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

warning system.

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

passenger seats.

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

holder's fleet.

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.