F-35 Requiring Up to 50 Maintenance Hours per Flight Hour (F-22

Navair Sees F-35 Requiring Up to 50 Maintenance Hours per Flight Hour
(Source: Defense-Aerospace.com; posted Dec 05, 2016)
By Giovanni de Briganti
http://www.defense-aerospace.com/articles-view/feature/5/179243/navair-projects-f_35-to-need-50-maintenance-hours-per-flight-hour.html

PARIS — Four years into their operational career, F-35 fighters are
expected to require between 41.75 and 50.1 maintenance man-hours (MMH) per
flight hours, or about three times as many as most fighter aircraft
currently operated by Western air forces.

This extremely high MMH to flight hour ratio is extrapolated from a Dec. 01
solicitation filed by the US Naval Air Systems Command, and which states
that the world-wide in-service fleet of F-35s will require 17 million
man-hours of maintenance and sustainment in FY 2018 and FY 2019.

Navair’s “Sources Sought” solicitation, posted on the Federal Business
Opportunities (FBO) website, and whose most significant excerpts are
reproduced at bottom, estimates that the F-35 fleet will include 597
aircraft at the end of FY18 and 760 aircraft at the end of FY19 (September
2019).

The US Marine Corps declared Initial Operational Capability for its F-35B in
July 2015, and the US Air Force followed for its F-35A in August 2016, so at
this time the aircraft will have been in service for three to four years,
depending on the version.

The number of aircraft in service — 597 by late FY18 and (597 + 163 = 760)
by late FY19) imply that the total requested 17 million man-hours of support
equates to 12,527 per aircraft per year, or about 1,043 hours per aircraft
per month.

Given that the average F-35 combat aircraft is expected to fly 250 hours per
year, simple arithmetic shows that Navair expects the F-35 to require, on
average, 50.1 maintenance man-hours per flight hour – it would have required
41.75 MMH if it flew 300 flight hours, as originally planned.

The US Air Force originally planned to fly its F-35s 300 FH per Primary
Aircraft Inventory per year. Subsequently, it reduced the F-35A flying hours
from 300 to 250 FH per PAI.

That is several times as many maintenance hours as current front-line fast
jet fighter operated by the US services, and also well over that of the F-22
Raptor, which “is required to achieve 12.0 direct maintenance man-hours per
flight hour (DMMH/FH) at system maturity, which is defined to be when the
F-22 fleet has accumulated 100,000 flight hours,” according to a US Air
Force Association response to a story by the Washington Post.

Facts: The F-22 is required to achieve In 2008 the F-22 achieved 18.1
DMMH/FH which then improved to 10.5 DMMH/FH in 2009. It’s important to
recognize this metric is to be met at system maturity, which is projected to
occur in late 2010. So the F-22 is better than the requirement well before
maturity.

Clearly, in FY2018 the F-35 will have only been in “operational” service for
three or four years (IOC in mid-2015 and mid-2016), and so still a long way
from maturity, but such a high number of maintenance hours will explode
operating costs for its operators, who were long told the F-35 would be
afford able to buy and to operate.

(ends)