Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-10-01
October 5, 2009
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin (SAIB) is to inform you
of an airworthiness concern on Cessna twin engine reciprocating engine
powered airplanes. However, this issue may be applicable to other
airplanes that use a detented fuel selector valve system.
At this time, this airworthiness concern is not an unsafe condition
that would warrant AD action under Title 14 of the Code of Federal
Regulations (14 CFR) part 39.
Background
During the fourth flight of the day, a Cessna Model 402C experienced a
total loss of engine power on both engines due to several missed
opportunities to detect, investigate, and correct an apparent lack of
detent positions in the fuel tank selector valve system. This lack of
detectable detents led to failure of the fuel tank selector valve to
move to the commanded position. This condition was not identified by
the pilot in command during preflight and normal procedures or by
maintenance personnel during maintenance inspections.
The Cessna Pilots Operating Handbook and FAA Approved Airplane Flight
Manual consistently states to “Feel for Detent” throughout the
preflight, normal, amplified, and emergency procedures sections of the
POH/AFM. Additionally, the various service and maintenance manuals
require operational checks, which include a “feel for the detents”,
binding and smooth operation, inspections and checks for condition,
security and servicing. The maintenance manual also clearly states a
Caution which advises:
“IF A DEFINITE DETENT IS NOT PRESENT IN EACH POSITION, THE SYSTEM IS IMPROPERLY ADJUSTED”
The term “Service” is used consistently throughout the Cessna
documentation to convey a multi-faceted approach to maintaining the
airplane systems. Servicing may include the need to perform tasks such
as inspection, cleaning, and lubrication at certain intervals as
defined in the maintenance manual.
Additionally, FAA Advisory Circular 43.13-1B, Chapter 8, Section 2,
Paragraph 8-34 offers the following guidance with respect to fuel tank
selector valves:
“c. Selector Handles. Check the operation of each handle or control to
see that it indicates the actual position of the selector valve to the
placard location. Movement of the selector handle should be smooth and
free of binding. Assure that stops and detents have positive action and
smooth operational feel. Worn or missing detents and stops can cause
unreliable positioning of the fuel selector valve.”
Recommendations
The FAA recommends that owners, operators, and maintenance personnel
thoroughly review, understand, and adhere to the information published
in the documentation identified above, which addresses the need to
evaluate the performance and identify the service requirements to
properly maintain the fuel tank selector valve system. Failure to do so
can have serious consequences as identified above.