September 20, 2017:
Another sign of the worsening U.S. relations with Turkey occurred recently when the Americans refused a Turkish request to provide (or allow Turkey to recruit) pilot instructors to help rebuild the depleted ranks of Turkish F-16 pilots. Pakistan was the only major F-16 user that agreed to provide some pilot instructors but the Americans blocked that as well.
This is a serious problem for the Turkish Air Force because the July 2016 coup attempt in Turkey had many victims and one of the lesser known ones was the effectiveness of Turkish fighter fleet. While few F-16 pilots took part in the coup, the government lost (through dismissal or resignation) 274 combat pilots. This reduced the ratio of pilots per F-16 from 1.25 to .8. Suddenly the combat capabilities of the Turkish air force were greatly reduced, especially if the F-16s were called on to engage in large scale and intensive operations.
Turkey has long had one of the largest F-16 fleets in the world, with about 240 F-16s currently in service. Because they belonged to NATO the Turks had to achieve high standards of pilot training, especially the number of flight hours per pilot per year and the number of pilots per aircraft. Until 2016 Turkey maintained these standards with F-16 pilots getting over 150 flight hours a year and there were 1.25 pilots per F-16. This pilots per aircraft ratio is important because aircraft can fly more frequently per day than one pilot can handle. So it you want to get maximum use of modern combat aircraft you need a ratio of at least 1.25 and preferably 1.5. American aircraft carriers, for example, carry 1.4 pilots per combat aircraft.
This higher pilot-to-aircraft ratio becomes crucial in wartime when the most effective air forces can fly a lot more sorties per day. This is called the surge rate. During “surge” operations aircraft are called on to carry out the maximum number of sorties for a day or so. This was the kind of capability that long gave Western air forces a big advantage and has been demonstrated regularly since the 1960s.
To achieve and maintain the ability to surge you also need a lot of "maintainers" (of the aircraft) capable of working 12 hour shifts. These well trained ground crews can turn a returning aircraft around in 15 minutes, complete with a new pilot, fuel, and weapons, plus a quick check for equipment problems. For example, an F-16 squadron has 12 aircraft (plus spares for replacements) and a unit of 120 maintainers, including 37 NCOs ("Crew Chiefs") who supervise and do a lot of the work. One American F-16 squadron used its 20 aircraft, forty pilots, and very energetic and well trained ground crews to fly 160 sorties in 12 hours. This was an exceptional performance and not representative of combat conditions, where many aircraft would come back with combat damage. This also points out the need to have more pilots than aircraft, as the pilots are more fragile than the aircraft they fly. U.S. Navy carriers often carry out over 120 sorties a day.
Some of the Turkish Air Force maintainers were lost due to the post-coup purge and that was less of a problem. Turkey is one of the few Moslem countries that have a large number of locals with the technical skills and experience to maintain jet aircraft. For that reason the Turks get a lot of business maintaining and upgrading commercial and military aircraft, especially from other Moslem nations. But without the right pilot ratio the skilled maintainers will not have to deal with high surge rate training and combat operations.