AD 2002-11-10

This amendment supersedes an existing airworthiness directive (AD) for Sikorsky Model S-70A and S-70C helicopters. That AD currently requires inspecting a certain part-numbered main landing gear drag beam (beam) for a crack, removing any cracked beam before further flight, and reducing the torque of the jackpad mounting bolt retention nut (nut) of each beam. This amendment contains the same actions but requires those actions for another beam part number (P/N). This amendment is prompted by the inadvertent omission in the current AD of the additional beam that is susceptible to failure due to stress corrosion resulting from sustained excessive tensile stress due to excessive torque of the nut. The actions specified by this AD are intended to prevent excessive torque of the nut, failure of a beam, and subsequent loss of control of the helicopter during takeoff or landing.

Final rule; request for comments.

2002-11-10 Sikorsky Aircraft Corporation: Amendment 39-12771. Docket No. 2002-SW-10-AD. Supersedes AD 2001-25-08, Amendment 39- 12561, Docket No. 2001-SW-18-AD.

Applicability: Model S-70A helicopters, serial numbers (S/N) 700029, 701129, 701322, 701325, 701327, 701329, 701331, 701333, 701592, 701593, 701594, 701595, 701613, 701614, 701825, 701835, 702127, and 702129, and Model S-70C helicopters, S/N 70583, 70785, 70788, 70792, 70793, 70794, 70797, 70798, 70799, 70800, 70811, 70812, 70813, 70830, 70831, 70836, 70837, 70848, 70855, 70856, 70867, 70868, 70879, 70884, 70892, 70910, 70918, 70927, 70928, 70929, 70949, 70950, 70951, 70954, 70957, 70958, 70959, 70965, 70966, and 701029, certificated in any category.

Note 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been otherwise modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters 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 within 30 hours time-in-service, unless accomplished previously.

To prevent excessive torque on a jackpad mounting bolt retention nut (nut), failure of a main landing gear drag beam (beam), and subsequent loss of control of the helicopter during takeoff or landing, accomplish the following:

(a) With jackpad installed, using a 10X or higher magnifying glass, visually inspect each beam, part number (P/N) 70250-12105 or 70250-32105, for a crack at a 3.0-inch radius around the upper and lower jackpad holes.

(1) If a crack is found, remove the beam.

(2) If a crack is suspected, dye-penetrant inspect the beam, and if a crack is found, remove the beam.

Note 2: Temporary Revision No. 19 of Sikorsky Aircraft Model S- 70 Maintenance Manual, dated January 23, 2001, pertains to the subject of this AD.

(b) If a crack is not found while accomplishing the requirements of paragraph (a) of this AD, retorque the nut, P/N MS21245-L12, on each beam as follows:

(1) Restrain the jackpad and rotate the nut counterclockwise to release the torque on the nut. If movement of the jackpad occurs, remove and replace the sealant from the lower surface of the jackpad/beam interface.
(2) Retorque the nut to 45-50 ft-lbs.
(3) Apply sealant to the nut and the immediate area.
(4) After sealant has dried, touch up the paint as required.
(5) After the paint has dried, apply a slippage mark (of a contrasting color) to the nut as follows:
(i) Wipe the areato be marked with a clean-lint-free cloth.
(ii) Apply F1000 Sentry Seal, or equivalent, with a width of approximately one half the diameter of the nut (to a maximum width of \3/16\ inch) and extending a minimum of \1/2\ inch on the base part (or to the edge of the part, whichever is smaller).

Note 3: Sikorsky Alert Service Bulletin No. 70-03-2, dated July 26, 1999, pertains to the subject of this AD.

(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, Boston Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Inspector, who may concur or comment and then send it to the Manager, Boston Aircraft Certification Office.

Note 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Boston Aircraft Certification Office.

(d) Special flightpermits may be issued in accordance with 14 CFR 21.197 and 21.199 to operate the helicopter to a location where the requirements of this AD can be accomplished.

(e) This amendment becomes effective on June 24, 2002.

On December 11, 2001, the FAA issued AD 2001-25-08, Amendment 39-12561 (66 FR 65102, December 18, 2001), to require certain inspections of each beam, P/N 70250-32105, for a crack, removing any cracked beam before further flight, and reducing the torque of the nut on each beam. That action was prompted by the failure of a beam due to stress corrosion resulting from sustained excessive tensile stress due to excessive torque on the nut. That condition, if not corrected, could result in excessive torque of the nut, failure of a beam, and subsequent loss of control of the helicopter during takeoff or landing.

Since the issuance of that AD, the FAA received a comment from the manufacturer stating that paragraph (a) of the AD should also apply to beam, P/N 70250-12105. The FAA agrees, and this superseding AD adds beam, P/N 70250-12105, to paragraph (a).

This unsafe condition is likely to exist or develop on other helicopters of these same type designs. Therefore, this AD supersedes AD 2001-25-08 to contain the same requirements but to add the beam, P/N 70250-12105, to paragraph (a) of this AD.

The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability and structural integrity of the helicopter. Therefore, within 30 hours time-in-service, the following actions are required, and this AD must be issued immediately:

Visually inspect each beam for a crack.
If a crack is found, remove the beam before further flight.
If a crack is suspected, dye-penetrant inspect the beam, and if a crack is found, remove the beam before further flight.
If no crack is found, reduce the torque on the nut.

Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable and that good cause exists for making this amendment effective in less than 30 days.

The FAA estimates that 3 helicopters currently type certificated in the United States (U.S.) will be affected by this AD, that it will take approximately 4 work hours to inspect the beam, to reduce the torque on each nut, and to replace a cracked beam. The average labor rate is $60 per work hour. Required parts will cost approximately $18,600 per beam. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $56,520, assuming you replace one beam on each U.S. helicopter and assuming that no other helicopter listed in the "applicability" will be type certificated in the U.S.

Comments Invited

Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.

Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rulemust submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 2002-SW-10-AD." The postcard will be date stamped and returned to the commenter.

The regulations adopted herein will 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 final rule does not have federalism implications under Executive Order 13132.

The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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, Safety.

Adoption of the Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.

Sec. 39.13 [Amended]

2. Section 39.13 is amended by removing Amendment 39-12561 (66 FR 65102, December 18, 2001), and by adding a new airworthiness directive (AD), Amendment 39-12771, to read as follows: