Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
SW-07-16
February 9, 2007
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) alerts
owners and operators of Robinson Helicopter Company models R22 and R44
that the rotor blade skin may begin to debond at the skin-to-spar joint
on the lower surface at the tip. The Robinson Helicopter Company has
issued a safety alert warning of this condition. It is available on the
company web site at www.robinsonheli.com. This SAIB applies to all R22,
R22 Alpha, R22 Beta, R22 Mariner, R44, and R44 II helicopters with main
rotor blades part number A016-4, C016-2 or C016-5.
Background
Four R22 A016-4 blades skins have been found debonded at the
outboard tip lower surface where the skin butts up against the spar.
Six similar debonds have occurred on R44 blades, part number C016-2.
The debond can occur when either the paint is eroded enough to expose
the leading edge of the lower skin, or if corrosion is present at the
blade tip. Preflight inspection of this area should allow early
detection of a debond and prevent a catastrophic failure.
Recommendation
During daily preflight inspections carefully inspect the lower
skin-to-spar joint area, especially the outboard 10 inches (See
Robinson Safety Alert dated 04 January 2007 for the location). If any
area of the skin is not flush with the spar, the blade should be
considered un-airworthy. On blades with paint still covering the
skin-to-spar joint, a crack in the paint may indicate a debond. If any
indication of a debond is detected, a “tap test” by a qualified
mechanic should be performed prior to further flight to detect an
actual disbond. If any indication of a debond is detected, the blade
should be considered unairworthy.
If unusual rotor system noise or vibration is detected in flight, land immediately and inspect blades.
For Further Information Contact
Los Angeles Aircraft Certification Office, 3960 Paramount Boulevard, Lakewood, California 90712
For R22:
Mr. Eric Schrieber, Aerospace Engineer; phone: (562) 627-5348; fax: (562) 627-5210 email: eric.schrieber@faa.gov
For R44:
Mr. Fred Guerin, Aerospace Engineer; phone: (562) 627-5232; fax: (562) 627-5210 email: fred.guerin@faa.gov