In late 2018 the U.S. Secretary of Defense ordered the air force and navy to raise the readiness rate (percentage of available aircraft able to do their job) to 80 percent for several key combat aircraft and get it done during fiscal 2019 (which ended September 30, 2019). The aircraft involved were the air force F-16, F-22 and F-35 as well as the late model navy F-18s (F-18E/F and EA-18G). Only the navy made it, hitting 80 percent in September 2019. The navy had the hardest job because when the order was given, these F-18s had a readiness rate of 50 percent. Even though they came up short, some of the air force aircraft made remarkable progress, The F-16 went from 70 to 75 percent while the F-22 went from 52 percent to 68 percent and the F-35 went from 50 percent to 74 percent. The air force pointed out that the average readiness of all these aircraft increased by 16 percent and those selected to be sent overseas within 30 days of an emergency increased readiness by 35 percent. The navy had a similar policy, with air wings assigned to a carrier being brought up to a higher readiness rate than those air wings operating from land bases until a carrier completed maintenance, upgrades and other work needed before the carrier and its air wing went off on another six months (or more) at sea.
Overall the “80 percent challenge” did have a positive effect because when the Secretary of Defense ordered the effort, readiness rates had been falling for over a decade. There were reasons for that. Since 2001 air force and navy aircraft have been largely operating under wartime conditions. American military aircraft readiness rates have traditionally been high compared to all other major air forces. But age and two decades of heavy use has taken its toll. The workload for maintenance personnel is higher, while budgets for maintenance were not keeping up. This has reduced readiness rates noticeably in the last few years, but compared to a decade ago the air force was doing rather well. Readiness rates or the percentage of your aircraft that are “mission-capable” varies by aircraft type and technology an aircraft is based on. Age is important but has less to do with it than you might think.
For example, the readiness rates for fighters in late 2016 (rate from a decade earlier in parenthesis, NA means not applicable because the aircraft was not in service back then); F-15C, 71.5 (71) percent, F-15E, 71.2 (72.5) percent, F-16C, 70 (75.4) percent and recently hit 75 percent, F-22A, 51.7 (60.9) percent and recently hit 68 percent, A-10, 72.5 (70.5) percent, F-35A, 49.6 (NA) percent and recently hit 74.5 percent.
The F-22 rate was higher a decade ago, partly because it had overcome the problems of being a new aircraft. But the problem of high maintenance costs and lack of durability led to a slide from a high of 65 percent readiness in 2014 to the low rate in 2018. The many stealth features of this aircraft required special, time consuming and expensive attention, and provided more items that can break. The F-35A was not yet in service a decade ago so this new stealth fighters is where the F-22 was back then. The F-35 was designed to overcome the readiness problems of the F-22.
For bombers, the rates are; B-1B, 51.7 (43.8) percent, B-2A, 60.7 (54.9) percent, B-52H, 69.3 (74.6) percent. A decade ago the B-1B was cursed with additional components (especially hydraulics) that enabled it to fly fast and low. That capability was not used anymore, but the equipment is still there, and when any of it broke, the aircraft doesn't fly. The unused equipment was eventually removed, solving a lot of readiness problems. The air force recently decided to retire all the B-1Bs. The B-2 has lots of stealth stuff but the air force has overcome many of its unique maintenance problems. Meanwhile, the ancient, but relatively simple, B-52 had the highest readiness rate and still is the cheapest to operate. But the B-52s were built in the 1960s and despite ongoing upgrades, age is catching up with the elderly but reliable heavy bomber. Heavy bombers, in general, have, because of smart bombs, been heavily used since 2001. The B-52 will remain in service until at least 2040.
Transports also are relatively simple in terms of tech, and their readiness rates show this; C-130E, NA (76.7) percent, C-130H, 68.3 (73.8) percent, C-130J, 76.7 (82.3) percent, C-17A, 82.6 (84.4) percent, C-5, 62.6 (52.7) percent, CV-22, 59.4 (54.3) percent. The lowest rates are either the result of age (the C-5) or lots of tech (the tilt-rotor CV-22).
Electronic warfare aircraft, despite all the complex electronics carried, are basically transports full of electronics and operators. E-3, 69 (71.6) percent (AWACS), E-8, 66.9 (81.1) percent (JSTARS), MC-130H, 84.3 (70.6) percent, MC-130J, 79.3 (65.2) percent,
Aerial tankers are transports, and quite elderly as a result; KC-10A, 79.7 (74.8) percent, KC-135R, 73 (81.1) percent, KC-135T, 73.8 (80.4) percent. The readiness rate for these old, and heavily used, aircraft does not reflect the large number (up to 20 percent) of aircraft that are pulled for major rebuilds. Thus the most decrepit tankers are not counted, keeping the readiness of aircraft in squadrons at a high rate. While the tankers are being replaced with a new model, that KC-46 aircraft is behind schedule because of quality control issues. Not a good sign because the new tanker is based on a proven and widely used Boeing 767 commercial transport.
UAVs are simple aircraft, and their high readiness rate reflects this; MQ-1B, 73.7 (93) percent, MQ-9A, 90.2 (91.9) percent, RQ-4B, 73.7 (41.6) percent. One exception is the RQ-4 Global Hawk, which is a jet-propelled, trans-oceanic aircraft. It is a much more complex beast and has long had more maintenance problems. The air force is not happy with this and 24 older RQ-4s are being retired with all Global Hawks likely to be phased out after that. The MQ-1 is officially retired and only a few remain. The MQ-9 is the main UAV, with over 300 in service. That’s more than many types of manned aircraft. UAVs are still seen as the future and by removing the crew, and all the gear needed to sustain them, aircraft become easier and cheaper to maintain.
Trainers are simple aircraft, and their readiness rates reflect this; T-1A, 58.9 (79.7) percent, T-38A, 72.6 (80.4) percent, T-6A, 66 (80.3) percent.
The air force only has one type of strategic (long distance, high altitude) recon aircraft. More than most jets, the U-2 is a powered glider. It is old (in design), simple and very reliable. U-2, 76.9 (81.2) percent
The air force doesn't have many helicopters, and they are army models. The army designs its helicopters for easy maintenance and heavy use. HH-60G, 70.7 (74.6) percent (search and rescue), UH-1N, 83.6 (80.9) percent (transport),
There are two other issues that remain unresolved. One is the age of combat aircraft. The F-35 was late arriving in large numbers and the F-16s and F-15s they were to replace are still in service. As aircraft age, maintenance costs rise and the air force budget is not rising to deal with that. As a result readiness rates for these older aircraft have been falling during the last few years. At the same time, most of the aircraft have benefitted from tech upgrades. Not just new electronics but also components made of new materials. Despite all that, age and increasing maintenance costs eventually prevail in the form of lower readiness rates. However, with enough money and motivation, the older aircraft can still maintain high readiness rates. Sometimes that additional cost is found to be cheaper than developing and building a new aircraft.