US-based operators of Bombardier CRJ100 and 200 regional jets could be faced with a bill of more than $29.2 million to comply with a US Federal Aviation Administration (FAA) airworthiness directive that requires replacing liners in the aircraft's Class C cargo compartment.

The AD, issued today, requires operators to change the liners installed in the original aircraft's baggage hold because they do not meet flammability requirements. These liners "may not provide adequate fire protection and could lead to an uncontrolled baggage bay fire", said a Canadian AD referenced in a July notice of proposed rulemaking.

The FAA estimates that 574 US-registered aircraft would be affected by the AD and foresees required parts alone costing operators more than $43,500 per product. When adding in labour, the cost would increase to nearly $60,000 per product, or $29.2 million for the entire fleet.

The AD applies to series 100 and 440 Bombardier CL-600-2B19 regional jets with a Class C cargo compartment. These two aircraft types are also known as the CRJ100 and 200. Airlines must comply with the AD within 28 months from 17 April, when the directive becomes effective.

SkyWest Airlines is the largest CRJ200 operator, with 159 of the aircraft type in its fleet at the end of 2012. It says it has completed 17 aircraft modifications already and expects to incur costs of about $2 million related to the AD. Any aircraft that will be returned to lessors before the compliance timeframe ends would not be modified.

Some operators commented with concerns that the 28-month timeline would be too short. Regional airlines Air Wisconsin and Pinnacle Airlines filed requests to extend the 28-month compliance time to 36 months after the airworthiness directive goes into effect. Air Wisconsin operates a fleet of 71 CRJ200 aircraft, according to Flightglobal's Ascend Online database. Pinnacle has 140 CRJ200s in its fleet.

In August and September, the carriers also commented that Bombardier had yet to supply all of the necessary parts kits necessary for the modification. Air Wisconsin said that aircraft in the midst of heavy check visits were not able to receive the modification due to that fact.

Pinnacle said it could find itself needing to park aircraft without the necessary kits. In an update, the Memphis-based regional airline told Flightglobal that it does not foresee the directive impacting its operations given the compliance time.

Bombardier says it is in the process of working with operators to distribute the necessary parts.

"Bombardier has been proactively working with customers to define needs and is currently producing kits for the AD based on the order schedules provided by operators," says the airframer.

The directive would affect about 70 CRJ200s in Pinnacle's fleet, says the airline. It confirms it expects to incur costs from the modification, but it did not provide a cost estimate.

The FAA did not extend the timeline, adding that Bombardier confirmed with the FAA and Canada's aviation authority that the parts were available. It did say it will consider requests for extensions if the operators submit specific dates.

Pinnacle Airlines is planning for its 140 CRJ200 aircraft to exit its fleet in the next two to three years, at which point it would operate a fleet of 81 Bombardier CRJ900 aircraft on behalf of Delta Connection. The airline will become a Delta Air Lines subsidiary when it emerges from bankruptcy.

Air Wisconsin declined to comment on the AD.

Source: Air Transport Intelligence news