AL 2005-07
4 August 2005
Models AS 350 and AS 355 Series
Rotorcraft Collective Lever Lock
Transport Canada has received a Recommendation Bulletin, BR 2005/16(A), from La Direction générale de l'Aviation civile française (DGAC) which incorporates by reference, Federal Aviation Administration (FAA) - Special Airworthiness Information Bulletin (SAIB) SW-05-20, dated December 2, 2004.
The subject of the Bulletin concerns Eurocopter France (formerly Aerospatiale) AS 350 and AS 355 series rotorcraft that have after-market center console panels installed in accordance with FAA STC SH4747NM, which has been approved in Canada as STC SH93-83. The FAA has reported two incidents of the collective lever lock, Part Number (P/N) 350A27-3107-26, inadvertently engaging, preventing the collective from being raised to arrest a descent.
Transport Canada has elected to re-transmit the publication verbatim so owners, operators and maintenance organizations involved in the care and operation of these model rotorcraft, can review its content and recommendations.
Special Airworthiness Information Bulletin (SAIB)
National Aircraft Certification Service Washington, DC
U.S. Department of Transportation
Federal Aviation Administration
No. SW-05-20
December 2, 2004
http://www.faa.gov/
This is information only. Recommendations aren't mandatory.
Introduction
This Special Airworthiness Information Bulletin alerts you, owners and operators of all Eurocopter France models AS-350 and AS 355 rotorcraft that have after market center console panels installed, that preliminary investigations reveal a potentially hazardous situation in which the collective lock strip inadvertently engages during flight maneuvers, locking the collective in the down position.
Background
There were two accidents involving the AS-350 series rotorcraft where the pilots reported that during training, when the collective was lowered, the collective lock, P/N 350A27-3107-26, inadvertently engaged. This prevented the collective from being raised to arrest the descent, resulting in subsequent impact with the terrain. The impact resulted in both rotorcraft being destroyed. Examination of other rotorcraft with the after-market center console panel installed revealed the position of the collective lock strip, P/N 350A27-3107-26, and the collective lock knob, P/N 350A77-1309-24, were extremely close, approximately 2 mm.
Additional information on the two accidents can be provided by Patrick Jones, Air Safety Investigator, National Transportation Safety Board, email: Patrick.Jones@ntsb.go; phone: 310-380-5657.
Recommendations
- Inspect the condition of the collective locking strip, P/N 350A27-3107-26, to ensure the strip has a positive spring force to hold it away from the collective knob and firmly against the center console. Inspect and ensure the rubber grommet, P/N 85007-130-015, is resting against the center console.
- To ensure proper rigging of the collective, review AS-350 collective lock rigging procedures, Work Card 67.10.00.501 without autopilot and Work Card 67.10.00.502 with autopilot.
- Ensure that there is a positive clearance (nominally 7mm) between the collective lock knob, P/N 350A77-1309-24, and the collective strip.
- Ensure the aftermarket installation is installed as to allow proper clearance for the collective lock at all times.
- We believe that there may be other non-reported incidents of this occurrence from the field, so, in order to determine the scope of this issue, if you have experienced this inadvertent locking of the collective and recovered without incident, PLEASE report it to the FAA Contact listed below.
- Ensure the collective lock spring mounting bolts are secure and torque properly, 35-44 in. lb.
For Further Information Contact
Gary Roach, Aerospace Engineer,
FAA Rotorcraft Directorate,
ASW-111 Rotorcraft
Standards Staff, Fort Worth, Texas 76193-0110; Phone: (817) 222-5130; Fax: (817) 222-5961; E-mail: gary.roach@faa.gov
Any further defects or occurrences should be reported to Transport Canada, Continuing Airworthiness, Ottawa, via the Service Difficulty Reporting program.
For further information, contact a Transport Canada Centre, or call Mr. Philip Champion-Demers Corrective Action, In-Service Investigations, Continuing Airworthiness, Ottawa. Telephone 613 941-7466 or facsimile 613 996-9178 or e-mail champip@tc.gc.ca
For Director, National Aircraft Certification
R. William Taylor
Acting Chief, Continuing Airworthiness
Note: For the electronic version of this document, please consult the following Web address: https://tc.canada.ca/en/aviation/aircraft-airworthiness/aircraft-certification