Thousands of Piper Aircraft owners are required to inspect a historically problematic component for cracks and make replacements as necessary.

The airworthiness directive published on 5 February affects 34,013 aircraft in the US registry - the entire fleet of PA-28 Cherokees, PA-32 Cherokee Sixes, PA-34 Senecas and PA-44 Seminoles older than 15 years.

The US Federal Aviation Administration estimates the cost of the 5h inspection on the horizontal stabilator control system at $425 per aircraft, or $14.5 million across the US fleet. Replacement parts and labour adds another $1,458 per aircraft to the total bill.

Piper owners and federal regulators have long been aware of failures caused by assembly errors on a Bell-Memphis-built turnbuckle in the horizontal stabilator. Investigators have linked the problem to 14 failures on Pipers and one on a Cessna 172.

In 2001, the FAA required annual inspections of the horizontal stabilator, but instances of turnbuckle failures continued. On 14 March 2012, a Cherokee Six crashed while landing in Warrenton, Virginia after losing elevator control because of a fractured turnbuckle in the lower stabilator control cable.

The annual inspection to check for cracks in the same component had been completed the previous day but failed to prevent the fracture, it states in the investigation report by the National Transportation Safety Board.

In August, the FAA proposed a new rulemaking requiring another round of inspections and replacement parts, but this time making the checks mandatory to maintain airworthiness of the aircraft.

Piper has previously recommended inspections of the control cable assembly, issuing two service bulletings to operators since 2010.

"Piper is proud of its overall fleet safety record and is diligent in assuring the safest operations possible for the thousands of Piper owners and operators throughout the world," the comapny says.   


Source: Flight International