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1996 through April 1997.
Out of the 315 Predator missions tasked during that timeframe, weather and system cancellations kept
nearly two-thirds on the ground (60 percent). Of the remaining missions that were launched, slightly
under one half were subsequently aborted. These aborts were due to system (29 percent), weather (65
percent), and operational issues (6 percent) that included airspace conflicts, operator errors, and crew duty
limitations.
Data indicates that 38 missions (12 percent) were scrubbed due to system failures, an additional 18
system aborts (6 percent) that did not result in mission cancellation (due to launch of another aircraft or
weather hold), and other issues which kept the Predator on the ground 6 times (2 percent). Out of this
UAS ROADMAP 2005
APPENDIX H – RELIABILITY
Page H-6
total of 62 sorties affected by mission aborts or cancellations due to maintenance, operations, or human
errors, the systems’ failure breakout data is provided in Table H-2.
MQ-1B. The Predator transition into production led to some problems which affected aircraft reliability.
As the first ACTD program to transition to production, the Predator established the precedent, as well as
the lessons learned, for the transition process. First, nearly continuous deployment commitments since
March 1996 have delayed operational testing. Second, development of the ORD, usually produced early
in a program to guide system design, was not begun until after the ACTD ended (indicated by the N/A in
Table H-1) Third, additional challenges to system reliability were introduced, such as the addition of a
wing deicing system (glycol-weeping wings) as well as a redesigned control station for greater portability.
Since this rocky start, the Predator fleet has logged over 100,000 hours (as of October 2004) and has
“come of age” during Operations ENDURING FREEDOM and IRAQI FREEDOM. As a result of its
unorthodox transition process, however, Predator reliability issues were discovered and addressed during
operations around the world. Although the system still experiences reliability issues and aircraft losses,
its performance during these operations has been remarkably good when compared to those outlined in
the ORD.
The data in Table H-1 and H-2 represents all mission aborts (on the ground and in-flight) for all MQ-1B
systems between January 1997 and June 2002. The share of power/propulsion failure modes has doubled
in the MQ-1B compared to the MQ-1A. The Predator program office acknowledged that the engine is the
primary reliability issue.
The primary distinguisher between the MQ-1A and MQ-1B models is the Rotax 914 turbocharged engine,
which replaced the smaller Rotax 912 model, and was implemented primarily to increase the Predator’s
speed. With the new engine, a variable pitch propeller was also added. The data over this five-year
period indicates that the new variable pitch propeller accounted for 10 percent of all power/propulsion
aborts, while the engine made up nearly 70 percent. This is accompanied by a corresponding reduction in
flight control failures as well as a large decrease in malfunctions attributable to human errors and
operations and hardware on the ground. This does not necessarily mean that powerplant-related failures
have increased in the MQ-1B model, but that reliability improvements made in other areas
(communications) have made a comparatively greater impact on system reliability.
The significant decline in human and ground related errors (from 16 percent to 2 percent) is attributed to a
concerted training effort according to one Predator operator. Enhancements in situational awareness also
played a role in this positive trend. For example, periodic automated updates of the weather are supplied
to the control station. A VHF/UHF ARC-210 radio has also been added to provide voice relay capability
to the MQ-1B pilot, enabling direct, over the horizon communication with ATC authorities in the area of
flight. An APX-100 Identification, IFF/Selective Identification Feature (SIF) Mode 4 transponder was
added to further facilitate coordination with AWACS flight controllers. Air Force Portable Flight
Planning Software (PFPS), an offshoot of the Air Force Mission Support System (AFMSS), is another
tool defined in the Block 1 upgrade in which threat and mission planning information can now be passed
directly to the Predator system. The percentage of communications and flight control failures remained
virtually unchanged between the two models. Note: The RQ-1B became designated as the MQ-1B in
2002, after it acquired the ability to carry weapons.
MQ-9. To address certain reliability issues which arose during MQ-1B operations, the MQ-9 Predator
system, now denoted MQ-9A, is scheduled to undergo specific modifications from its predecessors
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