AD 88-25-09
final rule
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters | AS355E | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
| aircraft | Airbus Helicopters | AS355F | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
| aircraft | Airbus Helicopters | AS355F1 | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
| aircraft | Airbus Helicopters | AS355F2 | Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters |
Unsafe Condition
Tail rotor drive shaft failure, which could result in loss of control.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Perform vibration level measurements every 100 hours' time in service. If vibration exceeds 3 IPS, replace the shaft before further flight or inspect every 10 hours' time in service. If between 1.75 and 3 IPS, clean fan assembly, recheck vibration, balance fan if needed, and inspect splines and bearings. Replace shaft if vibration remains above 1.75 IPS.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within the next 50 hours' time in service after receipt of this AD, and thereafter at intervals not to exceed 100 hours' time in service.
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Affected Aircraft
AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE) Model AS 355 series helicopters with Part Number 355A34-1037-00 tail rotor drive shaft.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Tail Rotor Drive Shaft
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_88-25-09.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 88-25-09 Document Type: AD Final Rules Docket Number: 88-ASW-59 Subject Heading: Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 S...Show more Subject: Tail Rotor Drive Shaft Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 07/14/1989 Make: Airbus Helicopters Model: AS355E | AS355F | AS355F1 | AS355F2 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: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 88-25-09 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 88-ASW-59 AMENDMENT: 39-6237 AD NUMBER: 88-25-09 SUBJECT HEADING: Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters ACTION: SUMMARY: DATES: Effective July 14, 1989. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 88-25-09 AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Amendment 39-6237. Final copy of priority letter AD. (Docket No. 88- ASW-59) Applicability: All Aerospatiale Model AS 355 series helicopters containing Part Number (P/N) 355A34-1037-00, tail rotor drive shaft, certificated in any category. Compliance: Required as indicated, unless already accomplished. To prevent tail rotor drive shaft failure, which could result in the loss of control, accomplish the following: (a) Within the next 50 hours' time in service after receipt of this AD, and thereafter at intervals not to exceed 100 hours' time in service, perform the vibration level measurement with the aircraft on the ground and with the rotor turning, in accordance with Maintenance Work Card 65-10-00-604. (1) If the measured vibration level is equal to or above 3 inches per second (IPS)-- (i) Replace the tail rotor drive shaft with a serviceable part prior to further flight; or (ii) The tail rotor drive shaft may be operated for no more than an additional 50 hours' time in service provided the vibration level is reduced to 1.75 IPS or below, and no cracks are found by the following inspections. Before the next flight and thereafter at intervals not to exceed 10 hours' time in service, inspect the inside surface of the shaft in the area of the forward flange and splined fitting attachment (both ends of the shaft, adjacent to the Jo- bolts) for cracks. If cracks are found, replace the tail rotor drive shaft with an airworthy shaft prior to further flight. (2) If the measured vibration level is above 1.75 IPS, but less than 3 IPS: (i) Clean the fan assembly in accordance with Maintenance Work Card 12-00-00-306. (ii) Perform a new vibration level check. (iii) If the vibration level is less than 1.75 IPS after cleaning, no further action is required. (iv) If the vibration level is above 1.75 IPS, balance the fan assembly in accordance with Maintenance Work Card 65-10-00-604, and perform a new vibration level check. (A) If the vibration level is less then 1.75 IPS after balancing, no further action is required. (B) If the measured vibration level measures above 1.75 IPS, inspect the sliding flange splines for wear and the fan bearings for abnormal play in accordance with the applicable Maintenance Work Cards. Replace parts found outside specified limits and perform a new vibration check. If the vibration level remains above 1.75 IPS, replace the tail rotor drive shaft with a serviceable part prior to further flight. (3) If the measured vibration level is below 1.75 IPS, no further action is required. (b) Accomplish the vibration level measurement and shaft replacement, as necessary, in accordance with the instruction of paragraph (a) before and after the replacement of any fan assembly component or any tail rotor drive shaft. (c) Replace the tail rotor drive shaft in accordance with the instructions of paragraph (a)(1) if-- (1) The vibration level exceeded 3 IPS as measured during previous compliance with Aerospatiale Service Bulletin 05.20, before issuance of this AD; or (2) The tail rotor drive shaft was installed when the oil cooler fan was changed for foreign object damage or when the fan bearings were changed for bearing discrepancies. (d) An alternate method of compliance with the AD which provides an equivalent level of safety may be used if approved by the Manager, Rotorcraft Standards Staff, ASW-110, FAA, Fort Worth, Texas 76193-0110. This amendment (39-6237, AD 88-25-09) becomes effective on July 14, 1989, as to all persons except those persons to whom it was made immediately effective by priority letter AD No. 88-25-09, issued December 9, 1988, which contained this amendment. