Aircraft
Certification Service Washington, DC U.S. Department of Transportation Federal Aviation Administration
CE-12-27
April 16, 2012
This is information only. Recommendations
aren’t mandatory.
Introduction
This Special Airworthiness Information Bulletin informs you of an
airworthiness concern that is relevant to all airplanes equipped with a
restraint system. This includes airplanes certificated under Title 14
of the Code of Federal Regulations (14 CFR) part 23, as well as those
certificated under the previous Civil Air Regulations (CAR) part 3.
This information is also relevant to any special lightsport category
airplanes (S-LSA), experimental light-sport airplanes (E-LSA), and
experimental amateur-built airplanes.
At this time, the Federal Aviation Administration (FAA) has determined
that this airworthiness concern is not an unsafe condition that would
warrant airworthiness directive (AD) action under 14 CFR part 39.
Background
In 2011, the National Transportation Safety Board (NTSB) released a
safety study titled Airbag Performance in General Aviation Restraint
Systems. The study investigated the safety enhancing ability of
inflatable restraint systems that, as of August 2010, are installed in
nearly 18,000 seats of 7,000 general aviation (GA) airplanes. This
study focused on 10 aircraft accidents, of which 7 had airbag
deployments. Two of these accidents resulted in a specific
recommendation from the NTSB. Although the study was focused on
inflatable restraints, the resulting recommendation isn’t specific to
inflatables. The NTSB recommendation and the FAA’s concerns apply to
any type of restraint.
The first accident involved a Cessna Aircraft Company (Cessna) Model
T182T airplane. The inflatable three-point restraints did not deploy
for any of the three occupants. This was due to the impact direction
being more downward than forward, so no deployment was expected. All
three occupants survived the crash with serious to minor injuries.
However, post-crash interviews with the pilot revealed that before
takeoff the front left seat passenger had incorrectly attempted to use
the restraint for the right seat. The pilot, a certified flight
instructor, indicated that there had been other occasions in Cessna
Models 172 and 182 airplanes where his students had inadvertently used
the wrong restraint.
In certain Cessna-manufactured airplanes, passengers may incorrectly
fasten the restraints such that the wrong airbag activates. Since the
above accident, AmSafe, the inflatable restraint manufacturer, issued a
supplement to the operating handbook for Cessna Models Skyhawk (172R,
172S), Skylane (182S, 182T, T182T), and Stationair (206H, T206H)
airplanes to include a reference to a warning label on the lap portion
of the restraint. Additionally, Cessna issued a service bulletin to
owners of airbag-equipped Cessna aircraft to document the changes to
the pilot’s operating handbook.
Figure 1, below shows the correct (left) and incorrect (right) way to
fasten the three-point inflatable restraint. For example, in the
picture on the right, if an occupant in the left seat fastens the right
seat restraint to his or her outboard buckle, the airbag system in the
unused restraint would be active while the airbag in the buckled
restraint would be inactive.
The second accident involved a Cirrus Design Corporation (Cirrus) Model
SR-22 airplane with fourpoint inflatable restraints as shown in Figure
2 below. Figure 2 shows how the belts hang in the relaxed and
unfastened condition with the buckles resting high above a proper
latched and secured position that would be low and tight across the
occupant’s hips. In the accident, all four occupants survived, but
three of the four occupants appear to have incorrectly fastened the
restraint such that the buckle rested on the chest, on or just below
the sternum, as shown by the arrows on Figure 3. Figure 3 shows the
proper position of the buckle, low and tight across the hips. One
occupant stated that they always wore the restraint in this fashion,
with the buckle positioned over the chest area. The bruising on the
chest of the occupants was likely due to the incorrectly positioned
buckle. Also, some of the facial injuries were likely due to the closer
proximity of the occupants face to the rapidly deploying airbag, a
result of incorrect positioning of the restraint system. The Cirrus
SR-22 pilot’s operating handbook gives correct and specific
instructions on proper fastening of the restraint system, which
includes “…the lap buckle centered and tightened around the hips.”
The FAA recommends that the pilot and passengers assure they use the
airplane seat restraints properly. Inflatable restraints aren’t in any
way unsafe. On the contrary, they provide additional life saving
benefits. However, if any restraint is not properly used, then its life
saving benefits may not be realized. This applies to both conventional
and inflatable restraints.
The FAA wants to clarify that when operating an aircraft under Title 14
Code of Federal Regulations (CFR), part 91, §91.107(a)(1) and (2)
(see below), it is the pilot in command’s responsibility to ensure that
all passengers are instructed on the proper use of the seat restraint
system and to fasten them prior to take off.
Sec. 91.107
Use of safety belts, shoulder harnesses, and child restraint systems.
(a) Unless otherwise authorized by the Administrator--
(1) No pilot may take off a U.S.-registered civil aircraft (except a
free balloon that incorporates a basket or gondola, or an airship type
certificated before November 2, 1987) unless the pilot in command of
that aircraft ensures that each person on board is briefed on how to
fasten and unfasten that person's safety belt and, if installed,
shoulder harness.
(2) No pilot may cause to be moved on the surface, take off, or land a
U.S.-registered civil aircraft (except a free balloon that incorporates
a basket or gondola, or an airship type certificated before November 2,
1987) unless the pilot in command of that aircraft ensures that each
person on board has been notified to fasten his or her safety belt and,
if installed, his or her shoulder harness.
There are clear instructions in the pilot’s operating handbook, which
is available to the pilot in command, on the proper use of these
systems.
For Further Information Contact
Mark James, Aerospace Engineer, 901 Locust, Room 301, Kansas City, MO
64106; phone: (816) 329-4137; fax: (816) 329-4090; email:
mark.james@faa.gov.
