Engine Oil Pressure; Torque Transducer Oil Pressure Pipe P-Clamp Installation

1 FAA Aviation Safety SPECIAL AIRWORTHINESS INFORMATION BULLETIN SUBJ: Engine Oil Pressure; Torque Transducer Oil Pressure Pipe P-Clamp Installation SAIB: CE-17-13 Date: May 19, 2017 This is information only. Recommendations aren’t mandatory.

Introduction

This Special Airworthiness Information Bulletin is to alert owners, operators, maintenance technicians, and inspectors of an airworthiness concern on Pilatus Aircraft (Pilatus) Models PC-12, PC-12/45, PC-12/47 and PC-12/47E airplanes with respect to the importance of the correct installation of the torque transducer oil pressure pipes.

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

Background

An occurrence was reported on a Pilatus Model PC-12/47 airplane where oil pressure and oil temperature warnings were activated and eventually the engine suffered internal damage caused by oil starvation. Investigation results identified that the P-clamps on the torque transducer oil pressure pipes were not installed as instructed in the applicable aircraft maintenance manual (AMM).

Incorrect installation, in particular wrongly installed or missing P-clamps, may result in loosening of the torque transducer oil pressure pipes with consequent loss of engine oil, erroneously low engine torque indication, and the inability of the engine torque limiter to properly limit engine output. This can result in unknowingly exceeding engine output limitations and an in-flight engine shutdown.

Prompted by these findings and to prevent such events in the future, Pilatus issued PC-12 Service Letter (SL) 192, dated April 20, 2017, to highlight the importance of the correct installation of the torque transducer oil pressure pipe P-clamps. The correct P-clamp installation is shown in Figure 1 Detail B of this service bulletin. The P-clamps are identified as item 14 of the AMM.

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued Safety Information Bulletin No. 2017-06 to recommend the importance of this service letter and importance of maintaining the maintenance of the airplane following the AMM.

At this time, EASA has determined this condition to not be unsafe and does not warrant an EASA AD under their system.

2 Recommendations

For Pilatus Models PC-12, PC-12/45, PC-12/47, and PC-12/47E airplanes, we recommend owners and operators to accomplish the actions as specified in Pilatus PC-12 SL 192, and always maintain the airplane in accordance with the instructions given in the applicable AMM.

For Further Information Contact

Doug Rudolph, Aerospace Engineer Federal Aviation Administration, Small Airplane Directorate, ACE-112, 901 Locust Street, Room 301, Kansas City, MO; phone: (816) 329-4059; fax: (816) 329- 4090; e-mail: [email protected].

For Related Service Information Contact

The applicable manufacturer’s documentation may be obtained directly from: PILATUS AIRCRAFT LTD. Customer Technical Support (MCC) P.O. Box 992 CH-6371 Stans, Switzerland Tel.: +41 (0)41 619 67 74 Fax: +41 (0)41 619 67 73 Via e-mail: [email protected].