Federal Aviation Administration, DOT.
Notice of proposed rulemaking (NPRM).
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to Pratt Start Printed Page 26153& Whitney JT8D series turbofan engines. This proposal would require inspections of main fuel pump control shafts for excessive spline wear. Additionally, as terminating action to the inspections, this proposal would require the replacement of the main fuel pump control shaft with parts of improved design, and reworking the main fuel pump impeller, impeller gear train plate assembly, and impeller cover assembly. This proposal is prompted by reports of failed main fuel pump control shafts caused by excessive spline wear. The actions specified by the proposed AD are intended to prevent loss of engine throttle control, uncommanded acceleration, uncommanded deceleration or inflight shutdown, which could result in reduced airplane control during a critical phase of flight.
Comments must be received by July 5, 2000.
Submit comments to the Federal Aviation Administration (FAA), New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-29-AD, 12 New England Executive Park, Burlington, MA 01803-5299. Comments may also be sent via the Internet using the following address: “email@example.com”. Comments sent via the Internet must contain the docket number in the subject line. Comments may be inspected at this location between 8 a.m. and 4:30 p.m., Monday through Friday, except Federal holidays.
The service information referenced in the proposed rule may be obtained from Pratt & Whitney, 400 Main St., East Hartford, CT 06108; telephone 860-565-8770, fax 860-565-4503. This information may be examined at the FAA, New England Region, Office of the Regional Counsel, 12 New England Executive Park, Burlington, MA.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Christopher Spinney, Aerospace Engineer, Engine Certification Office, FAA, Engine and Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; telephone 781-238-7175, fax 781-238-7199.End Further Info End Preamble Start Supplemental Information
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 should identify the Rules Docket number and be submitted 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 99-NE-29-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, New England Region, Office of the Regional Counsel, Attention: Rules Docket No. 99-NE-29-AD, 12 New England Executive Park, Burlington, MA 01803-5299.
The Federal Aviation Administration (FAA) has received 51 reports of failed main fuel pump control shafts, which resulted in the loss of engine throttle control, uncommanded acceleration, uncommanded deceleration or inflight shutdown, on Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, and -15A turbofan engines. In one incident, a Boeing 737-200 powered by two PW Model JT8D-15 engines experienced an uncommanded acceleration of the No. 2 engine during takeoff roll. The exhaust gas temperature (EGT) overtemperature indication light illuminated in the cockpit at approximately 110 knots. A takeoff abort was attempted but the No. 2 engine did not respond to the throttle movement. The airplane went off the side of the runway, sustained landing gear damage, and was destroyed by fire after all passengers and crew escaped. Four passengers were injured during the evacuation. The investigation revealed a failed main fuel pump control shaft. The main fuel pump control shaft failure was attributed to wear of the main fuel pump control shaft spline. This condition, if not corrected, could result in the loss of engine throttle control, uncommanded acceleration, uncommanded deceleration or inflight shutdown, which could result in reduced aircraft control during a critical phase of flight.
The FAA has reviewed and approved the technical contents of PW Alert Service Bulletin (ASB) A6381 dated March 15, 2000, that describes procedures for inspecting the main fuel pump control shaft for excessive spline wear. As terminating action, PW ASB A6381 describes procedures for replacement of the main fuel pump control shaft with an improved wear resistant material shaft and reworking the main fuel pump impeller, impeller gear train plate assembly, and impeller cover assembly.
Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require inspecting main fuel pump control shafts for excessive wear, replacing the main fuel pump control shaft with parts of improved design, and reworking the main fuel pump impeller, impeller gear train plate assembly, and impeller cover assembly. The replacement and rework must be accomplished prior to accumulating 12,000 hours time-in-service (TIS) since last overhaul, or within 2,000 hours after the effective date of this AD, whichever occurs later. The actions would be required to be accomplished in accordance with the ASB described previously.
There are approximately 5,800 engines of the affected design in the worldwide fleet. The FAA estimates that 2962 engines installed on aircraft of US registry would be affected by this proposed AD, that it would take approximately 0.3 work hours to perform the required inspections and 0.5 hours per engine to accomplish the replacements proposed at overhaul, and that the average labor rate is $60 per work hour. Required parts would cost approximately $3,996 per engine. Based on these figures, the total cost impact of the proposed AD on US operators is estimated to be $11,978,328.
This proposal does not have federalism implications, as defined in Executive Order 13132, because it 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. Accordingly, the FAA has not consulted with state authorities prior to publication of this proposal. Start Printed Page 26154
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.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation 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:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. Section 39.13 is amended by adding the following new airworthiness directive:
Pratt & Whitney: Docket No. 99-NE-29-AD.
Applicability: Pratt & Whitney (PW) Models JT8D-1, -1A, -1B, -7, -7A, -7B, -9, -9A, -11, -15, -15A turbofan engines, installed on but not limited to Boeing 727 and 737 series, and McDonnell Douglas DC-9 series airplanes.
This airworthiness directive (AD) applies to each engine 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 engines 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 (e) 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 prevent loss of engine throttle control, uncommanded acceleration, uncommanded deceleration or inflight shutdown, which could result in reduced airplane control during a critical phase of flight, accomplish the following:
(a) At the next accessibility of the main fuel pump after accumulating 1,000 hours time in service (TIS) since last fuel pump overhaul, inspect, and replace, if necessary, the main fuel pump control shaft in accordance with procedures described in the Accomplishment Instructions of PW Alert Service Bulletin (ASB) A6381, dated March 15, 2000.
(b) Thereafter, reinspect the main fuel pump control shaft and remove and replace, if necessary, in accordance with intervals and procedures described in the Accomplishment Instructions of PW ASB A6381, dated March 15, 2000.
Installation and Terminating Action
(c) At the next main fuel pump overhaul, but prior to accumulating either 12,000 hours TIS since last fuel pump overhaul or 2,000 hours TIS after the effective date of this AD, whichever occurs later, install a reworked impeller, impeller gear train plate assembly and impeller cover assembly and a new main fuel pump control shaft in accordance with paragraph 2.A and 2.B. of PW ASB A6381, dated March 15, 2000. Installation of a reworked impeller, impeller gear train plate assembly and impeller cover assembly and a new main fuel pump control shaft in accordance with this paragraph constitute terminating action to the inspections required by paragraphs (a) and (b) of this AD.
(d) For the purpose of this AD:
(1) Accessibility of the main fuel pump is defined as removal of the fuel control from the fuel pump or removal of the fuel pump from the engine.
(2) Main fuel pump overhaul is defined as compliance with the manufacturer's recommended overhaul procedures described in Argo-Tech Overhaul Manual 73-11-1.
Alternative Methods of Compliance
(e) 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, Engine Certification Office (ECO). Operators shall submit their request through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, ECO.
Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the ECO.
(f) 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.
Issued in Burlington, Massachusetts, on May 1, 2000.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft Certification Service.
[FR Doc. 00-11303 Filed 5-4-00; 8:45 am]
BILLING CODE 4910-13-P