Airworthiness Directives; Aerospatiale Model ATR 42, et al.; Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 89-NM-205-AD]

Airworthiness Directives; Aerospatiale Model ATR 42, et al.;

Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Proposed rule; withdrawal.

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SUMMARY: This action withdraws a notice of proposed rulemaking (NPRM)

that proposed a new airworthiness directive (AD), applicable to various

smaller transport category airplanes certificated for operation with a

main deck Class B cargo compartment. That action would have required

either the conversion of all main deck Class B cargo compartments to

the Class C configuration; or the use of flame penetration-resistant

containers with smoke detection and fire extinguishing systems to carry

all cargo; or the accomplishment of certain operational and equipment

changes and design modifications to maximize cargo fire detection and

control. Since the issuance of the NPRM, the Federal Aviation

Administration (FAA) has received new data and is undertaking

alternative rulemaking action. Accordingly, the proposed rule is

withdrawn.

FOR FURTHER INFORMATION CONTACT: Mark Quam, Aerospace Engineer,

Standardization Branch, ANM-113, FAA, Transport Airplane Directorate,

1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (206)

227-2145; fax (206) 227-1320.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal

Aviation Regulations to add a new airworthiness directive (AD),

applicable to various smaller transport category airplanes certificated

for operation with a main deck Class B cargo compartment, was published

in the Federal Register on September 5, 1990 (55 FR 36284). The

proposed rule would have required either the conversion of all main

deck Class B cargo compartments to a Class C configuration; or the use

of flame penetration-resistant containers with smoke detection and fire

extinguishing systems to carry all cargo; or the accomplishment of

certain operational and equipment changes and design modifications to

maximize cargo fire detection and control. That action was prompted by

a report of an uncontained fire in a main deck cargo compartment on a

transport category airplane. The proposed actions were intended to

prevent an uncontrolled cargo fire that could cause extensive damage to

the systems and structure of the airplane.

Since the issuance of that NPRM, the FAA has received additional

data and has initiated other rulemaking activity, which has caused it

to reconsider its previous position on this rulemaking action.

The FAA received over 128 comments and suggestions to the proposal,

including ones from affected operators, aircraft manufacturers,

industry representatives, and civil aviation authorities from around

the world. The general nature of almost all of the comments received

was in disagreement with the issuance of the proposed rule.

One commenter requests that further action on this AD be postponed

until the proposed actions have been carefully coordinated with the

aviation authorities of the countries controlling the type certificates

of the applicable aircraft. The FAA notes that, during the development

of this proposal, it apprised foreign civil airworthiness authorities

(FCAA) of the planned actions. The FAA has given due consideration to

the comments and recommendations that were received from each of these

FCAA's.

Many commenters question the justification for the proposed rule

and request that it be withdrawn. Five commenters question the FAA's

method of requiring change via an AD. Several commenters consider that

the proposed rule fails to meet the regulatory requirements of

Sec. 39.1 (``Airworthiness Directives; Applicability'') of the Federal

Aviation Regulations (14 CFR 39.1); these commenters contend that the

FAA has not established that the unsafe condition is likely to exist or

develop on the affected airplanes. One commenter points out that a

review of the FAA's Service Difficulty Reports (SDR) failed to disclose

any problem with regard to detection, access to, or control of smoke or

fires in baggage compartments of airplanes of the type and size

affected by the proposal. One of these commenters points out that there

is no service history to suggest that compartments of this size [under

400 cubic feet] have been or are likely to be a fire hazard. Four

commenters consider that the FAA's intent in proposing the AD should

instead be addressed either as a change to affected operators'

Operation Specifications or as a change to part 121 (``Certification

and Operations: Domestic, Flag, and Supplemental Air Carriers and

commercial Operators of Large Aircraft'') of the Federal Aviation

Regulations (14 CFR part 121).

The FAA agrees with certain observations made by these commenters.

The FAA has conducted a review the SDR's as well as the United Kingdom

Civil Airworthiness Authority's (CAA) World Airline Accident Summary

and found no reports of incidents or accidents caused by fire in the

Class B cargo compartment of transport airplanes addressed by this

notice. The historical data that was reviewed indicates only that there

has not been a cargo compartment fire in the size of airplanes

specified in the notice. However, the lack of incidents of fire does

not establish that the Class B compartment, as defined in the existing

certification regulations, has appropriate safeguards if a fire were to

occur. It is this aspect that the proposed rule was meant to address.

Some commenters state that the smaller cargo compartments of the

airplanes affected by this proposed AD are different from the larger

compartments on the airplanes that are affected by AD 93-07-15,

amendment 39-8547 (58 FR 21243, April 20, 1993), since those

compartments contain pallets and/or containers. One commenter states

that the smaller cargo compartments used in commuter service have not

been established to be similar, from the standpoint of safety, to main

deck Class B compartments of larger transports; therefore, any action

to address fire safety should concentrate on large ``Combi'' cargo

compartments, as in AD 93-07-15. Another commenter considers that the

fire detection problems that may exist on jumbo-jet airplanes do not

have any relevance for smaller airplanes. Another commenter states that

the hazard of carrying large pallets/containers in increasingly large

``Combi'' compartments is the issue to be addressed, not the size of

the compartment itself.

