Page 65 - Australian Defence Magazine Feb-Mar 2023

FEBRUARY-MARCH 2023 | WWW.AUSTRALIANDEFENCE.COM.AU
AIRPOWER HAWK UPGRADE 65
LEFT: The RAAF’s Hawk Mk.127 Lead In Fighter Trainers are having their Rolls-Royce Adour Mk.871 engines replaced by the more powerful Adour Mk.951
RE-ENGINE PROGRAM
The first Adour Mk.951 engine arrived in Australia in De- cember and two others shortly thereafter. Modification of the first two aircraft for test and evaluation was completed in January 2023, and all flying aircraft will have 951 en- gines fitted by the end of 2024.
Changing engines takes three weeks, and two aircraft will be modified at the same time. Physically there’s no ex- ternal difference in configuration between the Mk.951 and the in-service Mk.871, and no new installation skills are required, according to Andrew Chapman, BAESA’s Direc- tor Aircraft Sustainment and Training.
“The 951 is a newer engine, it’s designed to more con- temporary standards and to design some of the new stan- dards back into the 871 would have meant almost bringing it up to 951 standards anyway,” he noted.
“The 951 provides up to 6,500lbs thrust against 6,000lbs so it will accel- erate a lot faster, it’s slightly more fuel efficient, it features a Full Authority Digital Engine Control (FADEC) and redesigned low- and high-pressure tur- bine sections, and it has a 4,000-hour overhaul rate compared to 2,000 hours.
“The main difference is the intro- duction of FADEC and the wiring that goes with that, and some mission systems change.”
“THE ACTUAL ANNUAL FLYING TIME FOR THE HAWK FLEET SINCE ITS ENTRY TO SERVICE IN 2001 HAD BEEN AROUND 6,500 HOURS”
BAESA pointed out that although the RAAF’s initial LIFT requirement had been for 9,000 flying hours per year, the actual annual flying time for the Hawk fleet since its en- try to service in 2001 had been around 6,500 hours – less than 200 hours per aircraft per year for an aircraft with a planned fatigue life of 10,000 hours.
Based on current usage and the outcome of a 50,000- hour structural test program on a Hawk fuselage undertak- en jointly with the Defence Science and Technology Group (DSTG), the fatigue life remaining in the Hawk airframe was sufficient to allow the aircraft to extend LIFT opera- tions not only beyond the initial planned withdrawal date of 2026 but also into the 2040s if required, the company emphasised at the time.
NIGEL PITTAWAY
Putting a Mk.951 in the RAAF’s
Hawk Mk.127s also makes them almost exactly the same aircraft as the Hawk T.2 fast jet trainers flown by the RAF, the latest version of the Hawk series.
Although Defence had acquired 39 Mk.871 engines for 33 airframes, experience had shown that purchasing 33
Mk.951s for 33 airframes would be sufficient to meet LIFT flying hour requirements.
“By the end of 2024 all of the Hawks being used by Air Force will have Mk. 951 engines in them,” Chapman said.
While problems had been experienced with the low-pres- sure turbine section of the Mk.871 these had been rectified as necessary, and there were no restrictions on the engine’s ongoing operation in the RAAF’s Hawk Fleet.
RAF EXPERIENCE
Ironically, it is faults in the low-pressure compressor of the successor Rolls-Royce/Safran Mk.951 engine, in this instance powering the RAF’s Hawk T.2, that seem likely to have an impact on UK fast jet training output over the next three years, the UK parliament was told in September by the then Minister of State for Defence Procurement.
“A number of engines have been temporarily removed from service whilst the Ministry of Defence supports a Rolls-Royce/Safran investigation into the root cause and rectification,” he said.