From: Subject: ANC06LA038 Date: Mon, 10 Nov 2008 00:19:49 +0100 MIME-Version: 1.0 Content-Type: multipart/related; type="text/html"; boundary="----=_NextPart_000_000A_01C942CA.0AF73550" X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_000A_01C942CA.0AF73550 Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Content-Location: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20060403X00379&key=1 ANC06LA038
NTSB Identification: ANC06LA038.
The docket is stored = in the=20 Docket Management System (DMS). Please contact Records Management = Division=20
Accident occurred Wednesday, March 22, 2006 in Mesa, = AZ
Probable=20 Cause Approval Date: 10/31/2006
Aircraft: MD Helicopters, Inc. MD = 900,=20 registration: N912LH
Injuries: 2 Uninjured.

The experimental category flight was being operated by the helicopter = manufacturer under Title 14, CFR Part 91, when the accident occurred. = The=20 commercial certificated helicopter pilot was conducting a series of = climbing and=20 descending turns while a second helicopter, flying alongside, filmed the = maneuvers. According to a safety representative for the helicopter = manufacturer,=20 all of the maneuvers were conducted within the normal limitations of the = helicopter. The maneuvers were completed uneventfully, with no in-flight = anomalies noted, and the helicopter returned to the manufacturer's base. = While=20 conducting a routine daily inspection of the helicopter in preparation = for the=20 next scheduled flight, maintenance technicians discovered damage to the = main=20 rotor hub's five pitch case assemblies, slightly aft of the upper damper = cap.=20 The damage was a result of the pitch cases striking the upper main rotor = hub=20 perimeter bolts. All five pitch cases were damaged beyond repairable = limits, and=20 were replaced. The safety representative for the helicopter manufacturer = reported that the anticipated corrective action will be to increase the=20 clearance between the pitch cases and the main rotor hub perimeter bolts = by=20 trimming additional material from the inboard and upper portion of the = main=20 rotor pitch case assemblies during the manufacturing process.

The National Transportation Safety Board determines the probable = cause(s) of=20 this accident as follows:

The manufacturer's inadequate design = clearance of=20 the main rotor blade grip pitch cases, which resulted in damage to the = pitch=20 cases when they contacted main rotor perimeter bolts during maneuvering = flight.

Full=20 narrative available

I= ndex=20 for Mar2006 | Index = of=20 months

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