The FAA disagrees that the smaller cargo compartments are not

similar, with regard to fire safety, to the larger compartments

containing pallets or containers. On the smaller transport airplanes,

cargo and luggage are loaded in a manner such that smoke detection and

access may be inhibited if the fire is deep-seated (buried in the

cargo), much the same as in a container or pallet on a larger transport

airplane. Further, the FAA has observed, and one commenter to the

notice admitted, that in many instances, some operators of the smaller

transport airplanes load the airplane's cargo compartments in such a

manner that there is no place to displace the cargo within the

compartment in order to get at a fire. This presents a two-fold hazard:

1. The fire cannot be accessed and continues to burn; and

2. If cargo is removed from the cargo compartment, passengers could

be exposed to fire, toxic smoke, and fumes; this situation is unsafe

and contrary to the concept and rule requirements of the Class B cargo

compartment.

Four commenters provide information concerning the economic effects

of the proposed AD. One of these commenters, an operator, states that

it has had a long-term investment in its combi operations; however, if

the rule is issued, any further ``Combi'' operations would be cost-

prohibitive for this operator. This would force the operator to raise

passenger ticket prices, and resort to less frequent all-passenger or

all-cargo flights. Another commenter states that the proposed

requirements of the rule would have a devastating effect on service to

remote communities that have no alternative means of transport

available. Another commenter states that it would cost up to $200,000

per airplane to accomplish the requirement to convert the cargo

compartment to a Class C configuration; this would be a great economic

burden for small operators. Another commenter estimated that the

requirements of the proposed rule would cost 10% of its annual gross

revenues.

In light of these comments and other information provided, the FAA

must continue to consider the following aspects relevant to this

rulemaking action:

1. A service history indicating that there has not been a fire in

the Class B cargo compartments of the size of aircraft addressed by the

proposed rule; and

2. Cargo loading practices on the smaller transport category

airplanes that may inhibit smoke detection and negate access

requirements of the Class B cargo compartment.

Because of the potentially catastrophic consequences of fire in

Class B cargo compartments and the impossibility of eliminating the

potential for such fires, the FAA cannot conclude that the existing

Class B compartments do not present an unsafe condition. However, this

condition is a result of flaws in the underlying design standards for

these compartments, and correcting those flaws may have significant

economic and operational consequences. For these reasons, the FAA has

concluded that issuance of an AD to address this condition is not

warranted at this time.

The FAA now considers that a change to part 25 (``Airworthiness

Standards: Transport Category Airplanes'') of the FAR (14 CFR part 25)

and to the relevant operating regulations of the FAR to address these

issues is more appropriate and will allow further public participation

in the rulemaking process.

In 1989, just prior to the time that the notice was published, a

subgroup of the Department of Transportation Task Force on FAA Reform

recommended that a Standing Advisory Committee for Rulemaking be

established. The Secretary of Transportation approved this

recommendation, and the Aviation Rulemaking Advisory Committee (ARAC)

was chartered in 1991. The purpose of the committee is to provide

advice and recommendations to the FAA concerning the full range of the

FAA's rulemaking activity with respect to safety-related issues. The

expected benefits of ARAC are to take advantage of the industry

technical expertise and experience, to resolve controversies in an open

forum, to resolve issues before formal rulemaking, and to broaden

public participation in the process.

The FAA has asked ARAC to consider 70 rulemaking issues, one of

which is rulemaking relative to the Class B cargo compartment. A

``Class B Cargo Compartment Harmonization Working Group'' was

established recently to formulate and harmonize an international

position on amended requirements for the Class B cargo compartment as

installed on transport category airplanes. In its deliberations, ARAC

currently is considering the safety issues related to the Class B cargo

compartment, appropriate rule requirements, necessary rule changes,

estimated costs, and comments and advice from the aviation industry.

In light of this other on-going rulemaking activity, the FAA hereby

withdraws the proposed AD.

Withdrawal of this notice of proposed rulemaking constitutes only

such action, and does not preclude the agency from issuing another

notice in the future, nor does it commit the agency to any course of

action in the future.

Since this action only withdraws a notice of proposed rulemaking,

it is neither a proposed nor a final rule and therefore, is not covered

under Executive Order 12866, the Regulatory Flexibility Act, or DOT

Regulatory Policies and Procedures (44 FR 11034, February 26, 1979).

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Withdrawal

Accordingly, the notice of proposed rulemaking, Docket 89-NM-205-

AD, published in the Federal Register on September 5, 1990 (55 FR

36284), is withdrawn.

Issued in Renton, Washington, on May 31, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-13629 Filed 6-3-94; 8:45 am]

BILLING CODE 4910-13-U