COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY
SCHEDULE OF AIRWORTHINESS DIRECTIVES
Allison Turbine Engines - 250 Series
AD/AL 250/62
Amdt 1
Fourth Stage Nozzle Assembly - Replacement 7/85
Applicability: All model 250-C30, C30 (Hughes), C30P and C30S with serial numbers as listed in the requirement document and, turbine assemblies incorporating P/N 23008470 or 6898694 fourth stage nozzle assy.
Requirement: Allison 250-C30 series CEB-A-72-3122 Rev.1.
Compliance: Prior to completion of the next overhaul after 31 December 1984 or on the next occasion the power turbine is disassembled.
Background: This directive is amended to reflect the manufacturers CEB-72-3122 Rev 1 which revises affectivity, changes rework dimensions, and adds the latest nozzle part number and references.
There have been instances of rubbing contact between the third stage turbine wheel and the inner band of the fourth stage nozzle.