VI.A.6. Subpart J - Special Airworthiness Requirements
Internal doors. Section 121.217 prescribes that in any case
where internal doors are equipped with louvers or other ventilating
means, there must be a means convenient to the crew for closing the
flow of air through the door when necessary.
Comments: Raytheon Aircraft states that a new toilet
installation for the 1900D has internal partitions with permanently
open louvers. Compliance with § 121.217 would require Raytheon to
redesign the partition louvers so a crewmember could leave his or her
station to close the louvers when necessary or design the louvers for
remote control closure.
FAA Response: Contrary to the commenter's assumption, the
lavatory partition louvers in the commenter's airplanes would not have
to be redesigned. As stated in § 121.213(a) and (b), § 121.217
applies only to airplanes type certificated under Aero Bulletin 7A or
part 04 of the Civil Air Regulations.
Cargo carried in the passenger compartment. Section 121.285
requires that cargo carried in passenger compartments must be stowed
in a fully enclosed bin or carried aft of a bulkhead or divider and
properly restrained. Section 135.87 allows certificate holders to
carry cargo in an approved cargo compartment instead of a fully
enclosed bin and to carry restrained cargo anywhere in the passenger if it is restrained by a net that meets the requirements
of § 23.787(e). The FAA proposed to amend § 121.285 to add an
exception for commuter category (and predecessor) airplanes that would
have the effect of allowing cargo to be carried in the passenger
compartment as it is today under part 135.
Comments: AACA, an association of Alaskan air carriers, fully
supports the proposal.
FAA Response: The final rule includes provisions from § 135.87
that have been moved into § 121.285 for nontransport category
airplanes type certificated after December 31, 1964.
Landing gear aural warning device. Section 121.289 contains a
requirement for a landing gear aural warning device for large
airplanes. At present this section applies to any airplane with a
maximum certificated takeoff weight of more than 12,500 pounds.
Appendix A of part 135 requires a landing gear warning device for
airplanes having retractable landing gear and wing flaps, but the
device need not be aural. The FAA considers that the cost of
replacing a warning light with a warning sound would be minimal.
Therefore, this section would apply to any airplane that presently
operates under part 135 and that would be required by this final rule
to operate under part 121. To allow adequate time for airplanes
without aural warning devices to be retrofitted, the FAA proposed a
compliance date of 2 years after the publication date of the final
Comments: Raytheon comments that their models all provide aural
landing gear warning.
AACA notes that the FAA did not prepare a cost analysis for this
proposal, other than to show that the cost would be "minimal." AACA
shows that various manufacturers' comments on similar proposals have
identified substantial administrative, engineering, installation, and
ongoing maintenance cost. However, AACA also notes that, in this
case, Fairchild Aircraft believes that the landing gear aural warning
can be installed without undue cost or difficulty.
AACA also states that once an item is installed, there are many
other things that must be done that involve cost. Cost items
identified are: revisions of the certificate holder's training
program, normal and emergency procedures, maintenance MEL's and other
items need to be amended to reflect the change from a visible lighted
warning device to an aural device. According to AACA, compliance
costs add up incrementally to substantial cumulative cost and that the
FAA fails to account for.
FAA Response: Even though part 23 requires an "aural or equally
effective device," the FAA is not aware of airplanes where the
"equally effective device" was accepted as the only warning for the
landing gear warning. The reason for not accepting such devices
includes the consideration of pilot's work load during the landing
phase of flight and the need for the warning to attract pilot
attention under such conditions. No proposed lighted device, by
itself, has been found acceptable to provide the needed warning for
this flight condition. Therefore, the FAA is amending § 121.289 as
proposed to require installation of a landing gear aural warning
device within 2 years of the publication of this final rule. However,
the FAA believes that all affected airplanes already have an aural
Emergency evacuation and ditching demonstrations. Section
121.291 contains requirements for conducting demonstrations of
airplane evacuation and ditching procedures. The FAA requires these
demonstrations upon introduction of a new type and model of airplane
into passenger-carrying operations. For airplanes with a seating
capacity of more than 44 passengers, an actual evacuation
demonstration must show that the full capacity of the airplane and the
crewmembers can be evacuated within 90 seconds. Also, for airplanes
with more than 44 passenger seats a partial demonstration is required
under one of the circumstances described in § 121.291(b).
Demonstrations have not been required for airplanes with fewer than 44
Under § 121.291(d) any certificate holder operating or proposing
to operate one or more landplanes of any size in extended overwater
operations must conduct a simulated ditching in accordance with
Appendix D to part 121. The purpose of the ditching demonstration is
to show that the certificate holder's ditching training and procedures
for a new type and model of airplane are satisfactory. The simulated
ditching does not specifically require the use of flight attendants;
the FAA proposed to apply this rule to any affected commuter operator
who conducts extended overwater operations, whether or not flight
attendants are used in the operation. The FAA proposed to apply this
provision to the affected commuter operators only when a new type and
model of airplane is introduced into the certificate holder's
operations after the effective date of the final rule. This
requirement does not apply to the current fleet.
