# AD 73-12-01: Vertical Fin Skin Cracks

- Type: Airworthiness directive
- Status: Current
- Products: Bell Helicopter Textron Canada 206A, 206A-1 (OH-58A), 206B and 206B-1
- Effective: July 1, 1973
- Superseded by: Nothing supersedes this AD
- Product type: Aircraft, Rotorcraft
- Amendment: 39-1650
- Registered aircraft: 861 may be affected, by airframe or engine model (OpenAirDocs)
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/E1F76B739446DA3386256A340053769B.0001
- DRS record last changed: May 30, 2024
- Page: https://openairdocs.org/ad/73-12-01

## The airworthiness directive

73-12-01 BELL: Amendment 39-1650. Applies to Model 206A and 206B helicopters, serial numbers 4 through 865 and 867 through 873, certificated in all categories, equipped with vertical fin, P/N 206-020-113-5, -7 and -9.

Compliance required within the next 25 hours' time in service after the effective date of this A.D., unless already accomplished within the last 25 hours' time in service, and thereafter at intervals not to exceed 25 hours' time in service from the last inspection.

To detect possible fatigue cracks in the skin of the vertical fin in the area of the tail boom attachment, accomplish the following:

  (a) Remove all tail fairing assemblies to gain access to the inboard side of the vertical fin assembly.

  (b) Visually inspect the inboard skin of the vertical fin in the area of attachment for any cracks, paying particular attention to the area aft of the upper rear attachment insert.

  (c) If any crack is found greater than 3.5 inches in length, removeand replace the fin before further flight.

  (d) If any crack is found less than 3.5 inches in length, remove and replace or repair the fin in accordance with Part II of Bell Helicopter Company Service Letter No. 206-203, Revision C, dated March 14, 1973, or later FAA approved revision, before further flight.

  (e) If no cracks are found, continue the repetitive inspections specified above.

  (f) This A.D. is no longer applicable when the fin is modified in accordance with Part I or II of Bell Helicopter Company Service Letter No. 206-203, Revision C, dated March 14, 1973, or later FAA approved revision.

(Bell Helicopter Company Service Bulletin No. 206-01-73-1, dated January 9, 1973, pertains to this subject.) This amendment becomes effective July 1, 1973.

## Affected data sheets (1) (OpenAirDocs)

The type certificate data sheets whose models the AD names.

- [TCDS H2SW](https://openairdocs.org/tcds/H2SW): Bell Textron Canada Limited; names 4 of 12 models: 206B, 206A, 206B-1, 206A-1 (OH-58A)

## Registered aircraft it may apply to (OpenAirDocs)

Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment.

- Aircraft: 861 (861 by airframe model, 0 by engine model)
- Makers: Bell 822, Bell Helicopter Textron 29, Bell Helicopter Textron Canada 10

Models with the most aircraft:

- [Bell 206B](https://openairdocs.org/model/bell-206b): 790 aircraft (airframe model)
- [Bell Helicopter Textron 206B](https://openairdocs.org/model/bell-helicopter-textron-206b): 29 aircraft (airframe model)
- [Bell 206A](https://openairdocs.org/model/bell-206a): 23 aircraft (airframe model)
- [Bell Helicopter Textron Canada 206B](https://openairdocs.org/model/bell-helicopter-textron-canada-206b): 10 aircraft (airframe model)
- [Bell 206A-1](https://openairdocs.org/model/bell-206a-1): 6 aircraft (airframe model)
- [Bell 206B II](https://openairdocs.org/model/bell-206b-ii): 3 aircraft (airframe model)

All 6 models: https://openairdocs.org/ad/73-12-01/models.md
Every aircraft: https://openairdocs.org/ad/73-12-01/aircraft.md

Its text cites no advisory circulars or STCs.

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