Pakistan Air Force F-16B models take part in a 2010 Red Flag exercise at Nellis Air Force Base, Nev. The Pentagon has told international operators of the F-16B model to inspect their jets for cracks. (Airman 1st Class Daniel Phelps / US Air Force)
WASHINGTON — As the Pentagon works to analyze and repair widespread cracks in its F-16D fleet, it is recommending that partner nations closely inspect their F-16B and D models.
Meanwhile, the US Air Force is bracing for a potential delay in training if the majority of its F-16D fleet is grounded for a significant period .
Cracks were first discovered on an F-16D model on July 31, and a Time Compliance Technical Order — a directive from the service — was quickly issued ordering the inspection of the entire F-16D fleet. That resulted in 82 of the service’s 157 F-16D models being grounded.
That inspection order applies to F-16B and F-16D models used around the world, an Air Force spokesman confirmed. While the US Air Force no longer operates the B model, Turkey, Israel, Belgium, the Netherlands, Pakistan, Denmark and Norway are among customers who would need to inspect their fleet.
A Pentagon news release referred to the damage as “canopy sill longeron cracks found between the front and rear pilot seats.” That is part of the frame of the aircraft that surrounds the cockpit area of the jet. When the canopy is lowered, it rests on the longeron.
Both the F-16B and F-16D are two-seat variants of the jet.
While it works out a solution to the damage, the service has begun planning how to contain the impact of a long-term grounding of the F-16D fleet.
“The Air Force is working with its F-16 operational units to mitigate the impact on operations, training, and readiness,” Maj. Carla Gleason, a spokeswoman for the service’s Air Education and Training Command, said in response to a query. “Programmed flying training and F-16D graduation delay impact will depend on the number and timing of aircraft returned to service. Subject matter experts are considering courses of action to mitigate these delays.”
“Initial estimates indicate flight training could be delayed 8-12 weeks.”
That number is just an estimate because each base has different windows when training flights can take place, driven by outside factors like weather.
According to initial Air Force figures, the largest number of cracked F-16D models were located at Luke Air Force Base, where all 35 planes were found to have cracks. Similarly, all 10 of the planes at Kelly Field Annex in Texas, operated by the Air National Guard, were cracked. Seventeen of the 18 F-16Ds kept at Tucson Air National Guard Base in Tucson, Arizona, were cracked as well.
The cause of the cracks is currently being investigated. Lockheed Martin, the prime contractor on the F-16, is “actively working with all F-16 customers to address the inspection findings,” company spokesman Mark Johnson said in a statement.
“The investigation into the cause of longeron issues is ongoing, so we don’t have contributing factors pinpointed at this time,” Benjamin Newell, a spokesman for Air Force Air Combat Command, said in a response to questions.
“A decade of near continuous operations have had an impact on all airframes, and we view the discovery of this issue as a testament to the soundness of our routine maintenance inspection processes and the thoroughness of Airmen responsible for aircraft maintenance.”
Newell added that Air Combat Command’s two F-16D models impacted by the cracks are expected to return to flight “within four to six months.”
A potential fix could be what is called an “external strap repair,” which would involve welding or drilling a support onto the longeron. Another option is replacing the longeron entirely, an invasive, and hence likely expensive, operation on the jet.
Those long-term solutions could begin being installed into the jet as soon as September.
In the meantime, the service is looking at smaller, potential fixes based around installing fasteners around the impacted area. Those fasteners could bring the planes an extra 50-100 hours of flight time before the larger fix would be needed. Those would only be installed on jets with lesser cracks, with the goal of using those extra flight hours to avoid training and operational delays.
The cracks reflect an “aging legacy fleet that is always starved for resources,” Richard Aboulafia, an analyst with the Virginia-based Teal Group, said. “We’re going to be dealing with the consequences of an aging attack fleet for years to come.”
He warned to expect similar issues as the fleet continues to age, particularly given the Air Force’s focus on recapitalization of new platforms over modernization of older ones — a choice that he added needed to be made given budget deficits and the need to keep the F-35 and long-range bomber programs on track.
The Air Force is well aware of the challenges to its aging fleet. In its budget request for FY 2015, the service decided to fund an F-16 Service-Life Extension Program (SLEP) over the Combat Avionics Programmed Extension Suite (CAPES).
While CAPES would have brought some much needed upgrades to the F-16 fleet, those upgrades would be useless if the aircraft can’t get off the ground. Aboulafia calls that an “interesting illustration” of how the Air Force is trying to keep its older jets flying.
“It shows that you’re not doing anything to enhance the combat effectiveness of the plane, you’re just preserving its life out of necessity,” Aboulafia said.