| AD Number | 88-12-03 | Status | Active |
| Effective Date | April 09, 1990 | Issue Date | Not specified |
| Docket Number | 88-ASW-32 | Amendment | 39-6539 |
| Product Type | ["Aircraft"] | Product Subtype | ["Rotorcraft"] |
| CFR Part | --- - Part 39 | CFR Section | N/A |
| Citation | This information is not available. | ||
| Manufacturer(s) | Bell Helicopter Textron, Inc. |
| Model(s) | 214ST |
88-12-03 BELL HELICOPTER TEXTRON, INC. (BHTI): Amendment 39-6539. Final copy of priority letter AD. Docket No. 88-ASW-32.
Applicability: Bell Model 214ST helicopters, serial numbers 28101 through 28195 and 18402, certificated in any category.
Compliance: Required as indicated, unless already accomplished.
To prevent failure of the main rotor (M/R) drag brace assembly which could result in subsequent loss of the helicopter, accomplish the following:
(a) For each M/R drag brace assembly, part number (P/N) 214-010-113-105, with 250 or more hours' time in service, inspect within the next 10 hours' time in service and thereafter at intervals not to exceed 250 hours' time in service as follows:
(1) Remove drag brace assembly to the blade attachment bolt, P/N 20-057- 16-68D, and the drag brace to the grip attachment bolt, P/N 20-057-16-92D.
(2) Measure length of each drag brace assembly, then disassemble and thoroughly clean all parts.
(3) Inspectthe barrel, P/N 214-010-120-107; the clevis, P/N 214-010-121- 105; and the nuts, P/N 214-010-198-101, for corrosion pitting and mechanical damage. Remove the part from service if pitting is found in the threads.
NOTE: If corrosion pitting or mechanical damage is superficial, it may be polished out.
(4) Remove paint and primer for inspection.
(5) Inspect each drag brace barrel for cracks using a magnetic particle or fluorescent penetrant method. Pay special attention to the threaded area.
(b) If cracks are found, or if corrosion pitting or mechanical damage is found which exceeds a maximum depth of 0.010 inch, replace with serviceable parts.
(c) Assemble and install the drag brace as follows:
(1) Threads of barrel which have cadmium plating removed during disassembly must be brush cadmium plated or protected. Coat threads of the drag brace barrel, nuts, and the inner surface of clevis with either corrosion preventive compound MIL-C-16173, Grade 2 orGrade 3, or an equivalent.
(2) Reassemble and reset the length of the drag brace as measured in the requirements of paragraph (a)(2). Torque inboard nut 375 to 425 foot pounds, while holding outboard nut.
(3) Reinstall the drag brace assembly and torque inboard and outboard attachment bolt nuts, 225 to 400 foot pounds.
(4) After final drag brace adjustment, if required, clean the exterior of the drag brace assembly. Coat the threads, nuts, and clevis area with MIL-C-16173, Grade 1 (drying), corrosion preventive compound or equivalent.
(d) Whenever a new design drag brace assembly, P/N 214-010-191-101, is installed in accordance with BHTI Alert Service Bulletin (ASB) 214ST-88-47, Revision A, dated February 20, 1989, this AD no longer applies.
(e) An alternate method of compliance or adjustment of the compliance time, which provides an equivalent level of safety, may be used if approved by the Manager, Rotorcraft Certification Office, FAA, Southwest Region,4400 Blue Mound Road, Fort Worth, Texas.
(f) In accordance with FAR Section 21.197 and 21.199, the helicopter may be flown to a base where the inspection may be accomplished.
This amendment becomes effective April 9, 1990, as to all persons except those persons to whom it was made immediately effective by Priority Letter AD 88-12-03, issued on June 3, 1988, which contained this amendment.