Citation Longitude
As of October, Textron was on track for fourth-quarter certification and deliveries of its flagship Longitude. (Photo: Jerry Siebenmark)

Textron Seeks New Longitude Fuel Tank Exemption

Textron Aviation has submitted a new request for an exemption from the Federal Aviation Administration’s fuel tank flammability requirements for its flagship Cessna Citation Longitude jet. Denial of the petition could disrupt deliveries and cause cancellations of orders for the $26.9 million super-midsize jet, according to the petition that was recently posted in a Federal Register notice.

The new exemption request comes after the FAA granted Textron Aviation a time-limited, partial exemption in August 2018. That exemption was necessary to clear the way for certification of the aircraft. The Wichita manufacturer told BJT sister publication Aviation International News  that the new request serves as a final solution to the fuel tank flammability issue.

Textron Rolls Out First Production Citation Longitude

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Textron Rolls Out First Production Citation Longitude

There are currently five of the super-midsize twinjets on the production line.

“This is the permanent means of full compliance with the regulation,” the company said. “The purpose of the new exemption is to align the Citation Longitude compliant fuel system design with the regulation, which did not anticipate the type of solution used.”

The company added that it does not expect the new exemption request to “impact the Citation Longitude certification timeline,” although Textron Aviation didn’t have an update on when certification might occur.

On a third-quarter 2018 earnings call with analysts on October 18, Scott Donnelly, CEO of parent company Textron Inc., said the Longitude program was still on track for fourth-quarter 2018 certification and deliveries.

Textron Aviation’s initial appeal for exemption centered on 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.

In its earlier exemption request, Textron pointed to the safety records of other jets in its fleet with similar fuel systems such as the Citation Sovereign and M2, as well as the Hawker 4000. The temporary exemption accepted an interim modification and called for a long-term solution. 

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.

“For the Model 700 (Longitude) to meet the requirements…significant modifications to the current fuel system design would be required,” the company said in its December 6 exemption request, adding that such a redesign could require significant structural changes and changes to other systems as well.

“Given the extensive nature of these changes and the required ground and flight certification testing related to them, FAA approval could not be completed by July 31, 2019 as required by Time-Limited Exemption 179413,” Textron Aviation said. “This would result in a disruption of production deliveries and potentially a disruption to the operators if design changes could not be incorporated by Jan. 31, 2020, as required by Time-Limited Exemption 17941.” 

Denial of this latest exemption request “would result in the disruption of production deliveries of the Model 700, causing TXTAV to experience a significant loss of revenue,” Textron Aviation said.  “This could also result in numerous aircraft order cancellations, increasing the financial loss significantly.”

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