Airworthiness Directives; Fokker Model F27 Series Airplanes (Excluding Mark 050 Series Airplanes)

DEPARTMENT OF TRANSPORTATION

14 CFR Part 39

[Docket No. 93-NM-229-AD]

Airworthiness Directives; Fokker Model F27 Series Airplanes

(Excluding Mark 050 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 F27 series

airplanes. This proposal would require accomplishment of certain

structural modifications. This proposal is prompted by reports of

incidents involving fatigue cracking and corrosion in transport

category airplanes that are approaching or have exceeded their economic

design goal. These incidents have jeopardized the airworthiness of the

affected airplanes. The actions specified by the proposed AD are

intended to prevent degradation in the structural capabilities of the

affected airplanes. This action also reflects the FAA's decision that

long term continued operational safety should be assured by actual

modification of the airframe rather than repetitive inspections.

DATES: Comments must be received by May 9, 1994.

ADDRESSES: Submit comments in triplicate to the Federal Aviation

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

Attention: Rules Docket No. 93-NM-229-AD, 1601 Lind Avenue, SW.,

Renton, Washington 98055-4056. Comments may be inspected at this

location between 9 a.m. and 3 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-229-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-229-AD, 1601 Lind Avenue, SW., Renton, Washington

98055-4056.

Discussion

In April 1988, a transport category airplane managed to land after

tiny cracks in rivet holes in the upper fuselage linked together,

causing structural failure and explosive decompression. An 18-foot

section ripped from the fuselage. This accident focused greater

attention on the problem of aging aircraft.

In June 1988, the FAA sponsored a conference on aging airplane

issues, which was attended by representatives of the aviation industry

from around the world. It became obvious that, because of the

tremendous increase in air travel, the relatively slow pace of new

airplane production, and the apparent economic feasibility of operating

older technology airplanes rather than retiring them, increased

attention needed to be focused on this aging fleet and maintaining its

continued operational safety.

The FAA, in concert with the Regional Airline Association (RAA);

the General Aviation Manufacturers Association (GAMA); several U.S. and

non-U.S. operators of the affected airplanes; the Rijksluchtvaartdienst

(RLD), which is the airworthiness authority for the Netherlands; and

Fokker; has agreed to undertake the task of identifying and

implementing procedures to ensure continuing structural airworthiness

of aging commuter-class airplanes. This group reviewed selected service

bulletins, applicable to Fokker Model F27 series airplanes, to be

recommended for mandatory rulemaking action to ensure the continued

operational safety of these airplanes.

This group's proposal is contained in Fokker Report Number SE-278,

``F27 Aging Aircraft Project-Final Document,'' Issue 3, dated February

1, 1993. This Report references modifications from eight service

bulletins and recommends that they be incorporated in the applicable

Fokker Model F27 series airplanes. The modifications consist of three

modifications to the fuselage, two modifications to the wing, and three

modifications to the empennage of the airplane. They include structural

reinforcement of frames, ribs, and stringers; replacement of formers

and ribs; and installation of inspection doors and covers, access

holes, and drain holes.

The procedures described in these service bulletins are intended to

positively address conditions identified in Model F27 series airplanes

that, if not corrected, could result in structural failure.

The RLD classified this Report as mandatory and issued Netherlands

Airworthiness Directive (BLA) 91-058/5 (A), dated July 16, 1993, in

order to assure the continued airworthiness of these airplanes in the

Netherlands.

This airplane model is manufactured in the Netherlands and is type

certificated for operation in the United States under the provisions of

Sec. 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 fatigue cracking and corrosion are likely to exist or develop

on other airplanes of the same type design registered in the United

States, the proposed AD would require modification of Fokker Model F27

series airplanes prior to their economic design goal in accordance with

the Fokker Report described previously.

The economic design goal of an airplane is typically considered to

be the period of service after which a substantial increase in the

maintenance costs is expected to take place in order to assure

continued operational safety. The economic design goal for Fokker Model

F27 series airplanes is 90,000 landings for structural problems

associated with fatigue damage.

