November 8, 2011: The U.S. Air Force will refurbish several hundred of its 22 ton F-16 fighters, because their replacement, the 31 ton F-35 is not arriving in time. The F-35 began development in the 1990s and was supposed to enter service in 2011. That has since slipped to 2017, or the end of the decade, depending on who you believe. Whichever date proves accurate, the air force has a problem. Its F-16s are old, and by 2016 many will be too old to operate. The average age of existing F-16s is over 20 years, and the average aircraft has over 5,000 flight hours on it. Two years ago, the first Block 40 F-16 passed 7,000 hours. Three years ago, the first of the earliest models (a Block 25) F-16 passed 7,000 hours.

Depending on how late the F-35 is, the air force will refurbish 300-600 Block 40 and 50 aircraft. The work will concentrate on extending the life of the airframe, plus some electronics upgrades. The air force does this sort of thing frequently to all aircraft models. It's called SLEP (Service Life Extension Program), and this one is special only because it concentrates on very old aircraft and is intended to keep these birds viable for another 5-10 years.

The F-16C was originally designed for a service life of 4,000 hours in the air. But advances in engineering, materials and maintenance techniques have extended that to over 8,000 hours. Because of the wars in Iraq and Afghanistan, F-16s sent to these areas will fly over a thousand hours a year more than what they would fly in peacetime. The current planned SLEP will extend F-16C flight hours to 10,000 (10K) or more.

The F-16 has proved to be remarkably adaptable and is one of the most modified jet fighters in service. The most numerous F-16 is the C model. The first version of this, the F-16C Block 25, entered service in 1984. The original F-16, as the F-16A Block 1, entered service in 1978. While most F-16s still in service are the F-16C, there are actually six major mods, identified by block number (32, 40, 42, 50, 52, 60), plus the Israeli F-16I, which is a major modification of the Block 52. Another special version (the Block 60), for the UAE (United Arab Emirates) is called the F-16E. The F-16D is a two seat trainer version of F-16Cs. The various block mods included a large variety of new components (five engines, four sets of avionics, five generations of electronic warfare gear, five radars and many other mechanical, software, cockpit and electrical mods.)

The F-16 is the most numerous post-Cold War jet fighter, with over 4,200 built, and still in production. During The Cold War, Russia built over 10,000 MiG-21s, and the U.S over 5,000 F-4s, but since then warplane production has plummeted about 90 percent. One exception, since the end of the Cold War, has been the F-16, which has been popular enough to keep the production lines going.

The F-16 can also function as a bomber and ground attack aircraft, although not as effectively as the air force experts would have you believe. It can carry four tons of bombs, and has been very effective using smart bomb. In air-to-air combat, F-16s have shot down 69 aircraft so far, without losing anything to enemy warplanes. Not bad for an aircraft that was originally designed as a cheaper alternative to the heavier F-15.

The two most advanced versions of the F-16 are in use by foreign air forces. The UAE has 80 "Desert Falcons" (the F-16E) which is optimized for air combat. It is a 22 ton aircraft based on the Block 52 model, but with an AESA (phased array) radar and lots of other additional goodies.

The Israeli F-16I is optimized for bombing. It's a 24 ton, two seat aircraft, and is probably the most capable F-16 model in service. It's basically a modified version of the Block 52, equipped with a more advanced radar (the APG-68X) and the ability to carry Israeli weapons like the Python 4 air-to-air missile and the Popeye 2 air-to-surface missile. Costing $45 million each, the F-16I has an excellent navigation system, which allows it to fly on the deck (100 meters/300 feet from the ground), without working the pilot to death. The aircraft can do this at night or in any weather. The F-16I can carry enough fuel to hit targets 1,600 kilometers away (meaning Iran is within range). The aircraft uses the latest short and long range air-to-air missiles, as well as smart bombs. Electronic countermeasures are carried, as is a powerful computer system, which records the details of each sortie in great detail. This is a big help for training. The F-16I is basically optimized to deliver smart bombs anywhere, despite dense air defenses. This further increases Israel's military power versus its neighbors. Israel has received 102 new F-16I fighter-bombers in the last five years. Added to this will be another 125, as older F-16s are upgraded.

Although the F-35 is designed to replace the F-16, many current users will probably keep their F-16s in service for a decade or more. The F-16 gets the job done, reliably and inexpensively. Why pay more for new F-35s if your potential enemies can be deterred with F-16s. This becomes even more likely as the F-35 is delayed again and again.