The need to highlight the potential failure resulting from damage to the tail rotor
blade by issuing this AD is understood and acknowledged. However, the practical
application and the results of the pre engine certification are arguable. Recent
discussions with other operators ( Australia and overseas) indicate that all
operators have a very good understanding of the intent of the pre engine start
inspection requirements but do not see any increase in the continuing
airworthiness of the aircraft as a result of the certification.
The issue with this AD concerns the pre engine start certification. The remainder
of the AD requirements are accepted, indeed we implemented these some time
ago as a standard inspection.
The following are considerations and observations in relation to the AD
requirements.
1. Currently the pilot must inspect and certify that the tail rotor blades are
not damaged prior to engine start. The AD is written in such a manner that there
may be occasions where the inspection of the TR blades is not possible, thereby
rendering the aircraft un-airworthy and unable to fly. This may occur in situations
such as:
a. Tail of the aircraft inaccessible due to landing area (over water, extreme
height, platform landings and uneven terrain.)
b. Extreme weather conditions such as heavy rain and wind.
c. No details are provided for the relief of the AD requirements in such
situations.
2. The detail of how the inspection is to be performed is not included.
That is, is the inspection performed with the use of ladders and stands to gain
access for a close visual inspection, or is the inspection performed from the
ground as is the situation during a preflight inspection?
3. Operational conditions may exist where the aircraft has continuous
operations where the engines are operated without shutdown for a considerable
period such as the case with firefighting operations.
I submit, that a detailed inspection performed by a LAME endorsed on type as a
daily (prior to first start of the day) will provided the necessary oversight to the
serviceability of the blades. The ?daily? inspection is to be performed with the use
of stands or ladders and a strong light source, specifically inspecting for damage
and repairing or replacing the any blade with damage (IAW AMM ICA). The pilot is
still to perform a visual inspection of the Tail rotor blades as part of the preflight
inspection (without certification for the AD).
This inspection will provide a greater level of safety as the LAME has detailed
knowledge of the damage limitations and is able to react to any deficiencies
immediately, thereby removing the potential for a pilot decision which may not be
as informed.
Justification:
1. The certification requirements for a pre engine start inspection do not
provide any additional safety to the aircraft.
2. The pre flight inspection performed by the pilot IAW the procedures in
the AFM include inspection of the tail rotor blades.
3. Whilst not specifically detailing the inspections of the blades for
damage, this implied as standard inspection and engineering practices.
Questions:
1. Is there an underlying issue with the manufacture and quality control of
these blades?
2. Has the manufacturer indicated that an alternative solution to this issue
is being considered?
3. Considering the nature of the defect, and the urgency of informing
operators, why was the effective date delayed until the 21 May 2008?
Related Comments
Total: 3
HELITALIA SpA Public SubmissionPosted: 05/28/2008
ID: FAA-2008-0490-0002
Australian Helicopters
This is comment on Rule
Airworthiness Directives: Bell Helicopter Textron Model 204B, 205A, 205A-1, 205B, 210, 212, 412, 412CF, and 412EP Helicopters
View Comment
Related Comments
Public Submission Posted: 05/28/2008 ID: FAA-2008-0490-0002
Jun 07,2008 11:59 PM ET
Public Submission Posted: 05/28/2008 ID: FAA-2008-0490-0003
Jun 07,2008 11:59 PM ET
Public Submission Posted: 06/09/2008 ID: FAA-2008-0490-0008
Jun 07,2008 11:59 PM ET