AIRWORTHINESS DIRECTIVE

CAA-AD-084/2001

Date of issue: September 26, 2001

AIRCRAFT - FLIGHT CONTROLS - INSPECTION/MODIFICATION

Applicability: This Airworthiness Directive (AD) applies to ATR 42-200, -300, -320, -400, and -500 series aircraft models on which ATR modification 5339 (Service Bulletin ATR 42-27-0094) has not been embodied.

Effective date: September 26, 2001

Compliance: Required as indicated in DGAC AD 2001-387-085(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

AIRWORTHINESS DIRECTIVE

DGAC AD 2001-387-085(B)

ATR

ATR 42 aircraft

Flight controls - Normal pitch trim switches (ATA 27)

1. APPLICABILITY:

This Airworthiness Directive (AD) applies to ATR 42-200, -300, -320, -400, and -500 series aircraft models on which ATR modification 5339 (Service Bulletin ATR 42-27-0094) has not been embodied.

2. REASONS:

On January lst 2001, an ATR 42-300 experienced a temporary elevator pitch trim runaway which resulted to a nose up motion. During manual approach, following operation and released of the pitch trim, the trim warning sounded and column load steadily increased. Total time of runaway was approximately 4 seconds, at the end of which the out of trim force was heavy but easily held by one pilot. The pilot coarsely trimmed using the pitch trim switch (roller) and, in avoiding then using the roller, landed with a small amount of trim force.

Investigation found the roller mounting nut on First Officer pitch trim support loose, this possibly led to jamming on nose up trim selection. It was further confirmed that a not secured roller mounting nut could result in a roller jamming but only in nose up position.

In case of jamming of the roller, the pilot has no specific means to detect the cause of the problem, however the jamming is easily releasable and any slight movement on the roller s would unlock it.

The pitch trim runaway is manageable in all cases and the residual effort needed to land the aircraft after having stopped the trim runaway have been assessed acceptable.

The actions rendered mandatory by the present AD are intended to prevent a temporary elevator pitch trim runaway which could result from a not secured roller mounting nut on pitch trim support.

3. ACTIONS:

3.1. Within 3 months from the effective date of this AD, inspect and restore the correct fastening of the roller mounting nut on the elevator pitch trim support in accordance with the instructions of Service Bulletin ATR42-27-0093.

3.2. Within 2 years after implementation of the requirements of paragraph 3.1, or before November lst 2003, whichever occurs first modify the roller mounting nut safetying on the elevator pitch trim support according to the instructions given by Service Bulletin ATR 42-27-0094.

REF.: Service Bulletin ATR 42-27-0093

Service Bulletin ATR 42-27-0094

Any further approved revision is acceptable.

EFFECTIVE DATE: Upon receipt from SEPTEMBER 05, 2001