SAIB NM-15-14

FAA Aviation Safety

SPECIAL AIRWORTHINESS

INFORMATION BULLETIN SUBJ: Propellers/Propulsors SAIB: NM-15-14 Date: April 20, 2015 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin advises owners and operators of ATR – GIE Avions de Transport Régional Model ATR42-500 and ATR72-212A airplanes equipped with Hamilton Sundstrand Model 568F-1 propellers of sudden and severe propeller vibrations during descent or approach phases.

At this time, the airworthiness concern is not an unsafe condition that would warrant an FAA airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39.

Background

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union, has issued Safety Information Bulletin (SIB) 2015-03, dated January 30, 2015. The SIB provides information on incidents, found during maintenance troubleshooting, of sudden and severe propeller vibrations during the descent performed at a speed close to Velocity, Maximum Operation (VMO) with power levers in Flight Idle position, associated with Propeller Electronic Control (PEC) fault messages (Code 67 & 68). Based on these incidents, EASA issued the SIB to improve crew awareness and allow better and timely identification of this type of vibration, in order to apply appropriate actions.

Recommendations

The FAA recommends that all owners and operators of the airplanes identified above follow the instructions outlined in ATR Operators Information Message (OIM) 2014/10, Issue 1, dated September 23, 2014; and UTC Aerospace Systems Service Bulletin 568F-61-67, dated October 2, 2014. The instructions include measuring the blade angle backlash on all six blades of the 568F-1 propeller; and removing the actuator and measuring the distance between the ears of the actuator forward and aft yoke plates, if necessary. The instructions also provide guidelines to follow if sudden and severe propeller vibrations occur.

We request that owners and operators report any damage found on the propeller pitch change mechanism (blade trunnion pin broken or cracked, actuator forward yoke plate bent or damaged) to ATR - GIE Avions de Transport Régional, as specified under “Related Service Information Contact” below. Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection contained in this SAIB, and assigned OMB Control Number 2120-0731.

For Further Information Contact

Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, Transport Airplane Directorate, FAA; 1601 Lind Ave. SW, Renton, Washington, 98057-3356; telephone: 425-227-1137;

fax: 425-227-1149; e-mail: tom.rodriguez@faa.gov.

For Related Service Information Contact

ATR - GIE Avions de Transport Régional, Continued Airworthiness Service; telephone:

+33 (0)5 62 21 62 21 - fax: +33 (0) 5 62 21 67 18; e-mail: continued.airworthiness@atr.fr.