A new report from the Office of Special Counsel says the Federal Aviation Administration failed to ensure that Airworthiness Directives were issued in a timely manner resulting in unsafe conditions in some helicopters for a period of years.

The report says the oversight resulted in significant and potentially dangerous delays. The findings substantiate allegations made by a whistleblower who worked as an Aerospace Engineer assigned to FAA's Rotorcraft Directorate. The allegations said the FAA failed to issue directives on the airworthiness of the aircraft. The rules address unsafe conditions that are likely to exist or develop in other products of the same type design.

The investigation revealed that as of the end of 2009, the Directorate had a substantial backlog of unissued Directives. Three investigations had been open for approximately seven years.