AD DOCKET NUMBER: Docket No. FAA-2014-0335; Directorate Identifier 2013-SW-021-AD 

FAA EMPLOYEE CONTACTED: (Comments to AD docket) 

DATE AND TIME OF CONTACT: Thursday, August 7, 2014; 1000 

TYPE OF CONTACT: Phone call 

NAMES OF ALL PERSONS INVOLVED IN CONTACT, INCLUDING TITLES AND AFFILIATION: 

FAA participants: 

Jeff Lee, Aerospace Engineer, Boston ACO, ANE-150 

Industry participants: 

Phil Perschbacher, Principal Technical Engineer, Sikorsky Aircraft Corporation 

TOPIC DISCUSSED: 

Background: The purpose of the telecon was to provide the FAA with a better understanding of comments 

received regarding the compliance time and repair instruction revision level that was proposed in Notice of 

Proposed Rulemaking (NPRM) FAA-2014-0335, Dir. ID 2013-SW--021-AD. This NPRM was published 

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FAA discussion: 

Jeff Lee, FAA, asked if there is additional information to support the comment request indicating the 

compliance time is overly conservative at 1500 and with daily inspections, safety of aircraft can be 

maintained until next gearbox overhaul (at most 4125 hrs)? It was previously indicated that the gearbox is 

looked at the major inspection at 1500 hours and that has aircraft downtime. 

Industry discussion: 

Phil Perschbacher, Sikorsky, confirmed that there is a major inspection at 1500 hours. However, this does 

not require the removal of the gearbox. The gearbox is removed during the overhaul period at most 4125 

hours Performing the tasks ofORI 76350-065 can only be done with the gearbox removed from the 

aircraft. If done at the proposed 1500 hour time, it can be done but the gearbox would need to be removed 

and would be additional time and be burdensome. Performing the ORI or gearbox replacement during the 

gearbox overhaul reduced any operator impact as the gearbox is already removed for service. Also, there 

have been no additional reported incidents. The field experiences reported has been a gradual loss of oil 

and not an abrupt one. So the daily inspection is adequate to alert the operator to impending loss of repair 

integrity. That daily inspection will ensure safety until the gearbox is removed at the next overhaul period. 

This is why it was stated as being overly conservative. 

Mr. Lee asked Mr. Perschbacher to clarifY how the 4125 hours was determined and what is the maximum 

overhaul period for the Sikorsky S76 helicopter. 

Mr. Perschbacher indicated that the 4125 is based on the maximum overhaul time plus 10%. The gearbox 

overhaul times are 3250 or 3750 hours depending on model. So the maximum overhaul time is 3750 hours. 

Mr. Lee asked the comment regarding the ORI 76350-065 Rev F being overly conservative. 

Mr. Perschbacher indicated he would get back with more details and provide a revision summary and go 

through the changes at a later date. 
AD DOCKET NUMBER: Docket No. FAA-2014-0335; Directorate Identifier 2013-SW-021-AD 

FAA EMPLOYEE CONTACTED: (Comments to AD docket) 

DATE AND TIME OF CONTACT: Thursday, October 16, 2014; 1300 

TYPE OF CONTACT: Phone caJI 

NAMES OF ALL PERSONS INVOLVED IN CONTACT, INCLUDING TITLES AND AFFILIATION: 

FAA participants: 

Jeff Lee, Aerospace Engineer, Boston ACO, ANE-150 

Industry participants: 

Phil Perschbacher, Principal Technical Engineer, Sikorsky Aircraft Corporation 

TOPIC DISCUSSED: 

Background: The purpose of the telecon was to provide the FAA with a better understanding of comments 

received regarding the compliance time and repair instruction revision level that was proposed in Notice of 

Proposed Rulemaking (NPRM) FAA-2014-0335, Dir. lD 2013-SW-021-AD. This NPRM was published 

FAA discussion: 

Jeff Lee, FAA, asked if there is additional information to support the comment request indicating the use of 

ORI 76350-065 Rev F is overly conservative and that a revision change walkthrough would be made to 

show why the commented Rev B is sufficient. Previously, Sikorsky indicated that Rev F resolves the oil 

leakage issue. 

Industry discussion: 

Phil Perschbacher, Sikorsky, discusses the summary of each revision change for ORI 76350-065. It is 

indicated that Rev F would resolve the oil leakage issue, but so would Rev B. The revision F provides an 

additional pin retention change that would help prevent liner movement, but this is just a product 

improvement. A walkthrough of changes shows that the pin retention instructions are changed in ORI 

76350-065 rev B. Later revisions do not have any significant structural changes to any of the requirements 

in the pin retention instructions that affect the AD. The Revision B provided the diagram/figures and the 

depth of the insertion made clear that it was to engage the liner. This information was not in the prior 

revisions. The revision C or later changes do not show any significant change in the pin retention 

instructions first provided in Rev B. 

Mr. Lee asked if there have been any further reports and that aJI reports had repairs using ORI 76350-065 

Rev A or earlier. 

Mr. Perschbacher confirmed there were no further reports of any additional incidents and that aJI previous 

reports had repairs using ORI 76350-065 Rev A.