The Truth About an ‘Older’ U.S. Air Force Fleet

James Hasik

Security, United States

 It's the newer aircraft that are harder to maintain.

In Air Force Times this week, Jeff Schogol pulled some descriptive statistics from USAF records to report on “which aircraft are most mission-ready”. His list included the various types of attack, bomber, cargo (including gunship and electronic warfare), fighter, rescue helicopter, tilt-rotor, tanker, and drone aircraft currently flying in the Middle East. Mission-capable rates—the percentage of time that an airplane possibly needed for a mission actually was ready for a mission—varied over the past year from 92 percent for the MQ-1B Predator down to 47 percent for the B-1B Lancer. What the table didn’t show was how those rates related to his other two descriptors: the size of the USAF’s fleet of that aircraft type, and the average age of the aircraft in that fleet. A common refrain holds that having more of any single type of aircraft makes maintenance more scale-efficient, and that newer aircraft are easier to maintain than older aircraft. Ceteris paribus, both are almost unassailably true. For the USAF, however, neither relationship is actually putting rubber on the ramp.

I thought that the graphic artist’s straightforward table could be usefully made into something more analytically revealing, so I built a bubble chart of fleet sizes atop a scatter plot of fleet readiness versus average aircraft age. In the embedded figure, the bubbles and the attached numbers represent how many of each aircraft type the USAF has in its fleet. (To match the numbers to the aircraft type, see Schogol’s article.) The chart further displays the average age of that fleet on the horizontal axis, and the mission-capable rate throughout 2015 on the vertical axis. In this analysis, I thus take fleet age and fleet size as independent variables that could logically affect the dependent variable of fleet mission-capable rate. That seems reasonable.