Airworthiness Directives; Fokker Model F28 Mark 1000, 2000, 3000, and 4000 Series Airplanes

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-205-AD]

Airworthiness Directives; Fokker Model F28 Mark 1000, 2000, 3000,

and 4000 Series Airplanes

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness

directive (AD) that is applicable to certain Fokker Model F28 Mark

1000, 2000, 3000, and 4000 series airplanes. This proposal would

require inspection to detect cracking in the area of the side stay

attachment lugs of the fitting subassembly of the main landing gear

(MLG), and replacement of cracked subassemblies with new or serviceable

subassemblies. This proposal is prompted by reports of cracking in the

subassembly of the MLG. The actions specified by the proposed AD are

intended to prevent damage to and/or failure of the support structure

of the MLG.

DATES: Comments must be received by May 31, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

Administration (FAA), Transport Airplane Directorate, ANM-103,

Attention: Rules Docket No. 93-NM-205-AD, 1601 Lind Avenue SW., Renton,

Washington 98055-4056. Comments may be inspected at this location

between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal

holidays.

The service information referenced in the proposed rule may be

obtained from Fokker Aircraft USA, Inc., 1199 North Fairfax Street,

Alexandria, Virginia 22314. This information may be examined at the

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

Washington.

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:

Comments Invited -

Interested persons are invited to participate in the making of the

proposed rule by submitting such written data, views, or arguments as

they may desire. Communications shall identify the Rules Docket number

and be submitted in triplicate to the address specified above. All

communications received on or before the closing date for comments,

specified above, will be considered before taking action on the

proposed rule. The proposals contained in this notice may be changed in

light of the comments received. -

Comments are specifically invited on the overall regulatory,

economic, environmental, and energy aspects of the proposed rule. All

comments submitted will be available, both before and after the closing

date for comments, in the Rules Docket for examination by interested

persons. A report summarizing each FAA-public contact concerned with

the substance of this proposal will be filed in the Rules Docket. -

Commenters wishing the FAA to acknowledge receipt of their comments

submitted in response to this notice must submit a self-addressed,

stamped postcard on which the following statement is made: ``Comments

to Docket Number 93-NM-205-AD.'' The postcard will be date stamped and

returned to the commenter.

Availability of NPRMs -

Any person may obtain a copy of this NPRM by submitting a request

to the FAA, Transport Airplane Directorate, ANM-103, Attention: Rules

Docket No. 93-NM-205-AD, 1601 Lind Avenue SW., Renton, Washington

98055-4056.

Discussion

The Rijksluchtvaartdienst (RLD), which is the airworthiness

authority for the Netherlands, recently notified the FAA that an unsafe

condition may exist on certain Fokker Model F28 Mark 1000, 2000, 3000,

and 4000 series airplanes that are equipped with certain Dowty

Aerospace main undercarriage units. The RLD advises that cracking has

been found in the fitting subassemblies of the main landing gear (MLG).

In three of these instances, the cracking had penetrated completely

through the fitting subassemblies from the side stay attachment lug to

the main bore, which resulted in loss of damping fluid. In another

incident, cracking was found in the web section that is adjacent to the

inner attachment bores of the side stay of the fitting subassembly of

the MLG. Investigation into the cause of this cracking revealed that

damage to the anodic film resulted in corrosion of these subassemblies.

Cracking in the fitting subassemblies of the MLG, if not corrected,

could result in damage to and/or failure of the support structure of

the MLG.

Fokker has issued Service Bulletin F28/32-149, dated August 30,

1991, that describes procedures for an eddy current inspection to

detect cracking in the area of the side stay attachment lugs of the

fitting subassembly of the MLG. The RLD classified this service

bulletin as mandatory and issued Netherlands Airworthiness Directive

(BLA) 91-080, Issue 2, dated February 21, 1992, in order to assure the

continued airworthiness of these airplanes in the Netherlands.

Additionally, Dowty Aerospace Gloucester, which is the manufacturer

of the main undercarriage units installed on these airplanes, has

issued Service Bulletin 32-161R, Revision 2, dated January 7, 1992,

that describes procedures for replacement of any cracked subassembly

with a new subassembly, or a serviceable subassembly that has been

identified previously with service bulletin number ``32-161R'' on its

nameplate. The Civil Aviation Authority (CAA), which is the

airworthiness authority for the United Kingdom, classified this service

bulletin as mandatory and issued CAA Airworthiness Directive 023-06-91

in order to assure the continued airworthiness of these aviation

products in the United Kingdom. The Fokker service bulletin references

this Dowty Aerospace Gloucester service bulletin.

