Everything bad said about "Concurrency", has a poster child called the "F-35". The concurrency issue suggest, when will it ever be complete? The answer is never! An unsettling and unnerving answer with any old fashion common sense observer of everything military. That class of observer are the noise makers about how bad the F-35 program has become and the F-35 should be scrapped. If you are a "Block" person it is progressing exceedingly well. If you are a "Program" person you think it's a disaster!
The first group of people are the "Block Testers". Somewhere, someone has to draw a line in the sand in the form of a block (?) production line drawn. The F-35 is currently well within Block three production and development concurrently. The complaints are about aircraft computer code updates, concurrent failures and costs. However, everything nice said about the F-35 comes from within a block development engineering and testing phase, and everything bad comes from within unresolved issues going forward.
First big reported item was the Pilot's Helmet. It had to be reengineered and tested. Followed by the continuous computer codes upgrades never ceasing while threatening its war time availability. In fact some data must update every time an F-35 receives a mission assignment. Something older generation aircraft never had to do. The F-15 or F-16 just flew and struck with autonomy. Once again the old school war fighters raised a ruckus over the dependency of updating during a wartime scenario. It could be said by any observer watching, the "Great War" is the making of the F-35.
However, there are those who are always faithful, Semper Fi, and the US Marines come into the fight battling for its bird. The F-35B becomes operational before its partners with the Airforce or Navy are even ready. What has occurred is the F-35B is so far superior replacing the AV8 Harrier, it makes the Marines more dangerous for any adversary. A Mach 1.6 VTOL fighter not needing an airport is an insane proposition. The Marine’s main criticism for the F-35B, it needs a hot plate to land or take-off on. I would suggest placing reinforced NASA shuttle type heat tiles on any deck but who would listen?
Concurrency has been around long before the word was used in the military vernacular. The concurrency battle also goes with the F-18 world as it receives its upgrades on a continuous basis. Even the rugged A-10 has received new avionics and systems upgrades as applied over the last five years. The Block production is a "temporary line in the sand" for the F-35. What is so confusing is where do all the issues reside? Is it a block II,III, or IV issue which makes it sound like all the collective problems are mounting towards a calamity of errors for the F-35 program. The fact is many of the problems have already been retired. Perception is the wheelhouse for old school thinking.
It is also known concurrency does have several plates spinning in the air at any given moment. When Block III production initiates, block II production units are already in field, and will be upgraded where possible, to a Block III levels and so forth. Concurrency does not ever have a line in the sand where it stops and waits for the next block production run. Every day the development gyrations continue only having an organizational cut-off within a period time where its improvements and issues resolutions never stops. As said by others, the F-35 may reach its full development vision during the next 20-30 years in service. What is important are the current F-35's in-field meeting operational standards for the level of development it represents?
The biggest problem is costs, and where its growth is mitigated with some defined value per aircraft delivered. The F-18 has a rising cost factor always, even as the F-35 is in its awkward years making its first stumbling steps. Whether the Taxpayer, Congress, or the DOD are patient enough and have faith in making its ultimate F-35 will be settled only when defending this country. That is the billions of dollars on the faith question presented before all of us. Can the F-35 reach its vision with enough time and money thrown at it? Many old schoolers have lost faith in this concurrency program, and want to scrap it out for any other unknown program. Unfortunately that will cost this nation a decade of time which may be more costly than the money already spent to date for the F-35.