AD 61-05-04

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AD Number:
61-05-04
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
Airworthiness Directives; Hiller Models UH-12D and UH-12E Helicopters
Subject:
Main Transmission
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
06/04/1974
Make:
Hiller Aviation | Siam Hiller Holdings, Inc.
Model:
UH-12D | UH-12E
Product Type:
Aircraft
Product Subtype:
Rotorcraft
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 61-05-04
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-1863

AD NUMBER:   61-05-04

SUBJECT HEADING:   Airworthiness Directives; Hiller Models UH-12D and UH-12E Helicopters

ACTION:  

SUMMARY:  

DATES:   Effective June 4, 1974.

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
61-05-04 HILLER: Amendment 507-261, as amended, is further amended by Amendment 39-1863. Applies to Hiller Model UH-12D and UH-12E helicopters certificated in all categories.

Compliance required as indicated unless previously accomplished.

To minimize failures of the main transmission:

(a) Prior to next flight:

(1) Inspect the planet spur gear, bevel ring gear and tail rotor bevel gear shaft for part number and heat treat lot number.

NOTE: The heat treat lot number, if any, is etched on the parts. The 1962 series parts do not bear heat treat lot numbers.

(2) Remove any planet spur gear, Part No. 23527, that does not have one of the following lot numbers:

(i) For Model UH-12D only - 35, 59, 71, 125, 171, 180, 181, 182, 185, 186, 196, 217, 245, 275, 309 and subsequent prefaced by "VHI", or any number prefaced by "HA".

(ii) For Model UH-12E only - 180, 185, 186, 196, 275, 309 and subsequent prefaced by "VHI", or any number prefaced by "HA".

(3) Replace with planet spur gears Part No. 1962C171 or 23527-3, or with Part No. 23527 having one of the above heat treat lot numbers specified in subparagraph (a)(2) above.

NOTE: Part No. 23527-3 gears must not be intermixed with Part No. 1962C171 or Part No. 23527 gears in the same transmission.

(4) Remove any bevel ring gear, Part No. 23528, that does not have one of the following lot numbers - 40, 40R, 277, 279, 286, 288, 293, 293A, 295, 309 and subsequent prefaced by "VHI", or any number prefaced by "HA".

(5) Replace with bevel ring gear Part No. 1962D58, 23528-5 or 23633, or with Part No. 23528 having one of the heat treat lot numbers specified in subparagraph (a)(4) above.

(6) Remove any tail rotor bevel gear shaft, Part No. 23522, that does not have one of the following lot numbers - 291, 292, 309 and subsequent prefaced by "VHI", or any number prefaced by "HA".

(7) Replace with tail rotor bevel gear shaft Part No. 23634-3 or 1962D65.

NOTE: Airworthiness Directive 64-11-02 applicable to Model UH-12E helicopters further requires the replacement of all tail rotor bevel gear shafts Part Nos. 23522 and 23634 with Part No. 23634-3 within the time period specified in that AD.

(8) For any bevel ring gear not replaced in accordance with subparagraph (5) above and any tail rotor bevel gear shaft not replaced in accordance with subparagraph (7) above or AD 64-11-02, inspect for proper gear tooth pattern.

NOTE: Refer to earlier transmission overhaul manual for description of acceptable pattern.

(9) Replace any bevel ring and tail rotor bevel gear shaft found to have improper gear tooth pattern in accordance with subparagraphs (5) and (7) above.

(b) For all Model UH-12D and UH-12E, Serial Numbers 942, 954, and 2001 through 2198, inclusive, accomplish the following prior to next flight and thereafter at intervals not to exceed 25 hours' time in service from the last inspection until modified in accordance with paragraph (d) of Airworthiness Directive 62-06-03:

(1) Remove and check the oil nozzle orifice, P/N 23607, located at lower right-hand side of main transmission for obstruction. If this nozzle is obstructed, inspect the Borg Warner clutch for evidence of lack of lubrication. If such evidence is found, replace the clutch with a serviceable clutch of the same or FAA-approved equivalent Part Number.

(2) Using a piece of 0.020-inch wire, check for obstruction in oil orifices located at forward topside of upper case, forward side of tachometer drive cover, and (if generator is installed on transmission) upper outboard side of generator drive housing. If any of these orifices are found obstructed, inspect the first stage planetary gear system for abnormal wear or overheating. If signs of such wear and/or overheating are noticed, overhaul or replace the first stage planetary system with a serviceable first stage planetary system of the same or FAA-approved equivalent Part Number.

(c) For all Model UH-12D and UH-12E Serial Nos. 942, 954 and 2001 through 2198 inclusive, accomplish the following prior to next flight and thereafter at intervals not to exceed 10 hours' (Model UH-12D) or 25 hours' (Model UH-12E) time in service from the last inspection until modified in accordance with paragraph (d) of Airworthiness Directive 62-06-03: Remove, disassemble, and inspect the engine oil filter and transmission oil filter for the presence of metallic particles. If aluminum, bronze, or steel particles are found in either or both of these filters, inspect the first stage planetary system for abnormal wear or overheating. If signs of such wear and/or overheating are noticed, overhaul or replace the first stage planetary system with a serviceable first stage planetary system of the same or FAA-approved equivalent Part Number.

(d) Within the next 150 hours' time in service, incorporate Part Nos. 23549-3 and 23549-5 bushings and Part No. 23578 planet gear shafts in the first stage planetary gear system of Model UH-12D helicopters with main transmission Part No. 23500, 23500-3 or 23500-7.

This directive Amendment 507-261 became effective upon publication in the Federal Register for all persons except those to whom it was made effective immediately by telegram dated February 21, 1961.

Revised May 9, 1961.

This amendment 39-1863 becomes effective June 4, 1974.

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