[Federal Register Volume 60, Number 28 (Friday, February 10, 1995)]
[Proposed Rules]
[Pages 7924-7925]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-3358]



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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 94-NM-70-AD]


Airworthiness Directives; McDonnell Douglas Model DC-10 Series 
Airplanes and Model KC-10A (Military) 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 all 
McDonnell Douglas Model DC-10 series airplanes and Model KC-10A 
(military) airplanes. That action would have required modification of 
the fuel crossfeed dump shutoff system. Since the issuance of the NPRM, 
the Federal Aviation Administration (FAA) has determined that other 
means are in place that adequately address the unsafe condition. 
Accordingly, the proposed rule is withdrawn.

FOR FURTHER INFORMATION CONTACT: Ray Vakili, Aerospace Engineer, 
Propulsion Branch, ANM-141L, FAA, Transport Airplane Directorate, Los 
Angeles Aircraft Certification Office, 3960 Paramount Boulevard, 
Lakewood, California 90712; telephone (310) 627-5262; fax (310) 627-
5210.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to add a new airworthiness 
directive (AD), applicable to all McDonnell Douglas Model DC-10 series 
airplanes and Model KC-10A (military) airplanes, was published in the 
Federal Register as a Notice of Proposed Rulemaking (NPRM) on July 27, 
1994 (59 FR 38141). The proposed rule would have required modification 
of the fuel crossfeed dump shutoff system. That action was prompted by 
an FAA determination that, in the event of a failure of the number 2 
bus tie relay and subsequent loss of the electrical power source of the 
number 2 engine, an all-engine flameout event could occur due to fuel 
starvation during or shortly after a fuel dumping operation. The 
proposed actions were intended to prevent loss of the fuel crossfeed 
dump shutoff system due to a failure of the number 2 DC bus electrical 
relay and subsequent loss of the electrical power source of the number 
2 engine.
    Interested persons have been afforded an opportunity to comment on 
the proposal. Due consideration has been given to the comments 
received.
    The majority of commenters request that the proposed rule be 
withdrawn for several reasons:
    First, the commenters reference AD 92-22-06, amendment 39-8392 (57 
FR 47570, October 19, 1992), applicable to Model MD-11 and DC-10 series 
airplanes and Model KC-10A (military) airplanes, which was cited in the 
preamble to the notice. That AD requires revising the Airplane Flight 
Manual (AFM) to include information to specify that electrical 
malfunctions may render the automatic fuel dump termination feature 
inoperative. That AD was prompted by an incident in which the fuel 
crossfeed dump shutoff system became inoperative, and fuel was dumped 
below the minimum allowable level. The commenters point out that the 
event that prompted the issuance of that AD occurred on a Model MD-11 
airplane, not a Model DC-10 series airplane. Because the design of the 
fuel shutoff system of the Model DC-10 is similar to that of the Model 
MD-11, the FAA concluded that the potential unsafe condition could 
exist with regard to those airplanes; however, there was no service 
history relevant to the Model DC-10.
    Second, the commenters indicate that the proposed modification of 
the fuel crossfeed dump shutoff system, which is described in McDonnell 
Douglas DC-10 Service Bulletin 28-208, would do nothing more than add a 
third level of redundancy to the crossfeed low level shutoff relay. In 
fact, the manufacturer, in its comments to the proposal, calls this 
modification merely ``a design enhancement'' to the automatic shut-off 
features of the fuel dump system; the manufacturer does not consider 
that an AD to mandate the modification is justified.
    Third, the commenters consider that the Model DC-10 already has 
adequate redundancy present by means of a third crew member (the flight 
engineer), who has specific required duties to monitor fuel quantity 
and associated fault indication systems during fuel dump operations. 
The commenters consider that, with this additional crew member in the 
cockpit directly managing the fuel dumping process, there is adequate 
protection against dumping fuel below the minimum level. The commenters 
also point out that, even though AD 94-07-07 [amendment 39-8865 (59 FR 
15853, April 5, 1994)] mandated a similar modification of the Model MD-
11, those airplanes are operated by a two-man crew and, therefore, do 
not have the same level of redundancy as the Model DC-10 with its 
three-man crew.
    For these reasons, the commenters contend that mandatory 
modification in accordance with the requirements of the proposed rule 
is not justified for Model DC-10 series airplanes.
    Upon further consideration, the FAA concurs. The FAA has reviewed 
the service history of Model DC-10 series airplanes with regard to the 
fuel crossfeed dump shutoff system and finds that the unsafe condition 
previously specified in the proposal is addressed adequately by:
    1. the current AFM revisions required by AD 92-22-06, and
    2. the flight engineer having specific duties associated with 
monitoring minimum fuel during dumping operations.
    Accordingly, the proposed rule is hereby withdrawn.
    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. 
[[Page 7925]] 

The Withdrawal

    Accordingly, the notice of proposed rulemaking, Docket 94-NM-70-AD, 
published in the Federal Register on July 27, 1994 (59 FR 38141), is 
withdrawn.

    Issued in Renton, Washington, on February 6, 1995.
S.R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 95-3358 Filed 2-9-95; 8:45 am]
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