Airworthiness Directives; Lockheed Model L-1011 Series Airplanes Equipped With Rolls-Royce Model RB211-524 Series Engines

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-108-AD; Amendment 39-8817; AD 94-03-10]

Airworthiness Directives; Lockheed Model L-1011 Series Airplanes

Equipped With Rolls-Royce Model RB211-524 Series Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD),

applicable to certain Lockheed Model L-1011 series airplanes, that

requires modifying the engine high speed gearboxes. This amendment is

prompted by a fire in the engine high speed gearbox due to failure of a

roller bearing. The actions specified by this AD are intended to reduce

the possibility of fire in the engine high speed gearbox, and to ensure

that if a fire occurs, it is readily detected by the flight crew.

DATES: Effective March 14, 1994.

The incorporation by reference of certain publications listed in

the regulations is approved by the Director of the Federal Register as

of March 14, 1994.

ADDRESSES: The service information referenced in this AD may be

obtained from Lockheed Western Export Company, Dept. 693, Zone 0755, 86

South Cobb Drive, Marietta, Georgia 30063; or from Rolls-Royce PLC,

Technical Publications Department, P.O. Box 17, Parkside, Coventry,

England CV1 2LZ. This information may be examined at the Federal

Aviation Administration (FAA), Transport Airplane Directorate, Rules

Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Small

Airplane Directorate, Atlanta Aircraft Certification Office, suite

210C, 1669 Phoenix Parkway, Atlanta, Georgia; or at the Office of the

Federal Register, 800 North Capitol Street, NW., suite 700, Washington,

DC.

FOR FURTHER INFORMATION CONTACT: Thomas Peters, Aerospace Engineer,

Flight Test Branch, ACE-160A, FAA, Small Airplane Directorate, Atlanta

Aircraft Certification Office, suite 210C, 1669 Phoenix Parkway,

Atlanta, Georgia 30349; telephone (404) 991-3915; fax (404) 991-3606.

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

Aviation Regulations to include an airworthiness directive (AD) that is

applicable to Lockheed Model L-1011 series airplanes equipped with

Rolls-Royce Model RB211-524 series engines was published in the Federal

Register on September 29, 1993 (58 FR 50869). That action proposed to

require modifying the engine high speed gearboxes by installing an

additional fire detection system on the high speed gearboxes installed

on the number 1, 2, and 3 engines; installing a new vent tube in the

gear compartment of the high speed gearbox installed on the number 1,

2, and 3 engines; and modification of the high speed gearbox breather

duct installed on the number 2 engine.

Interested persons have been afforded an opportunity to participate

in the making of this amendment. Due consideration has been given to

the comments received.

One commenter supports the proposal.

Another commenter has no objection to the proposed rule, but

requests that the description of the addressed unsafe condition be

revised. This commenter points out that the preamble to the notice

indicated that the actions of the proposed rule are intended ``to

prevent a fire in the engine high speed gearbox.'' However, the

commenter contends that the actions will not prevent a fire from

occurring; they will only detect a fire after it has burned through the

gearbox. The FAA partially concurs with the commenter's request. While

it is true that the installation of the fire detection sensor does

nothing to prevent the initiation of a fire, the AD also requires the

installation of a new vent tube in the gear compartment of the high

speed gearbox in accordance with Rolls-Royce Service Bulletin RB.211-

72-4666, Revision 4, dated May 16, 1986. That service bulletin states,

in part, that ``in repositioning the vent air exit, the oil/air mixture

ratio is richened beyond the normal limits of combustion, therefore

reducing the possibility of internal fires should a failed bearing

overheat.'' In light of this, the FAA now considers that, although the

required actions of the rule will not prevent a fire, they will

contribute to reducing the possibility of fire in the engine high speed

gearbox. The description of the unsafe condition has been revised in

this final rule accordingly.

This commenter also points out that the wording in the preamble to

the notice indicated that failure of a roller bearing in the engine

high speed gearbox could cause a fire internal to the gearbox, ``which

could eventually breach the engine breather duct and potentially breach

the gearbox.'' However, a more accurate description of this situation

would be that ``failure of a roller bearing could cause a fire internal

to the gearbox, which could (1) eventually breach the flexible engine

breather duct within the engine cowls in the number 2 engine position,

and (2) also breach the high speed gearbox casing at any engine

position.'' The commenter states that the flexible engine breather duct

is installed only on the number 2 engine; the wording in the preamble

to the notice implies that each engine has both a gearbox and a

flexible duct. The FAA agrees with the commenter's suggested rewording

of this issue.

After careful review of the available data, including the comments

noted above, the FAA has determined that air safety and the public

interest require the adoption of the rule as proposed.

There are approximately 92 Model L-1011 series airplanes of the

affected design in the worldwide fleet. The FAA estimates that 24

airplanes of U.S. registry will be affected by this AD, that it will

take approximately 18 work hours per airplane to accomplish the

required actions, and that the average labor rate is $55 per work hour.

If the airplane is equipped with the Walter Kidde fire detection

system, required parts are estimated to cost $12,600 per airplane. If

the airplane is equipped with the Graviner fire detection system,

required parts are estimated to cost $18,600 per airplane. Based on

these figures, the total cost impact of the proposed AD on U.S.

operators is estimated to be between $326,160 and $470,160, or between

$13,590 and $19,590 per airplane.

