RAF FAIRFORD, England — While the Air Force may have developed a hint of second thoughts on the F-35A's ejection seat, aircraft manufacturer Lockheed Martin has not been approached by the joint program office to weigh alternatives, a company official said Thursday.

Defense News broke the story last month that the service is considering the certification of United Technologies' ACES 5 design as a fallback to the currently planned Martin-Baker US16E seat. Lt. Gen. Arnold Bunch, the Air Force's top uniformed acquisition official, said then that the service was studying the cost and logistics of adopting a different seat as a risk-mitigation measure in case the Martin-Baker equipment failed to meet safety requirements.

Jeff Babione, Lockheed's executive vice president and general manager of the F-35 program, noted that Lockheed has not been asked by the joint program office to assess the ACES 5 seat, but would be willing to do so if the government deems it necessary. He declined to speculate about the impact of integrating an alternative seat to the F-35's cost and schedule.

"The details of the kind of testing, cost and schedule of integrating another seat would really be out of scope right now," he said during an exclusive interview ahead of the Royal International Air Tattoo here. "If the JPO decides that they would like Lockheed Martin to look at that, we're there to support, but right now we're focused on finishing Martin-Baker integration and I have complete confidence that that's going to be a success."

Last year, the Air Force found that pilots weighing less than 136 pounds were at risk of severe neck injury when ejected from the F-35. Martin-Baker has since incorporated a number of fixes into its seat, including adding a head support panel to prevent injury when the parachute is deployed, and modifying its software to lessen the impact on pilots of the parachute deploying.

Martin-Baker and the F-35 JPO have released statements to Defense News contending that the modified seat will demonstrate improved pilot safety, and Babione echoed that view.

"We have every confidence with the latest changes that the seat will be fully qualified for all weights, sizes and heights of pilots that the F-35 can be certified for," he said. "And I think that will all be resolved by the end of this fall."