Airworthiness Directive 04-15508
one-timeAirworthiness Directives; Rolls-Royce Corporation (Formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) Models 250-C28, -C28B, and -C28C Turboshaft Engines
What this AD requires
The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce Corporation (formerly Allison Engine Company, Allison Gas Turbine Division, and Detroit Diesel Allison) (RRC) models 250-C28, - C28B, and -C28C turboshaft engines with certain serial number (SN) third-stage turbine wheels, part number (P/N) 6899383. This AD requires replacing certain SN third-stage turbine wheels, P/N 6899383, before reaching new reduced life limits. This AD results from three reports of third-stage turbine blade and shroud failures. We are issuing this AD to prevent loss of power and uncommanded engine shutdown due to failure of third-stage turbine blades and shrouds.
Which aircraft AD 04-15508 applies to
Applies only to third-stage turbine wheels, part number 6899383, listed by specific serial number in Table 1 of the AD (approximately 75 discrete, non-contiguous serial numbers with prefixes HX9192x-HX9198x and X52323x-X52332x; not expressible as a simple contiguous from/to range). Installed on, but not limited to, Bell Helicopter Textron 206L-1, Eurocopter Deutschland BO 105 LS A-1, and Eurocopter Canada BO 105 LS A-3 helicopters.
Whether AD 04-15508 actually applies to your aircraft (by serial and installed parts) and whether it’s already complied with comes from that aircraft’s records.
How AD compliance is recorded
A valid compliance record (14 CFR 43.9) states:
Tailplate reads a tail number’s logbooks and matches every applicable AD — including this one — to its compliance evidence, with recurring next-due dates computed.
Look up a tail number →Read the full directive (Federal Register)Applicability is derived from the FAA directive corpus and is advisory, not a legal airworthiness determination. Compliance is established only from an aircraft’s actual records.