02-8284. Airworthiness Directives; Fokker Model F.28 Mark 0070 and 0100 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Fokker Model F.28 Mark 0070 and 0100 series airplanes. This proposal would require measurement of the over-center force of the thrust reverser operating levers; a functional test to verify proper energizing of the secondary lock solenoid of the thrust reversers; and corrective actions, if necessary. This action is necessary to detect and correct an insufficient over-center force in the corresponding thrust reverser operating lever, and incorrect setting of the thrust reverser selector switch (S9), which could result in uncommanded deployment of the thrust reversers during flight and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

DATES:

Comments must be received by May 6, 2002.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2001-NM-290-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. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 2001-NM-290-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Fokker Services B.V., P.O. Box 231, 2150 AE Nieuw-Vennep, the Netherlands. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

FOR FURTHER INFORMATION CONTACT:

Tom Rodriguez, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

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 action may be changed in light of the comments received.

Submit comments using the following format:

• Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
• For each issue, state what specific change to the proposed AD is being requested.
• Include justification (e.g., reasons or data) for each request.

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 action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2001-NM-290-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-114, Attention: Rules Docket No. 2001-NM-290-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Civil Aviation Authority—The Netherlands (CAA-NL), which is the airworthiness authority for the Netherlands, notified the FAA that an unsafe condition may exist on all Fokker Model F.28 Mark 0070 and 0100 series airplanes. The CAA-NL advises that an in-flight thrust reverser deployment occurred at the top of descent. The flightcrew encountered some buffeting, but no controllability problems. Forty-five seconds later, at a lower airspeed, the hydraulic pressure on the stow port of the thrust reverser actuator overpowered the aerodynamic forces on the deployed thrust reverser doors and closed them. Subsequent investigation revealed that the thrust reverser selector switch (S9), located in the left-hand thrust lever switchbox, was very critically adjusted. Additionally, the incident airplane had insufficient over-center force on the left-hand thrust reverser operating lever, and the corresponding “ground/flight” switch had remained unnoticed by the flightcrew in the “ground” position. Consequently, the addition of firm manual retardation of the thrust levers to IDLE resulted in a temporary, unintentional operation of the thrust reverser selector switch (S9).

Incorrect setting of the thrust reverser selector switch (S9) and an insufficient over-center force in the corresponding thrust reverser operating lever, if not corrected, could result in uncommanded deployment of one or both thrust reversers during flight and consequent reduced controllability of the airplane.

Explanation of Relevant Service Information

Fokker Services B.V. has issued Service Bulletin SBF100-76-015, dated January 15, 2001, including Manual Change Notification MCNM F100-060, dated January 1, 2001, which describes procedures for measurement of the over-center force of the left- and right-hand thrust reverser operating levers, and corrective actions, if necessary. The corrective actions include measuring and readjusting the minimum stop of the reverse-thrust lever and over-center force of the thrust reverser. The service bulletin also describes procedures for a functional test to verify proper energizing of the secondary lock solenoid of the left- and right-hand thrust reversers, and corrective actions, if necessary. The corrective actions include a rigging test of the thrust reverser switchbox, another functional test to verify proper energizing of the secondary lock solenoid, and replacement of the thrust reverser switchbox with a new or serviceable switchbox, if necessary. The CAA-NL classified this service bulletin as mandatory and issued Dutch airworthiness directive 2001-040, dated March 30, 2001, in order to assure the continued airworthiness of these airplanes in the Netherlands.

FAA's Conclusions

These airplane models are manufactured in the Netherlands and are 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 CAA-NL has kept the FAA informed of the situation described above. The FAA has examined the findings of the CAA-NL, 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.

Explanation of Requirements of Proposed Rule

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 accomplishment of the actions specified in the service bulletin described previously, except as discussed below.

Difference Between Proposed Rule and Service Bulletin

In lieu of performing corrective actions, the service bulletin allows a readjustment of the over-center force of the thrust reverser operating lever to be scheduled for the next scheduled hangar check or within 1,000 flight hours, whichever comes first. The FAA has determined that such rescheduling would not address the identified unsafe condition in a timely manner. In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the proposed corrective actions. In light of all of these factors, the FAA finds that the proposed corrective actions should be accomplished before further flight.

Interim Action

This is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking.

Cost Impact

The FAA estimates that 139 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 2 work hours per airplane to accomplish the proposed actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $16,680, or $120 per airplane.

The 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 proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.

Regulatory Impact

The regulations proposed herein would not have a substantial direct effect 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, it is determined that this proposal would not have federalism implications under Executive Order 13132.

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 part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39—AIRWORTHINESS DIRECTIVES

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

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

Fokker Services B.V.: Docket 2001-NM-290-AD.

Applicability: All Model F.28 Mark 0070 and 0100 series airplanes, certificated in any category.

Note 1:

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 (c) 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.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct incorrect an insufficient over-center force in the corresponding thrust reverser operating lever and incorrect setting of the thrust reverser selector switch (S9), which could result in uncommanded deployment of the thrust reversers during flight and consequent reduced controllability of the airplane, accomplish the following:

Over-Center Force Measurement and Readjustment

(a) Within 6 months after the effective date of this AD, measure the over-center force of the left- and right-hand thrust reverser operating levers, per paragraph 2.A. of the Accomplishment Instructions of Fokker Service Bulletin SBF100-76-015, dated January 15, 2001, including Manual Change Notification MCNM F100-060, dated January 1, 2001.

(1) If the over-center force is equal to or higher than 4.5 pounds, but not higher than 5.5 pounds, no further action is required by this paragraph.

(2) If the over-center force is less than 4.5 pounds or higher than 5.5 pounds, before further flight, readjust the over-center force and accomplish the corrective actions (including measuring and readjusting the minimum stop of the reverse-thrust lever and over-center force of the thrust reverser), per the service bulletin.

Functional Test and Corrective Actions

(b) Within 6 months after the effective date of this AD, perform a functional test to verify proper energizing of the secondary lock solenoid of the left- and right-hand thrust reversers, per paragraph 2.B. of the Accomplishment Instructions of Fokker Service Bulletin SBF100-76-015, dated January 15, 2001, including Manual Change Notification MCNM F100-060, dated January 1, 2001.

(1) If the secondary lock solenoid does NOT (momentarily or continuously) energize with movement of the thrust reverser operating lever as described in paragraph 2.B.(9) of the service bulletin, no further action is required by this paragraph.

(2) If the secondary lock solenoid (momentarily or continuously) energizes with movement of the thrust reverser operating lever as described in paragraph 2.B.(9) of the service bulletin, before further flight, perform a rigging test of the thrust reverser switchbox and repeat the functional test to verify proper energizing of the secondary lock solenoid one more time, per paragraph 2.B.(9) of the service bulletin.

(i) If the solenoid does NOT (momentarily or continuously) energize with movement of the thrust reverser operating lever as described in paragraph 2.B.(9) of the service bulletin, no further action is required by this paragraph.

(ii) If the secondary lock solenoid still (momentarily or continuously) energizes with movement of the thrust reverser operating lever as described in paragraph 2.B.(9) of the service bulletin, before further flight, replace the thrust reverser switchbox with a new or serviceable switchbox, per the service bulletin.

Alternative Methods of Compliance

(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, International Branch, ANM-116, Transport Airplane Directorate, FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

Note 2:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits

(d) 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.

Note 3:

The subject of this AD is addressed in Dutch airworthiness directive 2001-040, dated March 30, 2001.

Issued in Renton, Washington, on March 28, 2002.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.