Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
SW-19-18
December 5, 2019
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin informs owners and
operators of Bell Helicopter Textron Canada Limited (Bell) Model 206L
helicopters about reports of fuselage cracking and possible loose
rivets in an area that currently has no inspection program.
At this time, the airworthiness concern is not an unsafe condition that
would warrant airworthiness directive (AD) action under Title 14 of the
Code of Federal Regulations (14 CFR) part 39. However, we are
continuing to monitor this airworthiness concern and may issue
mandatory corrective actions if necessary.
Background
There are multiple reports of cracks found in the fuselage
frame/bulkhead of Bell Model 206L helicopters upper area of fuselage
station (FS) 145.
The FAA’s Monitor Safety/Analyze Data (MSAD) data contains several
reports documenting cracks found in stiffener Part Number
206-033-107-055. The stiffener is located in the upper area of FS 142.7
where the aft cabin bulkhead and the bulkhead for the aft passenger
seat come together.
Further investigation, including reports from the Service Difficulty
Report (SDR) database, revealed additional occurrences of cracks in the
area of FS 145. The reported cracks were found by visual inspection and
were not limited exclusively to the stiffener. This area can be highly
loaded and could be subjected to movement. As a result of the movement,
it is not uncommon to find the rivets in this area “smoking” or working
and in need of replacement. Over time, the loose rivets could result in
cracking of the fuselage structure.
During parts of the progressive inspection, opening of the door
assemblies identified in Figure 1 (items 24, 24A, and 24B) is required
to inspect the most aft hardware of the pylon support assemblies for
the transmission and the forward engine mount fuselage structure.
However, there are currently no specific Service Bulletins or Notices
to inspect this area. Access to conduct a thorough inspection can also
be limited by the size of the opening. The Bell 206L Maintenance Manual
and Structural Repair Manual do not include specific damage assessment
criteria or repairs for this area. Transport Canada has issued Civil
Aviation Safety Alerts(CASA) No. 2019-05 to raise awareness of a
potential crack in the fuselage frame/bulkhead going undetected during
a scheduled maintenance inspection. The CASA is available at
https://www.tc.gc.ca/eng/civilaviation/opssvs/cracks-fuselage.html.
The FAA recommends the following for all Bell Model 206L series helicopters:
Each time the left and right
hand door assemblies identified in Figure 1 (items 24, 24A, and 24B) of
this SAIB are removed, inspect the entire internal structure of FS
142.7 to FS 155.00 for smoking and working rivets and for cracks. For
areas with limited access, the use of a mirror and flashlight as an aid
in the visual inspection is recommended. A borescope could also be used.
Use the approved Bell
Maintenance and Structural Repair Manuals (SRM) for inspecting,
repairing and the replacing defective parts that are within the scope
of authorized maintenance.
For any repairs not included in the SRM, repair in accordance with any FAA approved repair.
The FAA will continue to monitor
MSAD (SDR) related to this issue and may issue recommended or mandatory
corrective action, if necessary.
For Further Information Contact
Matthew Fuller, Aerospace Engineer, 10100 Hillwood Pkwy, Fort Worth TX,
76244; phone: (817) 222-5161; fax: (817) 222-5961; e-mail:
matthew.fuller@faa.gov.
