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99-11-11: Main Gear Box Gear Shaft For Crack Inspection

FAA order 99-11-11 is an airworthiness directive in force since June 10, 1999. The FAA's subject line: Main Gear Box Gear Shaft For Crack Inspection. It names Airbus Helicopters AS-365: about 20 aircraft on the U.S. register today, though an order usually covers particular versions or serial numbers rather than every one. System: engine.

What it applies to as the FAA lists it

Kind of product
Aircraft
Makes
Airbus Helicopters
Models
AS-365N2, AS-365N3, SA-365N, SA-365N1, SA-366G1
On this site
Airbus Helicopters AS-365 20 registered

Dates and paperwork

In force since
June 10, 1999
Published
May 26, 1999
Docket
98-SW-47-AD
Replaces
97-15-15
Status
Current
The FAA's document
Read the order on the FAA's site

The FAA's summary their words, unchanged

This amendment supersedes an existing airworthiness directive (AD), applicable to Eurocopter France Model SA-365N, N1 and SA-366G1 helicopters, that currently requires repetitive inspections of the main gearbox (MGB) magnetic chip plug and oil filter if certain part number/modification level MGB's are installed. This new action expands the helicopter model and MGB applicability to include the SA-365N2 and N3 helicopters and all variants of the MGB. It also requires installing a MGB planetary gear shaft (gear shaft) vibration level monitoring unit (VLMU); inserting procedures into the Rotorcraft Flight Manual (RFM) for a preflight vibration check using the VLMU and inserting a related emergency procedure and limitation for an inoperative VLMU into the RFM. This action is prompted by two occurrences of gear shaft cracks. The actions specified by this AD are intended to detect cracks in the MGB planetary gear shaft, which could lead to failure of the MGB and subsequent lossof control of the helicopter.

The order itself the regulatory text, as published

Show the full text (4,745 characters)
99-11-11 EUROCOPTER FRANCE: Amendment 39-11182. Docket No. 98-SW-47-AD. Supersedes AD 97-15-15, Amendment 39-10313, Docket No. 97-SW-23-AD. Applicability: Model SA-365N, N1, N2, and N3 helicopters, serial numbers up to and including 6538, and SA-366G1 helicopters, 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 (d) 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 cracks in the main gearbox (MGB) planetary gear shaft (shaft), which could lead to failure of the MGB and subsequent loss of control of the helicopter, accomplish the following: (a) Within 25 hours time-in-service, install a MGB shaft vibration level monitoring unit (VLMU), in accordance with paragraph B. of the Accomplishment Instructions of either Eurocopter AS 365 Service Bulletin No. 31.00.03, applicable to Model SA-365N, N1, N2, and N3 helicopters; or Eurocopter SA 366 Service Bulletin No. 31.01, applicable to Model SA-366G1 helicopters, both dated June 23, 1998 (SB's). (b) Before further flight, accomplish the following: (1) Insert paragraphs 2D1), 2D2), and 2D3) of the SB's into the applicable Rotorcraft Flight Manual post-start normal procedures section. (2) Insert the following statement in the Emergency Procedures section of the applicable Rotorcraft Flight Manual: "If vertical vibrations at approximately 4/rev frequency are detected, reduce power, land as soon as practicable, and perform a VLMU vibration level check." (3) Insert the following statement into the Limitations section of the applicable Rotorcraft Flight Manual: "If the VLMU becomes inoperative, it must be returned to service within 30 calendar days or the helicopter must be grounded until such repairs are made." (c) If the VLMU becomes inoperative, inspect the MGB magnetic plug; it must be inspected before every flight and inspect the MGB oil filter each day in which flights are conducted or at intervals not to exceed 12 hours time-in-service, whichever occurs first. When metallic particles are found on either the magnetic plug or the oil filter element, conduct drive system ground vibration measurements before further flight. (d) An alternative method of compliance or adjustment of the compliance time thatprovides an acceptable level of safety may be used if approved by the Manager, Rotorcraft Standards Staff, Rotorcraft Directorate, FAA. Operators shall submit their requests through a FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Rotorcraft Standards Staff. NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Rotorcraft Standards Staff. (e) 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 helicopter to a location where the requirements of this AD can be accomplished. (f) The actions shall be done in accordance with the Eurocopter AS 365 Service Bulletin No. 31.00.03, or Eurocopter SA 366 Service Bulletin No. 31.01, both dated June 23, 1998, as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. NOTE 3: The subject of this AD is addressed in Direction Generale de L'Aviation Civile (France) AD 98-324-045(A), applicable to Model SA-365N helicopters, and AD 98-323-023(A), applicable to Model SA-366 helicopters, both dated August 12, 1998. (g) This amendment becomes effective on June 10, 1999.

Related safety bulletins advice on the same designs, not orders

2014-12-30SW-15-07 · Rotor Drive-Tail Rotor Drive Flange Shur-Lok Nut Inspection
2008-07-01SW-08-30R2 · Inadvertent Deployment of Crash Position Indicator (CPI) Beacon
2008-06-30SW-08-30R1 · Inadvertent Deployment of Crash Position Indicator (CPI) Beacon
2004-10-07SW-05-01 ·

Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of November 6, 2026. Connections as data: /graph/directive/99-11-11.json · aircraft systems.