Airworthiness Directive · Amendment 39-15940 · Sikorsky Aircraft Corporation Model S-92A Helicopters
Sikorsky Aircraft Corporation Model S-92A Helicopters
Model S-92A helicopters, certificated in any category.
This amendment supersedes an existing airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. That AD currently requires removing all main gearbox (MGB) filter bowl assembly mounting titanium studs (titanium studs) and replacing them with steel studs. This amendment requires the same actions as the existing AD as well as changes to the Rotorcraft Flight Manual (RFM). This amendment is prompted by an accident, by recent RFM changes made by the manufacturer that were not available when we issued the existing AD, and by our determination that certain MGB Normal and Emergency procedures in the RFM are unclear, may cause confusion, and may mislead the crew regarding MGB malfunctions, in particular the urgency to land immediately after warning indications of loss of MGB oil pressure and oil pressure below 5 pounds per square inch (psi). Replacing the titanium studs is intended to prevent their failure, which could result in rapid loss of oil, failure of the MGB, and subsequent loss of control of the helicopter. Changing the RFM procedures is intended to clarify and emphasize certain Normal and Emergency procedures to give the crew the best available information in the event of certain MGB malfunctions.
To prevent failure of a main gearbox (MGB) filter bowl assembly mounting titanium stud (titanium stud), which could result in rapid loss of oil, failure of the MGB, and subsequent loss of control of the helicopter; and to clarify and emphasize certain Normal and Emergency procedures to give the crew the best available information in the event of certain MGB malfunctions, accomplish the following:
(a) Before further flight, for all Model S-92A helicopters with a MGB housing assembly, part number (P/N) 92351-15110-042, -043, or -044, that is not marked with “TS-062-01” near the P/N:
(1) Remove the titanium studs by following the Accomplishment Instructions in Sikorsky Alert Service Bulletin No. 92-63-014, Rev. A, dated March 20, 2009 (ASB), paragraph 3.A.
Note 1: Figure 1 of the ASB contains guidance for removal and installation of the studs
(2) Visually inspect the tapped holes and the MGB housing lockring counterbore for damage. If you find damage in the tapped holes or in the MGB housing lockring counterbore, contact the Boston Aircraft Certification Office for an approved repair.
(3) Install steel studs and mark the MGB housing as “TS-062-01” near the P/N by following the Accomplishment Instructions in the ASB, paragraph 3.C.
(b) Within 10 hours time-in-service, for all helicopters regardless of MGB housing assembly P/N:
(1) Revise the Normal and Emergency procedures sections of the Rotorcraft Flight Manual (RFM) by making the following changes, approved May 13, 2009:
| RFM | Remove | Remove | Insert |
|---|---|---|---|
| SA S92A-RFM-000 Part I | Temporary Revision (T-Rev) No. 1, Revised Main Gearbox Emergency Procedure | Page 2-12, and Sub-Section 7 “Gear Box Malfunctions” from Section III | Page 2-12, and Sub-Section 7 “Gear Box Malfunctions” from Section III of SA S92A-RFM-000, Revision No. 4. |
| SA S92A-RFM-002 Part I | T-Rev No. 5, Revised Main Gearbox Emergency Procedure | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III of SA S92A-RFM-002, Revision No. 10. |
| SA S92A-RFM-003 Part I | T-Rev No. 4, Revised Main Gearbox Emergency Procedure | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III of SA S92A-RFM-003, Revision No. 10. |
| SA S92A-RFM-004 Part I | T-Rev No. 4, Revised Main Gearbox Emergency Procedure | Page 2-12, and Sub-Section 7 “Gear Box Malfunctions” from Section III | Page 2-12, and Sub-Section 7 “Gear Box Malfunctions” from Section III of SA S92A-RFM-004, Revision No. 8. |
| SA S92A-RFM-005 Part I | T-Rev No. 3, Revised Main Gearbox Emergency Procedure | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III of SA S92A-RFM-005, Revision No. 7. |
| SA S92A-RFM-006 Part I | T-Rev No. 2, Revised Main Gearbox Emergency Procedure | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III | Page 2-13, and Sub-Section 7 “Gear Box Malfunctions” from Section III of SA S92A-RFM-006, Revision No. 8. |
| S92A-RFMS No. 3 | N/A | Sub-Section 7 “Gear Box Malfunctions” from Section III | Sub-Section 7 “Gear Box Malfunctions” from Section III of S92A-RFM Supplement No. 3, Revision No. 2. |
| All paragraphs of subsection 7 “Gear Box Malfunctions” starting with paragraph 7.0 are affected. |
Note 2: Inserting the following revisions, approved on May 13, 2009, and their associated Errata Sheets, dated June 4, 2009, into the RFM, as applicable, satisfies the requirements of this AD: (i) SA S92A-RFM-000 Revision No. 4, (ii) SA S92A-RFM-002 Revision No. 10, (iii) SA S92A-RFM-003 Revision No. 10, (iv) SA S92A-RFM-004 Revision No. 8, (v) SA S92A-RFM-005 Revision No. 7, (vi) SA S92A-RFM-006 Revision No. 8, and (vii) S92A-RFM Supplement No. 3, Revision No. 2.
(c) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Contact the Manager, Boston Aircraft Certification Office, FAA, Attn: John M. Coffey, FAA, 12 New England Executive Park, Burlington, MA 01803, telephone (781) 238-7173, fax (781) 238-7170, for information about previously approved alternative methods of compliance.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
