# AD 72-06-05 R2: Carburetors - Type: Airworthiness directive - Status: Current - Products: Marvel-Schebler Products Division Carburetors - Effective: July 3, 1986 - Superseded by: Nothing supersedes this AD - Product type: Appliance - Amendment: 39-5338 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A27CD5F612E9128586256A330055C532.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/72-06-05-R2 ## The airworthiness directive 72-06-05 R2 MARVEL SCHEBLER (Facet Aerospace Products Company): Amendment 39-1411 as amended by Amendment 39-1685 is further amended by Amendment 39-5338. Applies to Models MA-3, MA-3A, MA3-PA, MA-3SPA, MA4-SPA, MA4-5, MA4-5AA, MA-5, MA-5AA, MA-6AA and HA-6 carburetors used on various Franklin (Aircooled), Continental, Lycoming and Ranger engines, having one of Illustrations A, B, C, or D. Compliance is required within 30 days after the effective date of the AD, unless already accomplished. To present looseness or separation of the throttle arm, accomplish the following or any equivalent procedure approved by the Manager, New York Aircraft Certification Office, FAA, New England Region. (1) Inspect the throttle arm to verify that it is bottomed against the shoulder on the throttle stop and positioned so that full throttle travel is obtained, and if not, loosen clamping screw and reposition arm and/or re-rig control system in accordance with airplane manufacturers' maintenance instructions to obtain these conditions. (2) Inspect the throttle arm on Marvel Schebler MA-3, MA-3A, MA-3PA, MA3-SPA, and MA-4SPA carburetors to determine whether it has a spotfaced or milled flat for the head of the clamping screw. Replace any arm having a milled flat with one having a spotfaced flat. If not already installed, install a Marvel Schebler P/N A15-493 clamping screw (No. 10-24 x 5/8 slotted drilled fillister head) in the throttle arm. Torque the clamping screw to 20-28 in.-lb. and inspect the slot in the end of the arm for clearance. If the slot has closed so that no clearance remains, replace the arm and retorque to the above specifications. After the specified torque is established safety wire the throttle arm and clamping screw to the throttle stop as shown in Illustration A. (3) On Marvel Schebler MA-4-5, MA4-5AA, MA-5AA, MA-6AA, and HA-6 series carburetors with throttle arms having a 10-32 bolt and nut clamping the arm on the throttlestop, torque the nut to 35 to 40 in. lbs. and safety wire the throttle arm to the throttle stop as shown in Illustration B. On these series carburetors having a throttle arm threaded for a 10-24 screw, if not already installed, install a Marvel Schebler P/N A15-493 clamping screw (No. 10-24 x 5/8 slotted drilled fillister head) in the throttle arm and torque the screw to 20 to 28 in. lbs. Safety wire the throttle arm to the throttle stop as shown in Illustration C or D. NOTE: The procedures specified in American Aviation Corporation Service Letter No. 69-4, dated October 3, 1969, Cessna Service Letter SE71-17 revised February 25, 1972, and Lycoming Service Bulletin No. 330A, dated October 30, 1970, are approved as equivalent procedures to those prescribed in this AD for the applicable carburetors. Upon request, an equivalent means of compliance with the requirements of this AD may be approved by the Manager, New York Aircraft Certification Office, Aircraft Certification Division, New England Region, 181 South Franklin Avenue, Room 202, Valley Stream, New York 11581. Amendment 39-1411 (AD 72-6-5) became effective March 24, 1972. Amendment 39-1685 became effective July 9, 1973. This Amendment 39-5338 becomes effective July 3, 1986. ## Registered aircraft it may apply to (OpenAirDocs) No registered aircraft matched the models it names. Its text cites no advisory circulars or STCs. ## NTSB investigations that cite this AD (4) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB MIA01LA210](https://openairdocs.org/ntsb/MIA01LA210), Aug 7, 2001: Mooney M20C (N78933), Fort Lauderdale, FL, substantial damage. Probable cause: The failure of the mechanic who installed the carburetor after overhaul to safety the throttle linkage at the carburetor per an Airworthiness Directive resulting in separation of the throttle linkage… - [NTSB LAX00LA062](https://openairdocs.org/ntsb/LAX00LA062), Jan 2, 2000: Cessna 172A (N7249T), Dos Palos, CA, substantial damage. Probable cause: A partial loss of engine power due to the failure of maintenance personnel to properly install and safety the throttle arm to the carburetor throttle shaft. - [NTSB SEA97LA022](https://openairdocs.org/ntsb/SEA97LA022), Oct 29, 1996: Collier Q200 (N200CQ), Estacada, OR, substantial damage, 1 fatal. Probable cause: inadequate maintenance adjustment by the owner/pilot/mechanic, by not using safety wire to secure the throttle arm clamping screw, which resulted in a loose clamping screw and rotation of the… - [NTSB ANC93FA173](https://openairdocs.org/ntsb/ANC93FA173), Sep 11, 1993: Cessna 180 (N7541K), Cooper Landing, AK, substantial damage. Probable cause: THE SEPARATION OF THE THROTTLE ARM FROM THE THORTTLE SHAFT, THE FAILURE OF THE MAINTENANCE PERSONNEL TO COMPLY WITH THE AIRWORTHINESS DIRECTIVE, AND THE COMPANY MANAGEMENT'S FAILURE TO ADEQUATELY… --- From OpenAirDocs.org, an independent open copy of FAA and NTSB data. Only the Federal Register edition on govinfo.gov is the official legal text of an AD.