The FAA proposed to amend § 121.291(b) to clarify that the
partial demonstration procedures apply only to airplanes with more
than 44 passenger seats.
Comments: With respect to partial evacuation, one commenter
states that the proposed rule would reduce the safety requirements for
commuters because the evacuation procedures under part 121 do not
apply to airplanes with less than 44 seats and that § 23.803 requires
a demonstration for commuter category airplanes. One commenter states
that § 121.291(b) does not indicate if the requirement applies to
aircraft with more than 44 seats or all aircraft.
Two commenters recommend clarifying the rule language for the
ditching demonstration in § 121.291(d) to make the FAA's intent clear.
The commenters say that the current language does not properly
communicate the fact that a ditching demonstration would be required
only if an airplane is a new make/model for a particular certificate
FAA Response: Parts 25 and 121 currently require emergency
evacuation demonstrations for transport category airplanes with more
than 44 passenger seats. These demonstrations are required in
addition to specific detail design requirements, e.g. aisle width,
exit size, exit slides, etc., and are conducted to confirm the overall
evacuation capability of the airplane. They are also conducted to
show the adequacy of the operator's evacuation procedures.
Considering the specific detail design requirements with which
transport category airplanes must also comply, the FAA has not found
it necessary to require such evacuation demonstrations for airplanes
having 44 or fewer passenger seats. Since part 135 does not pertain
to operations with airplanes having more than 44 passenger seats,
there has been no need to require an emergency evacuation
demonstration in that part. Part 23, on the other hand, does not
contain the same specific detail design requirements for commuter or
predecessor normal category airplanes. Therefore, an evacuation
demonstration is required for type certification of those airplanes in
lieu of the specific detail design requirements that transport
category airplanes must meet. There will be no reduction in safety
because transport category airplanes will still be required to comply
with the same specific detail design requirements and the part 23
requirement for an evacuation demonstration will remain unchanged. As
proposed, § 121.291(b) is amended to make clear that it, as well as
§ 121.291(a), only applies to airplanes with more than 44 passenger
The FAA agrees that the language in § 121.291(d) for the ditching
requirement does not clearly state that it applies to the affected
commuters only if an airplane is a new type and model introduced after
they began operations under part 121. Therefore, clarifying language
is added to § 121.291(d).
New special airworthiness requirements (retrofit) and
requirements applicable to future manufactured airplanes:
Ditching emergency exits. Section 25.807(e) contains
requirements for ditching emergency exits in transport category
airplanes. The ditching exits for transport category airplanes with
10 or more passenger seats must meet at least the dimensions of a Type
III passenger emergency exit (20 inches wide by 36 inches high). It
should be noted that transport category airplanes are required to have
ditching exits meeting those criteria regardless of whether the
airplane is approved for ditching and used in extended overwater
operations. If ditching approval is requested by the applicant, it
also must be shown that the required life rafts can be launched
successfully through the ditching emergency exits.
Part 23, as recently amended by Amendment 23-46 (59 FR 25772; May
17, 1994), now contains requirements for ditching exits; however, all
of the normal or commuter category airplanes currently in service were
type certificated before that amendment became effective. The FAA
proposed to amend part 121 (proposed new § 121.293(a)) to require
ditching exits for nontransport category airplanes type certificated
after December 31, 1964. Unlike those required for transport category
airplanes, the ditching exits would only have to be as large as those
currently required by § 23.807(b) (19 inch by 26 inch ellipses). The
FAA proposed that compliance would be required 2 years after the
publication date of the final rule. The proposed requirement would
not entail adding new exits. The overwing exits of most airplanes
type certificated under part 23 would probably qualify as ditching
exits. Part 25 airplanes intended for non-part 121 transportation
sometimes comply by providing a sheet metal dam that can be installed
in the passenger entry doorway. If it is necessary to consider a
floor-level exit as a ditching exit in a nontransport category
airplane, a similar sheet metal dam could be provided.
Comments: Commuter Air Technology, a modifier of business
airplanes for commuter airline service, states that its product has
overwing exits that would be usable anytime the airplane was floating.
The commenter questions whether it would be necessary to conduct a
$5,000 type certification effort to qualify those exits as ditching
emergency exits. NATA, an association representing certificate
holders of 10-to-19 passenger seat airplanes, recommends rescinding
the proposal and asserts that the cost of compliance would be
extremely high. The commenter offers no specific details concerning
costs, but does note that de Havilland DHC-6 Twin Otters have
experienced only three ditchings in 17 million flight hours.
