AD 53-09-03
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Hiller Aviation | UH-12 | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. |
| aircraft | Hiller Aviation | UH-12A | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. |
| aircraft | Hiller Aviation | UH-12B | Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. |
Unsafe Condition
Fatigue failure of the clevis head on the outboard tension torsion bar pins, P/N 51414-1.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Inspect P/N 51414-1 pins to determine the fillet radius under the clevis head. Replace pins with radius less than 0.030 inch before further flight. Replace all pins after accumulating 500 hours of flight time.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
As soon as possible but no later than the next 25-hour inspection and as indicated in part C below.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Outboard Tension Bar Pins
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_53-09-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 53-09-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. Subject: Outboard Tension Bar Pins Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation Model: UH-12 | UH-12A | UH-12B Product Type: Aircraft Product Subtype: Rotorcraft Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 53-09-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 53-09-03 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 53-09-03 HILLER: Applies to All UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Model Helicopters. Compliance required as soon as possible but no later than the next 25-hour inspection and as indicated in part C below. The following has been found necessary to prevent fatigue failure of the clevis head on the outboard tension torsion bar pins, P/N 51414-1: A. Inspect P/N 51414-1 pins to determine the fillet radius under the clevis head. If radius is less than 0.030 inch the pin must be scrapped and replaced with a pin having at least 0.030-inch radius before further flight. B. If radius is 0.030 or greater and the pin has less than 500 hours total time it may be reinstalled. If a featheredge is found at the base of the clevis it should be carefully removed. C. All 51414-1 pins must be replaced when they have accumulated a total of 500 hours of flight time. (Hiller Service Bulletin No. 36 covers this procedure.) FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_53-09-03.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 53-09-03 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. Subject: Outboard Tension Bar Pins Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: Make: Hiller Aviation Model: UH-12 | UH-12A | UH-12B 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: 53-09-03 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: AD NUMBER: 53-09-03 SUBJECT HEADING: Airworthiness Directives; Hiller Models UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Helicopters. ACTION: SUMMARY: DATES: ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 53-09-03 HILLER: Applies to All UH-12, UH-12A, UH-12B, HTE-1, HTE-2, H-23A and H-23B Model Helicopters. Compliance required as soon as possible but no later than the next 25-hour inspection and as indicated in part C below. The following has been found necessary to prevent fatigue failure of the clevis head on the outboard tension torsion bar pins, P/N 51414-1: A. Inspect P/N 51414-1 pins to determine the fillet radius under the clevis head. If radius is less than 0.030 inch the pin must be scrapped and replaced with a pin having at least 0.030-inch radius before further flight. B. If radius is 0.030 or greater and the pin has less than 500 hours total time it may be reinstalled. If a featheredge is found at the base of the clevis it should be carefully removed. C. All 51414-1 pins must be replaced when they have accumulated a total of 500 hours of flight time. (Hiller Service Bulletin No. 36 covers this procedure.) 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.
Related Airworthiness Directives
2000-24-21
final ruleAirworthiness Directives; Siam Hiller Holdings, Inc. Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, UH-12E-L, UH-12L, and UH-12L4 Helicopters
Unsafe Condition: Separation of the control system linkage at pivoting joints in the control system, leading to loss of control of the helicopter.
97-20-15
final ruleAirworthiness Directives; Hiller Aircraft Corporation Model UH-12A, UH-12B, UH-12C, UH-12D, and UH-12E Helicopters
Unsafe Condition: Cracks in the head area of the outboard tension-torsion (T-T) bar pin could result in loss of in-plane stability of the main rotor blade and subsequent loss of control of the helicopter.
97-10-16
final ruleAirworthiness Directives; Hiller Aircraft Corporation Model UH-12, UH-12A, UH-12B, UH-12C, UH-12D, UH-12E, CH-112, H-23A, H-23B, H-23C, H-23D, H-23F, HTE-1, HTE-2, and OH-23G Helicopters
Unsafe Condition: Separation of the control rotor blade assembly and subsequent loss of control of the helicopter due to corrosion, cracks, elongation, corrosion, burrs, pitting, or fretting of the bolt holes in the...
90-15-01
final ruleAirworthiness Directives; ROGERSON HILLER CORPORATION (HILLER, FAIRCHILD HILLER) Model UH-12E, UH-12E-L, UH-12L, and UH-12L4 Series Helicopters
Unsafe Condition: Failure of a tail rotor blade assembly, which could result in loss of controllability of the helicopter.