AD 70-04-04

final rule

AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines

AD Number
70-04-04
Status
final_rule
Effective Date
Product Category
engine
Docket
Unknown
FR Citation
This information is not available.
Technical illustration of an aircraft turbine engine assembly
Problem area Engine

Applicability

TypeManufacturerModelDetails
engine Honeywell International Inc. TPE331-1 AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
engine Honeywell International Inc. TPE331-1U AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
engine Honeywell International Inc. TPE331-1UA AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
engine Honeywell International Inc. TPE331-2 AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
engine Honeywell International Inc. TPE331-2U AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
engine Honeywell International Inc. TPE331-2UA AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines

Unsafe Condition

Backing off of the high speed pinion retaining nut can cause a serious engine failure.

AI-generated summary from the source AD text. Verify against the official source before acting.

Required Actions

Within 10 hours time in service, inspect the engine oil filter for metal particles and install a placard advising pilots to shut down the engine if there is an abrupt loss of torque indication. At each inspection, replace the filter and return the removed filter for laboratory examination. Within 150 hours time in service, rework or replace the high speed pinion gear shaft assembly per AiResearch Service Bulletin 587.

AI-generated summary from the source AD text. Verify against the official source before acting.

Compliance Time

Within 10 hours time in service

AI-generated summary from the source AD text. Verify against the official source before acting.

Affected Aircraft

Honeywell International Inc. Model TPE331-1 and -2 engines with serial numbers: 90005, 90009, 90010, 90011, 90014, 90016, 90017, 90018, 90019, 90022, 90023, 90024, 90027, 90028, 90029, 90030, 91003, 91004, 91005, 91006, 91009, 91011, 91013 thru 91021, 91023, 91024, 91025, 91027, 92001, 92002, 92003, 92004, 92005, 92007, 92010, 92012, 92013, 92014, 92016 thru 92027, 93007, 93008, 93009, 93010.

AI-generated summary from the source AD text. Verify against the official source before acting.

Federal Register Abstract

High Speed Pinion Retaining Nut

Applicability Source Text

Show captured applicability text from the source AD
AD Final Rules - DRS_70-04-04.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
70-04-04
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
Subject:
High Speed Pinion Retaining Nut
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Honeywell International Inc.
Model:
TPE331-1 | TPE331-1U | TPE331-1UA | TPE331-2 | TPE331-2U | TPE331-2UA
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 70-04-04
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-944

AD NUMBER:   70-04-04

SUBJECT HEADING:   AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines


ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
70-04-04 AIRESEARCH: Amendment 39-944. Applies to Model TPE331-1 and -2 S/N engines: 90005, 90009, 90010, 90011, 90014, 90016, 90017, 90018, 90019, 90022, 90023, 90024, 90027, 90028, 90029, 90030, 91003, 91004, 91005, 91006, 91009, 91011, 91013 thru 91021, 91023, 91024, 91025, 91027, 92001, 92002, 92003, 92004, 92005, 92007, 92010, 92012, 92013, 92014, 92016, thru 92027, 93007, 93008, 93009, 93010; installed in but not limited to Mooney MU-2, Merlin 2B, Volpar Turboliner and Short Skyvan aircraft is effective upon receipt of this telegram. This directive necessary because of a serious engine failure caused by backing off of the high speed pinion retaining nut. To detect and prevent engine failure from this cause, the following is required:

(A) Within 10 hours time in service unless previously accomplished within the last 15 hours time in service, and at intervals not to exceed 25 hours time in service thereafter, remove the engine oil filter and inspect the filter for metal particles. If an abnormal quantity of metal particles is found, accomplish Item (C) before further operation of the engine. At each inspection a replacement filter must be installed and the filter which was removed shall be returned for laboratory examination to AiResearch or to a facility approved by the Chief, Aircraft Engineering Division, Western Region. Any finding of unacceptable metal contamination by AiResearch or other approved facility will be communicated to the owner or operator and the FAA. Upon receipt of such notice the engine shall then not be operated until Item (C) is accomplished. 25 hours oil filter special inspections may be discontinued upon completion of Item (C).

(B) Within 10 hours time in service, install a placard in full view of the pilot to read: 'If abrupt and complete loss of torque indication occurs, shut down the engine and determine the cause.' This placard may be removed when Item (C) is accomplished.

