATA 92, 24, 29)

1. APPLICABILITY:

Model ATR 72-101/-201/-102/-202/-211 and –212 on which modification 3719 has not been embodied.

2. REASONS:

The issuance of this Airworthiness Directive (AD) is prompted by a recent event where, during taxi out, an ATR 72-202 experienced an elevator pitch disconnect followed by a loss of the green system hydraulic pump and by a fire initiation.

Investigations revealed that the power supply cables of the green system hydraulic pump chafed on the right hand elevator control cable, between frames 28 and 28 A. This chafing led to a short-circuit which caused the elevator control cable to snap and the hydraulic pump power supply circuit breaker to trip. The heat generated started a small fire which extinguished itself.

It has been determined that the electrical short-circuit was caused by the installation of an oversized clamp (diameter 20 mm) on the power supply cables loom (diameter 16 mm) of the green system hydraulic pump, which gave the cables freedom to move.

Under such conditions, this clamp doesn´t allow to correctly secure wiring conduit 2P in the forward area where the cable loom changes direction.

The following corrective actions mandated by this AD are intended to warrant a securely retain of the loom 2P containing the green system hydraulic pump power supply wiring.

3. ACTION:

The following measures are rendered mandatory on the effective date of this AD and have to be accomplished at the first opportunity, and at the latest before March 02, 2001.

At frame 28, remove the oversized clamp retaining the green circuit hydraulic pump power supply cable loom 2P and install, instead of, a clamp diameter 16 mm in respecting its new fitting orientation according to instructions given in Service Bulletin ATR 72-92-1004 (Mod. 8287) or any further approved revision.

REF.: Service Bulletin ATR 72-92-1004 original issue dated January 26, 2001

Any further approved revision of this SB is acceptable.

EFFECTIVE DATA: Upon receipt from FEBRUARY 07, 2001