The most expensive fighter program in history just handed the U.S. Marine Corps six brand-new stealth jets that cannot see. In place of their radar, each F-35B carries a chunk of dead weight bolted into the nose to keep the jet balanced. The Marines accepted them anyway.

It sounds like a punchline. It is not. The new radar these aircraft were built around is running years late, the older radar physically does not fit, and Lockheed Martin's production line is the largest in the fighter world — you do not simply switch it off and wait. So the jets roll out, weighted nose-down by ballast, and the radars get retrofitted whenever they finally arrive.

And the Marines are only first in line. The Air Force and the Navy are expected to start signing for radar-less F-35s of their own before the year is out.

A stealth fighter with a paperweight where its eyes should be

Strip away the jargon and the situation is almost comic. The AN/APG-85 active electronically scanned array radar is the sensor that turns the F-35 from a fast jet into a flying battle-manager — it finds targets, builds the picture, cues the missiles. Pull it out and you are left with a very expensive, very stealthy trainer.

That is exactly what the Marines have on their hands. The six F-35Bs entered acceptance testing in February 2026 and are cleared for basic flight training and not much else. No combat training. No operational missions. Just keeping pilots current while everyone waits on a radar.

To keep the jets safe to fly without the radar's mass in the nose, technicians install ballast — literal weights — to hold the center of gravity where the flight-control computers expect it. A fifth-generation fighter, balanced by what amounts to a fancy brick.

So why not just bolt in the old radar?

Reasonable question. The previous-generation AN/APG-81 has worked beautifully on F-35s for years. The problem is mechanical, not electronic. Starting with Lot 17 aircraft, the jets are built with a redesigned nose bulkhead and mounting arrangement tailored to the bigger, more capable APG-85.

That new mounting will not take the old radar without major structural surgery on a brand-new airframe — which nobody wants to do. The two radars are simply not interchangeable. So the choice came down to this: park finished jets indefinitely, or deliver them now, fly them lightly, and slot the radars in later. The program chose the latter.

There is a contractual wrinkle too. The radar is government-furnished equipment, bought separately by the Pentagon, which means the schedule slip lands on radar-maker Northrop Grumman — not on Lockheed Martin, which built perfectly good aircraft on time.

“Concurrency” comes home to roost

That statement is bureaucratic armor, but it is also an admission. “Concurrency” means building and upgrading the aircraft at the same time, betting that the new tech will be ready when the jets are. It is the F-35 program's oldest gamble — and here it has produced finished fighters that arrived ahead of the capability they were designed to carry.

On June 23, the F-35 Joint Program Office director, Marine Corps Lt. Gen. Gregory Masiello, told the Senate Armed Services Committee's Airland Subcommittee that the six Marine F-35Bs are the only aircraft delivered without radars so far. The key word is so far.

The Air Force and Navy are next — and the clock runs to 2028

If the radar deliveries stay slow, the Air Force and Navy are expected to start accepting their own radar-less F-35s later in 2026. The Air Force had not taken one in this configuration as of the June hearing, but officials have signaled it is coming.

The deeper number is the timeline. The first production lot of the AN/APG-85 is now projected to arrive no sooner than 2028. Until then, every ballast-fitted jet is a placeholder — a stealth airframe waiting on the sensor that makes it a weapon. The aircraft are not broken. They are unfinished, and the missing piece is years out.

It is a strange image to end on: some of the most advanced fighters ever built, sitting on the ramp, perfectly capable of flying and utterly unable to fight, balanced by a weight where their radar should be. The Marines took them anyway. Given the alternative — an idle production line and empty squadrons — they did not have much choice.

Sources: Air & Space Forces Magazine; Aviation Week; The War Zone (TWZ); Breaking Defense; testimony before the Senate Armed Services Committee Airland Subcommittee, 23 June 2026.