AD Focuses On Main Rotor Fixing Bolts
The FAA has released an Emergency Airworthiness Directive (AD)
(2010-02-51) prompted by a mandatory continuing airworthiness
information (MCAI) AD issued by the European Aviation Safety Agency
(EASA), the Technical Agent for the Member States of the European
The MCAI states that 2 of the 3 installed main rotor scissor
fitting assembly fixing bolts (fixing bolts) on a Model A109K2
helicopter had cracked in flight. Investigation by the manufacturer
revealed that the crack was caused by inadequate instructions for
installing the bolts. Improper installation of the main rotor
scissor fitting assembly, if not detected and corrected, could
result in a crack in a fixing bolt, failure of the fixing bolt, and
subsequent loss of control of the helicopter.
The FAA has reviewed Agusta Alert Bollettino Tecnico (ABT) No.
109K-53 for Model A109K2 helicopters and ABT No. 109-131 for Model
A109A, A109A II, and A109C helicopters, both dated December 18,
2009. The ABTs specify a one-time inspection to verify the correct
installation of the main rotor scissor fitting assembly, part
number (P/N) 109-0110-67 or P/N 109-0101-58, to determine if 2
washers are installed under the head of each fixing bolt. If 2
washers are not installed under the head of each fixing bolt, the
ABTs specify replacing each fixing bolt with an airworthy fixing
bolt, P/N 109-0101-78-5, and installing 2 washers under the head of
each fixing bolt.
EASA has issued AD No. 2009-0274-E, dated December 18, 2009, to
correct an unsafe condition for the specified Agusta model
helicopters. EASA advises that failure of a fixing bolt could lead
to loss of control of the helicopter.
These helicopter models have been approved by the aviation
authority of Italy and are approved for operation in the United
States. Pursuant to our bilateral agreement with Italy, EASA, their
technical agent, has notified us of the unsafe condition described
in the MCAI AD. We are issuing this AD because we evaluated all
information provided by EASA and determined the unsafe condition
exists and is likely to exist or develop on other helicopters
of these same type designs. Therefore, this AD requires, within 5
hours time-in-service (TIS), inspecting the main rotor scissor
fitting assembly to determine if there are 2 washers installed
under the head of each fixing bolt. If there are 2 washers
installed under the head of each fixing bolt, no further
action is required.
If there are not 2 washers installed under the head of each
fixing bolt, this AD requires, within 25 hours TIS after complying
with paragraph (a) of this AD, replacing each fixing bolt and
installing 2 washers under the head of each fixing bolt.
This AD differs from the MCAI AD in that we refer to
“flight hours” as “hours TIS”. Also, the
FAA does not allow an optional date for replacing the fixing