The proposed compliance time for implementation of the mandatory

structural modification program is prior to reaching the applicable

economic design goal. This time interval was determined based upon the

ability of the manufacturer to provide the parts necessary for the

modification, and the time necessary to incorporate the modifications.

In the interim, safety will be provided by various means currently

in place that are considered satisfactory to detect damage prior to the

occurrence of an unsafe condition. These include operators' on-going

basic maintenance programs; continuing inspections required by numerous

previously issued AD's; the Structural Integrity Program (SIP) program,

previously mandated by AD 92-19-07, Amendment 39-8365 (57 FR 42693,

September 16, 1992); the FAA's increased emphasis on surveillance of

operators' maintenance programs and procedures; and the FAA's

participation in programs to physically inspect high-time airplanes

during scheduled heavy maintenance.

The FAA estimates that 58 Fokker Model F27 series airplanes

(excluding Mark 050 series airplanes) of U.S. registry would be

affected by this proposed AD within the initial threshold. Since not

all affected airplanes would be required to accomplish every

modification referenced in each of the service bulletins, the cost

impact of the proposed modifications is estimated in the following

table. This cost includes the price of modification kits, and the

estimated labor rate is $55 per work hour. It does not include the cost

of downtime, planning, set up, familiarization, or tool acquisition.

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No. of Total cost for

Service Bulletin No. affected No. of work Cost of parts Cost per affected

airplanes hours per airplane airplane airplanes

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55-33 (B-77).................... 5 40 $314 $2,514.00 $12,570.00

55-12 (B-67).................... 5 20 121 1,221.00 6,105.00

55-12 (Part II)................. 5 30 168 1,818.00 9,090.00

55-61 Revision 2................ 13 45 2,235 4,710.00 61,230.00

57-68 Revision 1................ 58 556 1,279 31,859.00 1,847,822.00

53-19 (B-45) Issue 3............ 5 22 0 1,210.00 6,050.00

53-58 (B-149)................... 5 16 0 880.00 4,400.00

53-76 (B-211)................... 13 0.25 0 13.75 178.75

57-7 Issue 1.................... 5 32 400 2,160.00 10,800.00

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Based on these figures, above, the total cost impact of the

proposed AD on U.S. operators is estimated to be $1,958,245.75.

The total cost impact figure discussed above is based on

assumptions that no operator has yet accomplished any of the proposed

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

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

The FAA recognizes that the proposed modifications would require a

large number of work hours to accomplish. However, the threshold

specified in each of the service bulletins referenced by the Fokker

Report should allow ample time for the accomplishment of the

modifications coincidentally with scheduled major airplane inspection

and maintenance activities, thereby minimizing the costs associated

with special airplane scheduling.

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-229-AD.

Applicability: Model F27 series airplanes (excluding Mark 050

series airplanes), as listed in Fokker Report Number SE-278, ``F27

Aging Aircraft Project--Final Document,'' Issue 3, dated February 1,

1993; certificated in any category.

Compliance: Required as indicated, unless accomplished

previously.

To prevent structural failure, accomplish the following:

(a) Prior to reaching the incorporation thresholds listed in

Part II of Fokker Report Number SE-278, ``F27 Aging Aircraft

Project--Final Document,'' Issue 3, dated February 1, 1993,

accomplish the structural modifications listed in Part II of the

Fokker Report.

Note 1: The modifications required by this paragraph do not

terminate the inspection requirements of any other AD unless that AD

specifies that any such modification constitutes terminating action

for that inspection requirement.

(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, 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 2: Information concerning the existence of approved

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

obtained from the Standardization Branch, ANM-113.

(c) 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 8, 1994.

Darrell M. Pederson,

Acting Manager, Transport Airplane Directorate, Aircraft Certification

Service.

[FR Doc. 94-5852 Filed 3-11-94; 8:45 am]

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