83-22-09 BRITISH AEROSPACE AIRCRAFT GROUP (HATFIELD-CHESTER DIVISION): Amendment 39-4754. Applies to Model HS 125 (pre-Modification 251600) with serial numbers listed in the Planning Information of the service bulletin. Compliance required as indicated, unless already accomplished. To protect the main engine beam from a burst failure of the cold air unit fan, accomplish the following:
A. Install a fragmentation guard around the fan housing of the cold air unit in accordance with the Accomplishment Instructions of British Aerospace Aircraft Group, Hatfield- Chester Division, 125 Series Aircraft Service Bulletin 21-123-(2815), Revision 2, dated October 29, 1982, within 120 days after the effective date of this AD.
B. Alternate means of compliance which provide an equivalent level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region.
C. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections and/or modifications required by this AD.
This amendment becomes effective December 1, 1983.