(C) Within 150 hours time in service unless previously accomplished, rework or replace the high speed pinion gear shaft assembly, P/N 869337-2, -3, or -4, in accordance with AiResearch Service Bulletin No. 587, dated 5 February 1970, or later FAA approved revisions.

This amendment is effective upon publication in the Federal Register for all person except those to whom it was made effective immediately by telegram dated February 5, 1970.


FOOTER:

Document Text

Show stored source text (verify against official source)
AD Final Rules - DRS_70-04-04.html
Copy URL
Print/Save as PDF
Document Versions
 Feedback
Details
AD Number:
70-04-04
Document Type:
AD Final Rules
Docket Number:
Unknown
Subject Heading:
AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines
Subject:
High Speed Pinion Retaining Nut
Status:
Current
Citation:
This information is not available.
Citation Publish Date:
Effective Date:
Make:
Honeywell International Inc.
Model:
TPE331-1 | TPE331-1U | TPE331-1UA | TPE331-2 | TPE331-2U | TPE331-2UA
Product Type:
Engine
Product Subtype:
Affected AD:
Superseded AD:
Affected By:
Superseded By:
Service/Office:
Office of Primary Responsibility:
CFR Part Reference:
Part 39
Comments:
AIRWORTHINESS DIRECTIVES FINAL RULES: 70-04-04
CITATION:   This information is not available.

PAGE NUMBER:  

DOCKET NUMBER:   Unknown

AMENDMENT:   39-944

AD NUMBER:   70-04-04

SUBJECT HEADING:   AIRESEARCH Model TPE-331-1 and TPE-331-2 Engines


ACTION:  

SUMMARY:  

DATES:  

ADDRESSES:  

FOR FURTHER INFORMATION CONTACT:  

SUPPLEMENTARY INFORMATION:  

REGULATORY TEXT:  
70-04-04 AIRESEARCH: Amendment 39-944. Applies to Model TPE331-1 and -2 S/N engines: 90005, 90009, 90010, 90011, 90014, 90016, 90017, 90018, 90019, 90022, 90023, 90024, 90027, 90028, 90029, 90030, 91003, 91004, 91005, 91006, 91009, 91011, 91013 thru 91021, 91023, 91024, 91025, 91027, 92001, 92002, 92003, 92004, 92005, 92007, 92010, 92012, 92013, 92014, 92016, thru 92027, 93007, 93008, 93009, 93010; installed in but not limited to Mooney MU-2, Merlin 2B, Volpar Turboliner and Short Skyvan aircraft is effective upon receipt of this telegram. This directive necessary because of a serious engine failure caused by backing off of the high speed pinion retaining nut. To detect and prevent engine failure from this cause, the following is required:

(A) Within 10 hours time in service unless previously accomplished within the last 15 hours time in service, and at intervals not to exceed 25 hours time in service thereafter, remove the engine oil filter and inspect the filter for metal particles. If an abnormal quantity of metal particles is found, accomplish Item (C) before further operation of the engine. At each inspection a replacement filter must be installed and the filter which was removed shall be returned for laboratory examination to AiResearch or to a facility approved by the Chief, Aircraft Engineering Division, Western Region. Any finding of unacceptable metal contamination by AiResearch or other approved facility will be communicated to the owner or operator and the FAA. Upon receipt of such notice the engine shall then not be operated until Item (C) is accomplished. 25 hours oil filter special inspections may be discontinued upon completion of Item (C).

(B) Within 10 hours time in service, install a placard in full view of the pilot to read: 'If abrupt and complete loss of torque indication occurs, shut down the engine and determine the cause.' This placard may be removed when Item (C) is accomplished.

(C) Within 150 hours time in service unless previously accomplished, rework or replace the high speed pinion gear shaft assembly, P/N 869337-2, -3, or -4, in accordance with AiResearch Service Bulletin No. 587, dated 5 February 1970, or later FAA approved revisions.

This amendment is effective upon publication in the Federal Register for all person except those to whom it was made effective immediately by telegram dated February 5, 1970.


FOOTER:

Source: Official FAA Source ↗

Retrieved: Apr 8, 2026

Rights: U.S. Government Public Domain

This site is not affiliated with or endorsed by the FAA. Always verify with official sources.