Why was the f22 cancelled?

Answer 1

There have been several reports as to the F-22's overall mission ready rate and maintenance requirements.

Lockheed-Martin's F-22 spokesman says that the overall mission ready rate has improved from 62% in 2004 to 68% in 2009, and is "on track" to reach 85% by the time the fleet reaches 100,000 flight hours.[173] The Washington Post says that between October 2008 and May 2009, just 55 percent of the deployed F-22 fleet has been available.[174] Air Force Magazine reported that the Washington Post article's was incorrect and that mission capable rates have been climbing, and by June 2009 stood at 62.9%, compared to approximately 70% for the mature F-15 and F-16 aircraft.[175][176] The Air Force Association states that the current mission capable rate for the entire F-22 fleet is 70%,[177] which is in line with the 71.2 percent the even newer Super Hornet managed on its first wartime deployment.[178]

In July 2009, the Air Force reported that the F-22 requires more than 30 hours of maintenance for every flight hour, with the total cost per flight hour of $44,000.[174] The Office of the Secretary of Defense puts that figure at 34 hours of maintenance per single hour of flight at a cost of $49,808 per hour of flight. The Pentagon requirement is for 12 hours of maintenance per flight hour.The F-22 also reportedly encountered a critical failure every 1.7 hours.[N 2] The F-22 had required maintenance every 0.97 flight hours in 2004. This improved to 3.22 flight hours per maintenance event in production Lot 6 aircraft.

The aircraft's radar-absorbing metallic skin is the principal cause of its maintenance troubles, with skin repairs accounting for more than half of the maintenance. Another source of maintenance problems is that many components require custom hand-fitting and are not interchangeable.[174] The canopy visibility has degraded more rapidly than expected, with refurbishments at 331 flight hours, on average, instead of the required 800 hours.[174] Pentagon officials respond that measuring flying costs for aircraft fleets that have not reached 100,000 flying hours is premature. They say improvements have been made since 2008, and the F-22s are on track to meet key performance parameters by 2010.[174]However, rain has caused "shorts and failures in sophisticated electrical components" when the Raptors were briefly posted to Guam.[180]

Each Raptor requires a month-long packaged maintenance plan (PMP) after every 300 flight hours.[181]