The total cost impact figures discussed above are based on

assumptions that no operator has yet accomplished any of the

requirements of this AD action, and that no operator would accomplish

those actions in the future if this AD were not adopted. However, the

FAA has been advised that 19 airplanes of U.S. registry have been

modified with the breather duct that is required by this rule;

therefore, the future total cost impact of this AD on U.S. operators

will be less than the figures indicated above.

The regulations adopted herein will not have substantial direct

effects on the States, on the relationship between the national

government and the States, or on the distribution of power and

responsibilities among the various levels of government. Therefore, in

accordance with Executive Order 12612, it is determined that this final

rule does not have sufficient federalism implications to warrant the

preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this action (1) is

not a ``significant regulatory action'' under Executive Order 12866;

(2) is not a ``significant rule'' under DOT Regulatory Policies and

Procedures (44 FR 11034, February 26, 1979); and (3) will not have a

significant economic impact, positive or negative, on a substantial

number of small entities under the criteria of the Regulatory

Flexibility Act. A final evaluation has been prepared for this action

and it is contained in the Rules Docket. A copy of it may be obtained

from the Rules Docket at the location provided under the caption

ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Incorporation by

reference, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration amends 14 CFR part

39 of the Federal Aviation Regulations as follows:

PART 39--AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C.

106(g); and 14 CFR 11.89.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by adding the following new

airworthiness directive:

94-03-10 Lockheed: Amendment 39-8817. Docket 93-NM-108-AD.

Applicability: Model L-1011 series airplanes, equipped with

Rolls-Royce Model RB211-524 series engines; certificated in any

category.

Compliance: Required as indicated, unless accomplished

previously.

To reduce the possibility of a fire in the engine high speed

gearbox, and to ensure that if a fire occurs, it is readily detected

by the flight crew, accomplish the following:

(a) Within the next 16,000 flight hours after the effective date

of this AD, or within 48 months after the effective date of this AD,

whichever occurs first, accomplish paragraphs (a)(1), (a)(2), and

(a)(3) of this AD:

(1) Install an additional fire detection system on the high

speed gearbox on the number 1, number 2, and number 3 engines, in

accordance with Lockheed Service Bulletin 093-26-039, dated November

11, 1992.

(2) Install a new vent tube in the gear compartment of the high

speed gearbox on the number 1, number 2, and number 3 engines, in

accordance with Rolls-Royce Service Bulletin RB.211-72-4666,

Revision 4, dated May 16, 1986.

Note 1: Installation of a new vent tube in accordance with

Rolls-Royce Service Bulletin RB.211-72-4666, Revision 3, dated

October 14, 1977, prior to the effective date of this AD, is

considered acceptable for compliance with this AD.

(3) Modify the breather duct of the high speed gearbox on the

number 2 engine, in accordance with Lockheed Service Bulletin 093-

71-067, Revision 2, dated December 12, 1988.

Note 2: Modification of the breather duct in accordance with

Lockheed Service Bulletin 093-71-067, Revision 1, dated April 1,

1986, prior to the effective date of this AD, is considered

acceptable for compliance with this AD.

(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, Atlanta Aircraft Certification

Office (ACO), FAA, Small Airplane Directorate. Operators shall

submit their requests through an appropriate FAA Principal

Maintenance Inspector, who may add comments and then send it to the

Manager, Atlanta ACO.

Note 3: Information concerning the existence of approved

alternative methods of compliance with this AD, if any, may be

obtained from the Atlanta ACO.

(c) Special flight permits may be issued in accordance with FAR

21.197 and 21.199 to operate the airplane to a location where the

requirements of this AD can be accomplished.

(d) The actions shall be done in accordance with Lockheed

Service Bulletin 093-26-039, dated November 11, 1992; Lockheed

Service Bulletin 093-71-067, Revision 2, dated December 12, 1988;

and Rolls-Royce Service Bulletin RB.211-72-4666, Revision 4, dated

May 16, 1986, which contains the following list of effective pages:-

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Revision

Page No. level shown Date shown on page

on page

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1-4............................. 4 May 16, 1986.

4A, 5-6, 6A, 7-10............... 2 August 26, 1977.

Supplement:

1............................... 3 October 14, 1977.

2............................... 2 August 26, 1977.

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This incorporation by reference was approved by the Director of the

Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part

51. Copies may be obtained from Lockheed Western Export Company,

Dept. 693, Zone 0755, 86 South Cobb Drive, Marietta, Georgia 30063;

or from Rolls-Royce PLC, Technical Publications Department, P.O. Box

17, Parkside, Coventry, England CV1 2LZ. Copies may be inspected at

the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW.,

Renton, Washington; or at the FAA, Small Airplane Directorate,

Atlanta Aircraft Certification Office, suite 210C, 1669 Phoenix

Parkway, Atlanta, Georgia; or at the Office of the Federal Register,

800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on March 14, 1994.

Issued in Renton, Washington, on February 1, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-2659 Filed 2-10-94; 8:45 am]

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