Story ID: 044
Cessna Citation Longitude Enters Service
By: Jerry Siebenmark
Caption: Textron Aviation has begun deliveries of its super-midsize twinjet following FAA type certification on Sept. 21.
Word Count: 599
With type certification of the Cessna Citation Longitude in hand and first delivery complete, Textron Aviation officials are hoping the super-midsize twin is on a similar path as the midsize Latitude—with a little help from NetJets, which has options for up to 175 Longitudes. “We will be delivering to NetJets later this year and that'll be exciting again to have [the Longitude] in their fleet, because we’ve seen what their participation can do with the program,” Textron Aviation senior v-p of sales and marketing Rob Scholl told AIN. “With the Latitude, it obviously got the airplane out there, people seeing it, people experiencing it. And I know having [NetJets] continue to fly that product is going to help us make that program another home run for the business.”

More than four years after its unveiling at the 2015 NBAA Convention in Las Vegas, Textron Aviation’s Cessna Citation Longitude received its long-awaited type certification on September 21 followed by entry into service on October 2. Scholl described the first recipient of the Longitude as a “retail customer.” With the NetJets order option, the first tranche of which includes 15, he hopes that stimulates additional orders as it did for the Latitude; 200 of which have been delivered in the first five years—100 of them to NetJets.

In what Textron Aviation called “the most robust flight, structural, and component qualification testing completed on a Citation to date,” the Longitude experimental and demo fleet, comprising five flight-test vehicles, completed nearly 6,000 hours of flight time, as well as 11,000 test points. During the certification process, the 3,500-nm-range Longitude also flew a 31,000-nm world tour. 

Certification of the $26.9 million airplane was originally expected about two years ago. 
Fuel Tank Issues
But at least one issue, fuel tank flammability, hampered Textron Aviation’s certification timeline for more than a year and a half while the manufacturer sought an exemption.

Textron Aviation’s initial appeal for exemption in February 2018 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 includes a portion covered by aerodynamic fairings. The company considers the entire fuel tank to be in a conventional unheated aluminum wing (CUAW) 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. A temporary exemption issued in August 2018 accepted an interim modification and called for a long-term solution. 

A second appeal made by Textron Aviation in December 2018 was 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.

In its June 26 decision granting the exemption, the FAA said: “the design modification that Textron has incorporated in the Model 700, to cool the fuel tanks and reduce fuel heating, improves the overall tank flammability to a level equivalent to a CUAW tank.”

The Longitude was Cessna’s first clean-sheet design since the midsize Citation Sovereign was certified in 2004.
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