The F-35 is due to pass operational tests next month - a major milestone that precedes the Pentagon's decision on whether to begin mass production of the jet - but there are already some signs that the F35 could not being able to complete the tests in time.
In this regard the F-35 Joint Program Office is still assessing the impact of the recent inspection on the entire F-35 fleet due to faulty fuel lines.
The JPO, however, is confident the necessary repairs will be done ahead of the November operational tests.
The Pentagon aims to conclude the test and initial operational assessment, IOT & E, scheduled for July 2019, despite a two-month delay in starting testing.
The above, according to a presentation on September 14 by the director of tests for the F-35, the colonel of the USAF Varun Puri, reports Defense News.
"Most F-35 will return to flight activities after solving the fuel line problem."
To carry out the promptness of the F35 other very demanding tests will have to be carried out.
The presentation of Puri specifies a date, namely November 13th to begin the official IOT & E process of the F-35.
November 13 remains the scheduled departure date "pending the completion of operational readiness actions," said F-35 JPO spokesman Joe Della Vedova.
Last week all activities were suspended for all US and international F-35s to allow inspection of the jet fleet due to a faulty fuel pipe. This flaw was discovered in the Marine Corps investigation in a September 35 F-28B incident near the Marines Corp Air Station Beaufort in South Carolina.
On Monday morning, however, over 80% of the approximately 300 F-35 in service returned to fly and about half of the jets involved could be repaired using the spare parts already existing in the supply chain.
Pratt & Whitney, which produces the F135 engine for all F-35 variants, is speeding up operations to supply the required material to all control centers around the world.
The Joint Test Team of the Joint Strike Fighter, or JOTT, still believes it can complete IOT & E by the date of July 2019, but only "reducing the hypotheses of re-fly and taking more risks" - in other words -, lowering the tests that will need to be repeated to complete the program, leaving little room for flight cancellations due to weather conditions or other external factors.
In the "worst-case scenario," completion of operational tests could extend until September 2019, which could burden the program budget, Colonel Puri said during the presentation.
The operational tests will be performed as quickly and efficiently as possible, while ensuring the adequacy of the test, with continuous evaluations of progress towards test objectives based on the data collected, "said Della Vedova.
Initially, the formal IOT & E period was supposed to begin on September 15, but has been postponed to two months to allow for the delivery of the latest software release, named 30R02.03. Robert Behler, Director of Operational Testing and Evaluation (DOT & E), said in an August note that the new software was needed to correct deficiencies with the F-35 Air-to-Air infrastructure system, which will enable testers to evaluate the jet of the Jet, during remote tests.
Preliminary IOT & E activities began earlier this year and included two missions against low-end threats, cold tests and a close range support assessment.
Earlier this month, the Defense Department's chief acquisition officer - Ellen Lord, Undersecretary of Defense for Acquisition and Maintenance - certified that the F-35 was ready to begin IOT & E, concurrently With the F-35 Joint Program Bureau's recommendation to begin testing in mid-November, its spokesman Lieutenant Colonel Mike Andrews said in a statement. The decision was made after a review of operational readiness on 2 October.
Currently, the Department of Defense is ready to make a decision on full-rate production by the end of 2019, but IOT & E activities will need to be completed as soon as possible.