Textron Aviation's flagship Cessna Citation Longitude has received provisional type certification from the FAA and deliveries of the super-midsize jet should begin early next year, the company announced today. “It’s a big step in the right direction,” Textron Aviation senior v-p of engineering Brad Thress told AIN.

Thress said the provisional certificate allows operators to “ops check” their Longitudes, including training on the aircraft in advance of taking delivery of them. Longitude customers could also take delivery of their airplanes under the provisional certificate, Thress acknowledged. “It’s possible,” he said.

The provisional certificate includes a number of limitations for the $26.9 million aircraft, the largest in the current Citation line. For one, it doesn’t allow the Longitude to be operated under RVSM conditions or for high elevation airport takeoffs and landings, according to the FAA. It also restricts maintenance on the Longitude’s electrical wiring interconnect systems to Textron Aviation. 

Moreover, the provisional certificate addresses the airplane’s fuel tank flammability requirements. Earlier this month Textron Aviation submitted a new exemption request from those requirements to the FAA, saying denial of the petition could disrupt deliveries and cause order cancellations.

The new request came after the FAA granted a time-limited partial exemption in August 2018. Textron Aviation’s initial appeal for exemption centered around a difference in interpretation between the FAA and the company on what constitutes a center fuel tank. The Longitude is designed with the fuel tank in a conventional unheated aluminum wing. But the system includes a portion covered by aerodynamic fairings. Textron considers the entire fuel tank to be in a conventional unheated aluminum wing that meets flammability requirements. 

But the FAA disagreed, determining that the portion covered by the aerodynamic fairings is not a conventional unheated aluminum wing tank, which means the aircraft doesn’t meet the requirements of FAR 25.981(b), amendment 25-125.

Textron Aviation's new appeal is more narrowly focused on the more extensive requirements that apply to the use of the flammability reduction means (FRM) in fuel tanks. The FAA has determined that the aircraft’s dedicated electric recirculation pump is an FRM and therefore the aircraft must meet those requirements.

Thress said Textron Aviation came up with “an innovative solution” to satisfy regulators but that “the regulation didn’t anticipate this type of solution." The FAA suggested the company file the December 5 exemption request that “corrects a regulatory misalignment,” Thress said.

He said this solution won’t require Textron Aviation to go back and retrofit Longitudes that have already rolled off the production line. “It does not,” Thress said. “The airplanes have the final solution installed.”