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_88-25-09.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 88-25-09 Document Type: AD Final Rules Docket Number: 88-ASW-59 Subject Heading: Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 S...Show more Subject: Tail Rotor Drive Shaft Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 07/14/1989 Make: Airbus Helicopters Model: AS355E | AS355F | AS355F1 | AS355F2 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: Updated RGL applicability to match AD applicability; CAR C-11-185 AIRWORTHINESS DIRECTIVES FINAL RULES: 88-25-09 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: 88-ASW-59 AMENDMENT: 39-6237 AD NUMBER: 88-25-09 SUBJECT HEADING: Airworthiness Directives; AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Model AS 355 Series Helicopters ACTION: SUMMARY: DATES: Effective July 14, 1989. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 88-25-09 AEROSPATIALE (SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE): Amendment 39-6237. Final copy of priority letter AD. (Docket No. 88- ASW-59) Applicability: All Aerospatiale Model AS 355 series helicopters containing Part Number (P/N) 355A34-1037-00, tail rotor drive shaft, certificated in any category. Compliance: Required as indicated, unless already accomplished. To prevent tail rotor drive shaft failure, which could result in the loss of control, accomplish the following: (a) Within the next 50 hours' time in service after receipt of this AD, and thereafter at intervals not to exceed 100 hours' time in service, perform the vibration level measurement with the aircraft on the ground and with the rotor turning, in accordance with Maintenance Work Card 65-10-00-604. (1) If the measured vibration level is equal to or above 3 inches per second (IPS)-- (i) Replace the tail rotor drive shaft with a serviceable part prior to further flight; or (ii) The tail rotor drive shaft may be operated for no more than an additional 50 hours' time in service provided the vibration level is reduced to 1.75 IPS or below, and no cracks are found by the following inspections. Before the next flight and thereafter at intervals not to exceed 10 hours' time in service, inspect the inside surface of the shaft in the area of the forward flange and splined fitting attachment (both ends of the shaft, adjacent to the Jo- bolts) for cracks. If cracks are found, replace the tail rotor drive shaft with an airworthy shaft prior to further flight. (2) If the measured vibration level is above 1.75 IPS, but less than 3 IPS: (i) Clean the fan assembly in accordance with Maintenance Work Card 12-00-00-306. (ii) Perform a new vibration level check. (iii) If the vibration level is less than 1.75 IPS after cleaning, no further action is required. (iv) If the vibration level is above 1.75 IPS, balance the fan assembly in accordance with Maintenance Work Card 65-10-00-604, and perform a new vibration level check. (A) If the vibration level is less then 1.75 IPS after balancing, no further action is required. (B) If the measured vibration level measures above 1.75 IPS, inspect the sliding flange splines for wear and the fan bearings for abnormal play in accordance with the applicable Maintenance Work Cards. Replace parts found outside specified limits and perform a new vibration check. If the vibration level remains above 1.75 IPS, replace the tail rotor drive shaft with a serviceable part prior to further flight. (3) If the measured vibration level is below 1.75 IPS, no further action is required. (b) Accomplish the vibration level measurement and shaft replacement, as necessary, in accordance with the instruction of paragraph (a) before and after the replacement of any fan assembly component or any tail rotor drive shaft. (c) Replace the tail rotor drive shaft in accordance with the instructions of paragraph (a)(1) if-- (1) The vibration level exceeded 3 IPS as measured during previous compliance with Aerospatiale Service Bulletin 05.20, before issuance of this AD; or (2) The tail rotor drive shaft was installed when the oil cooler fan was changed for foreign object damage or when the fan bearings were changed for bearing discrepancies. (d) An alternate method of compliance with the AD which provides an equivalent level of safety may be used if approved by the Manager, Rotorcraft Standards Staff, ASW-110, FAA, Fort Worth, Texas 76193-0110. This amendment (39-6237, AD 88-25-09) becomes effective on July 14, 1989, as to all persons except those persons to whom it was made immediately effective by priority letter AD No. 88-25-09, issued December 9, 1988, which contained this amendment. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
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