86-12-01 BELL HELICOPTER TEXTRON, INC.: Letter issued June 6, 1986. Applies to all Bell Model 214ST helicopters, certificated in all categories.
Compliance is required prior to further flight after receipt of this AD, unless previously accomplished.
To prevent loss of main rotor collective control, visually inspect locking plate, Part Number (P/N) 214-010-232-101, in accordance with Part I of Bell Helicopter, Textron, Inc., Alert Service Bulletin (ASB) 214ST-86-36, dated May 23, 1986. If the locking plate is defective, check the torque of the lower collective hub nut, Part Number 214-010-407-001, in accordance with Part IV of ASB 214ST-86-36. At the next "A" check, inspect the locking plate in accordance with Part II of ASB 214ST-86-36. At each subsequent "A" check, inspect the locking plate in accordance with Part III of ASB 214ST-86-36. At the next "B" check and each subsequent "B" check, check the torque of the lower collective hub nut, P/N 214-010-407-1, in accordance with Part IV of ASB 214ST-86-36.
An alternate method of compliance or adjustment of the compliance time, which provides an equivalent level of safety, may be approved by the Manager, Helicopter Certification Branch, Aircraft Certification Division, FAA, Southwest Region.
This airworthiness directive becomes effective upon receipt.