FAA Response: The comments received have some validity. The
majority of the current commuter fleet, at least those for which
ditching exits were not substantiated for certification, includes such
airplanes as the Beechcraft 99 and 1900 and Fairchild airplanes with
low wings and overwing exits. It is likely that these exits would
qualify as ditching emergency exits. However, they would have to be
tested. That would also be true of all other low-wing part 23 normal
or commuter category airplanes that would be operated under part 121.
In addition to the low-wing models, there are also three high-
wing normal or commuter category airplane models. These are de
Havilland DHC-6, Twin Otters, which are by far the most numerous of
the high-wing models, and the Dornier 228 and Britten Norman BN-2A Mk
III Trislanders. (This, of course, refers to landplanes. Many Twin
Otters operate as seaplanes on floats.) Typically, high-wing
landplanes come to rest in the water on the fuselage with one wing tip
in the water.
The DHC-6 Series 100 and 200 airplanes have emergency exits in
the top of the fuselage forward of the wing. These exits also meet the
ditching emergency exit requirements. The DHC-6 Series 300 airplanes
do not have such overhead exits; instead they depend entirely on the
emergency exits in the sides of the fuselage. In almost three decades
of service with Twin Otters, there have been two ditchings. One
involving a Series 100 airplane occurred in the Pacific Ocean during a
ferry flight from Long Beach, California, to Honolulu, Hawaii.
Another, involving a Series 300, occurred in the Arctic. In both
instances, all occupants were evacuated safely. In the latter case,
the occupants escaped through the exits on the highest side. The FAA
is not aware of any ditchings of Trislanders or Dornier 228 airplanes;
however, because the Dornier 228 and the Trislander are so similar in
design to the DHC-6, it is likely that they would float the same way
that the Series 300 airplane did, and that their exits would also meet
the ditching emergency exit requirements.
Most of the part 23 commuter and predecessor normal category
airplanes are low-wing airplanes with overwing exits that would comply
with no further substantiation required. The vast majority of the
airplanes would, therefore, not be affected by the requirement in
regard to either cost or safety benefit because they already comply.
In view of the successful ditchings that have occurred with high wing
airplanes to date, the FAA has decided not to adopt § 121.293(a) as
Takeoff warning system. Section 25.703 requires an aural
warning to the flightcrew at the beginning of the takeoff roll when
the wing flaps, leading edge devices, wing spoilers, speed brakes, and
longitudinal trim devices are not in a position that would allow a
safe takeoff. Part 23 does not require a takeoff warning system
(although a requirement for such a system is proposed in Notice No.
94-21, 59 FR 37620, July 22, 1994); in addition, part 23 airplanes
typically do not have multiple types of devices. Accidents have
occurred on transport category airplanes when the flightcrews
initiated takeoffs when the airplanes were not in the proper
configurations for takeoff. The FAA proposed that airplanes
manufactured after a date 4 years after the publication date of the
final rule would be required to have a takeoff warning system as
required by § 25.703. However, a warning system is not required for
any device for which it can be demonstrated that takeoff with that
device in the most adverse position would not create a hazardous
condition (§ 121.293(b)).
Comments: One commenter notes that a takeoff warning would not
be required under § 25.703 if it is demonstrated that a takeoff with
that device in the most adverse position would not create a hazardous
condition. This commenter questions how one can measure the effect of
these improper settings when compounded by other unfavorable
conditions, such as weight and balance mistakes, but does not express
support or opposition to the proposal.
Commuter Air Technology discusses the longitudinal trim and flap
systems on its airplanes. The commenter notes that the pilot can
visually verify that the flaps are in correct 40 takeoff setting from
the cockpit. The commenter also states that the longitudinal trim is
manual and has center marking visible from both the pilot and co-pilot
positions. The commenter's position is that the additional cost of
such a system is not warranted.
FAA Response: The first commenter correctly notes that a takeoff
warning system is not required for any devices if it is demonstrated
that takeoffs with that device in the most adverse position would not
cause an unsafe condition. While the FAA agrees that with some
airplanes it is possible to verify visually flap positions and manual
trims and that there is a cost to install warnings, the FAA has
determined that for safety reasons, an aural warning is needed under
the conditions described.
In considering these comments, the FAA notes that all of the in-
service airplanes have demonstrated, by their service histories, that
there is no device position that would cause an unsafe condition and
therefore that there would be no need for installation of additional
takeoff warning devices. While proposed § 121.293(b) (now § 121.293)
does not apply to any in- service airplanes affected by this rule, the
requirement for airplanes manufactured 4 years after the publication
date of this rule is retained in the final rule to ensure that future
airplanes are covered.