- EMERGENCY AIRWORTHINESS DIRECTIVE
- Aircraft Certification Service Washington, DC
- U.S. Department of Transportation
- Federal Aviation Administration
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- We post Emergency ADs on the internet at "av-info.faa.gov"
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- DATE: April 8, 2002
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- AD #: 2002-08-51
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- Transmitted as follows is emergency airworthiness directive
(AD) 2002-08-51, for the attention of all owners and operators of Airbus
Model A300 B2 and B4 series airplanes equipped with General Electric CF6-50
engines.
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- Background
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- The FAA has received a report that, on February 16, 2002,
uncommanded deployment of a thrust reverser occurred on the number 1 engine
of a McDonnell Douglas Model DC-10-30 airplane equipped with General Electric
CF6-50 engines. The uncommanded deployment occurred following climb and
level-out at 17,000 feet. The flightcrew reported severe buffeting of the
airplane with yaw to the left and pitch down of about five degrees. The
"REV UNLOCK" light was illuminated prior to onset of the buffeting.
The flightcrew shut down the engine, dumped fuel, turned back to the departure
airport, and landed the airplane. No injuries were reported among passengers
or crew.
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- Uncommanded deployment of a thrust reverser with a dual
translating cowl requires a minimum of two failures: (1) the over pressure
shut-off valve (OPSOV) must let pressure enter into the thrust reverser
actuation system; and (2) the directional pilot valve (DPV) must command
this pressure in the deploy direction. The cause of the presence of pressure
in the thrust reverser system has not been determined.
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- Results of a subsequent investigation by the engine manufacturer
revealed that the DPV was misassembled during overhaul by the DPV manufacturer
in 1997. The DPV was installed on the incident airplane in 1999. The misassembly
involved incorrect installation of a washer and bushing in the DPV piston/poppet
assembly. Results of vibration-table testing showed that a DPV misassembled
in this way could change positions from "stow command" to "deploy
command" on its own. When a DPV is in the "deploy command"
position, a single failure of the OPSOV could result in an uncommanded
deployment of the thrust reverser during flight. This condition, if not
corrected, could result in reduced controllability of the airplane.
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- Model A300 B2 and B4 series airplanes equipped with General
Electric CF6-50 engines have the same nacelle and thrust reverser system
as the airplane on which the event described previously occurred. Since
a misassembled DPV may be installed on Model A300 B2 and B4 series airplanes,
those airplanes may be subject to the unsafe condition identified in this
AD.
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- Explanation of Relevant Service Information
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- Airbus has issued All Operators Telex (AOT) A300/78A0023,
dated April 5, 2002, which describes procedures for deactivating both thrust
reversers on Model A300 B2 and B4 series airplanes. The DGAC classified
this service bulletin as mandatory and issued French telegraphic airworthiness
directive 2001-523(B), dated April 5, 2002, to ensure the continued airworthiness
of these airplanes in France.
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- FAA's Conclusions
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- This airplane model is manufactured in France and is
type certificated for operation in the United States under the provisions
of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and
the applicable bilateral airworthiness agreement. Pursuant to this bilateral
airworthiness agreement, the DGAC has kept the FAA informed of the situation
described above as it pertains to Airbus Model A300 B2 and B4 series airplanes.
The FAA has examined the findings of the DGAC, reviewed all available information,
and determined that AD action is necessary for products of this type design
that are certificated for operation in the United States.
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- Explanation of the Requirements of the Rule
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- Since an unsafe condition has been identified that is
likely to exist or develop on other airplanes of this same type design
registered in the United States, this airworthiness directive is issued
to require deactivating both thrust reversers in accordance with the AOT
described previously. Additionally, this airworthiness directive requires
revising the FAA-approved airplane flight manual (AFM) to require performance
penalties during certain takeoff conditions to ensure that safe and appropriate
performance is achieved for airplanes on which both thrust reversers have
been deactivated. On an interim basis, this AD includes a penalty of five
percent of the acceleration-stop distance for takeoffs on wet or contaminated
runways. This penalty is an estimate that is necessary to provide an acceptable
level of safety until we receive more information and a more precise performance
penalty can be established.
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- Similar AD Action on Other Airplanes
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- As stated previously, the incident described previously
occurred on a McDonnell Douglas Model DC-10-30 airplane equipped with General
Electric CF6-50 engines. The FAA is planning to issue an airworthiness
directive similar to this one, to require revising the AFM and deactivating
the thrust reversers under certain conditions on those airplanes. Because
the identified unsafe condition may be especially critical for Airbus Model
A300 B2 and B4 series airplanes, the FAA finds it appropriate to proceed
with this action applying to those airplanes now.
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- Interim Action
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- This is considered to be interim action until final action
is identified, at which time the FAA may consider further rulemaking.
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- Determination of Rule's Effective Date
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- Since a situation exists that requires the immediate
adoption of this regulation, it is found that notice and opportunity for
prior public comment hereon are impracticable, and that good cause exists
for making this AD effective in less than 30 days.
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- This rule is issued under 49 U.S.C. Section 44701 (formerly
section 601 of the Federal Aviation Act of 1958) pursuant to the authority
delegated to me by the Administrator, and is effective immediately upon
receipt of this AD.
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- 2002-08-51 AIRBUS: Docket No. 2002-NM-107-AD.
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- Applicability: Model A300 B2 and B4 series airplanes
equipped with General Electric CF6-50 engines, certificated in any category.
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- NOTE 1: Airbus Model A300 B4-600 series airplanes (commonly
referred to as "A300-600 series airplanes") are not affected
by this AD.
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- NOTE 2: This AD applies to each airplane identified in
the preceding applicability provision, regardless of whether it has been
modified, altered, or repaired in the area subject to the requirements
of this AD. For airplanes that have been modified, altered, or repaired
so that the performance of the requirements of this AD is affected, the
owner/operator must request approval for an alternative method of compliance
in accordance with paragraph (b) of this AD. The request should include
an assessment of the effect of the modification, alteration, or repair
on the unsafe condition addressed by this AD; and, if the unsafe condition
has not been eliminated, the request should include specific proposed actions
to address it.
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- Compliance: Required as indicated, unless accomplished
previously.
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- To prevent uncommanded in-flight deployment of the thrust
reverser, accomplish the following:
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- (a) Within 72 clock hours after receipt of this AD, accomplish
paragraphs (a)(1) and (a)(2) of this AD.
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- (1) Deactivate both thrust reversers according to Airbus
All Operators Telex (AOT) A300/78A0023, dated April 5, 2002.
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- (2) Revise the Limitations Section of the Airplane Flight
Manual (AFM) to include the following (this may be accomplished by inserting
a copy of this AD into the AFM):
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- "When the runway is wet or contaminated, reduce
by five percent the corrected acceleration-stop distance resulting from
the airplane flight manual takeoff performance analysis.
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- (Note: This supersedes any relief provided by the Master
Minimum Equipment List (MMEL).)"
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- Alternative Methods of Compliance
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- (b) An alternative method of compliance or adjustment
of the compliance time that provides an acceptable level of safety may
be used if approved by the Manager, International Branch, ANM-116, FAA,
Transport Airplane Directorate. Operators shall submit their requests through
an appropriate FAA Principal Maintenance or Operations Inspector, as applicable,
who may add comments and then send it to the Manager, International Branch,
ANM-116.
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- NOTE 3: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be obtained
from the International Branch, ANM-116.
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- Special Flight Permits
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- (c) Special flight permits may be issued in accordance
with sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the airplane to a location where the
requirements of this AD can be accomplished.
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- NOTE 4: The subject of this AD is addressed in French
telegraphic airworthiness directive 2001-523(B), dated April 5, 2002.
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- (d) AD 2002-08-51, issued on April 8, 2002, becomes effective
upon receipt.
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- For further information contact: Tim Backman, Aerospace
Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate,
1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2797;
fax (425) 227-1149.
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- Issued in Renton, Washington, on April 8, 2002.
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- Original Signed By Vi Lipski, Manager,
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- Transport Airplane Directorate,
- Aircraft Certification Service.
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