This airplane model is manufactured in the Netherlands and is type

certificated for operation in the United States under the provisions of

Section 21.29 of the Federal Aviation Regulations and the applicable

bilateral airworthiness agreement. Pursuant to this bilateral

airworthiness agreement, the RLD has kept the FAA informed of the

situation described above. The FAA has examined the findings of the

RLD, 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.

Since an unsafe condition has been identified that is likely to

exist or develop on other airplanes of the same type design registered

in the United States, the proposed AD would require an eddy current

inspection to detect cracking in the area of the side stay attachment

lugs of the fitting subassembly of the MLG. The actions would be

required to be accomplished in accordance with the Fokker service

bulletin described previously.

This proposal would also require replacement of any cracked

fittings with new or serviceable fittings in accordance with the Dowty

Aerospace Gloucester service bulletin described previously.

The FAA estimates that 42 airplanes of U.S. registry would be

affected by this proposed AD, that it would take approximately 14 work

hours per airplane to accomplish the proposed actions, and that the

average labor rate is $55 per work hour. Based on these figures, the

total cost impact of the proposed AD on U.S. operators is estimated to

be $32,340, or $770 per airplane. This total cost figure assumes that

no operator has yet accomplished the proposed requirements of this AD

action.

The regulations proposed herein would 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

proposal would not have sufficient federalism implications to warrant

the preparation of a Federalism Assessment.

For the reasons discussed above, I certify that this proposed

regulation (1) is not a ``significant regulatory action'' under

Executive Order 12866; (2) is not a ``significant rule'' under the DOT

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

and (3) if promulgated, 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 copy of the draft

regulatory evaluation prepared for this action is contained in the

Rules Docket. A copy of it may be obtained by contacting the Rules

Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the

Administrator, the Federal Aviation Administration proposes to amend 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:

Fokker: Docket 93-NM-205-AD.

Applicability: Model F28 Mark 1000, 2000, 3000, and 4000 series

airplanes, serial numbers 11003 through 11241 inclusive, 11991, and

11992; certificated in any category, and equipped with any of the

following Dowty Aerospace Gloucester main undercarriage unit part

numbers:

200427003/004/005/006/007/008/009/010,

200633001/002/005/006,

200642001/002/003/004/005/006,

200739001/002/003/004,

200752001/002/003/004, or

200782001/002/003/004/005/006/007/008.

Compliance: Required as indicated, unless accomplished

previously. To prevent damage to and/or failure of the support

structure of the main landing gear (MLG), accomplish the following:

(a) Within 3 months after the effective date of this AD, perform

an eddy current inspection to detect cracking in the area of the

side stay attachment lugs of the fitting subassembly of the MLG in

accordance with Fokker Service Bulletin F28/32-149, dated August 30,

1991. If any cracked subassembly is found, prior to further flight,

replace with a new subassembly, or a serviceable subassembly that

has been identified previously with service bulletin number ``32-

161R'' on its nameplate; in accordance with Dowty Aerospace

Gloucester Service Bulletin 32-161R, Revision 2, dated January 7,

1992.

(b) As of the effective date of this AD, no person shall install

on any airplane a main undercarriage unit, having any of the

following Dowty Aerospace Gloucester part numbers, that has not been

identified previously with service bulletin number ``32-161R'' on

its nameplate:

200427003/004/005/006/007/008/009/010,

200633001/002/005/006,

200642001/002/003/004/005/006,

200739001/002/003/004,

200752001/002/003/004, or

200782001/002/003/004/005/006/007/008.

(c) 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, Standardization Branch, ANM-113,

FAA, Transport 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,

Standardization Branch, ANM-113.

Note: Information concerning the existence of approved

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

obtained from the Standardization Branch, ANM-113.

(d) Special flight permits may be issued in accordance with

Federal Aviation Regulations (FAR) 21.197 and 21.199 to operate the

airplane to a location where the requirements of this AD can be

accomplished.

Issued in Renton, Washington, on March 30, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-8053 Filed 4-4-94; 8:45 am]

BILLING CODE 4910-13-U