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Last Updated: Mon Jan 27 11:18:09 UTC 2014

JSF F-35 Program: How Many Miles Does an F-35A Go On a Tankful of Gas?

Air Power Australia - Australia's Independent Defence Think Tank

Air Power Australia NOTAM

  6th April, 2009

WGCDR Chris Mills, AM, BSc, MSc(AFIT), RAAF (Retd)

Contacts: Peter Goon
Carlo Kopp

Mob: 0419-806-476 Mob: 0437-478-224

Aerial refuelling of F-35A AA-1 from KC-135R tanker (US DoD image)

If you live in the boondocks where it is a long way between gas stations, then when you purchase a new SUV, one of the Key Performance Parameters (KPPs) you ask the salesman is how far a tank of gas will take you.  Being out of fuel in the middle of Death Valley with the midday sun blazing down is no picnic.
And so it is with aircraft, especially air combat aircraft that must fly to a target area, engage the enemy, then fly home.  If you have the range to deliver a war-load a long way, then you keep the bad guys away from your AWACs and tankers, or better still, fly the whole mission without vulnerable Low Density / High Demand (LD/HD) support.
In August 2002, Colonel Dwyer Dennis of the Joint Strike Fighter Project Office was briefing his buddies ‘down-under’.  This was in the halcyon days when the JSF project was on-track, on-time and on-cost.  The role of KPPs was discussed, and the Colonel noted:

“I'm going to talk a little bit about what we call KPPs, or Key
Performance Parameters. The key performance parameters on a program are those requirements that are the make or break on a program.  You miss a KPP and your program is subject to cancellation or major rework. …….
One thing that I didn't talk about earlier, …., is that because this is a stealth aircraft it has internal weapon bays and to make it stealth the weapons have to be internal in a low-observable mode, so that makes the plane pretty thick and so that gives you a lot of room for fuel. So these aircraft have tremendous range.
The CV variant is outward to almost 700 - the Air Force I think about 590.
So very significant range. That's no external fuel tanks, just the internal mission fuel. To give you an idea of the internal fuels - 18,000-plus for the CTOL, 13,000 for the STOVL and over 19,000 pounds for the CV aircraft.”

he JSF has over 430 KPPs designated, all of which are ‘project critical’, with the radius of action being one of these.  If the JSF fails to meet or exceed that KPP, then, according to the Colonel, the consequences for the JSF project would be extremely serious, as in ‘project cancellation’ or ‘major rework’.
And so it should be!  To do otherwise is, at best, just silly.
Why do intelligent buyers specify KPPs? 
Well, the operations research defines what capabilities are required, and the KPPs are then set as the criteria which decide on a ‘buy or no-buy’ decision.  Should an aircraft manufacturer achieve the designated KPPs?  You bet, otherwise any piece of rubbish will do, and there will be failures, some spectacular, when you take an air combat aircraft into a shooting war.
When should KPPs be tested? 
An intelligent buyer will demand that achievement of a KPP should be demonstrated at the earliest possible time.  If the aircraft fails to meet the designated KPP, then there is the greatest possible time to redesign the aircraft, or if it cannot be successfully redesigned, scrap the project and seek alternative way of meeting the capability requirements.
Who should be accountable for testing JSF KPPs? 
Commonsense suggests that it should be the Joint Strike Fighter Project Office since they define their ‘mission statement’ as:
The Joint Strike Fighter (JSF) Program, formerly the Joint Advanced Strike Technology (JAST) Program, is the Department of Defense's focal point for defining affordable next generation strike aircraft weapon systems for the Navy, Air Force, Marines, and our allies. (Refer http://www.jsf.mil/program/).
This is a curious and worrying statement, also from the mission statement:
“The focus of the program is affordability -- reducing the development cost, production cost, and cost of ownership of the JSF family of aircraft.”
The focus is ‘affordability’?  Should not the focus be ‘effectiveness in future air combat?
There is also this key question:  is the JSFPO buying or selling the F-35 Lightning II? 
While many naturally assume that the ‘Purchasing (i.e. Program) Office’ is charged with conducting Caveat Emptor activities on behalf of the US Department of Defence and the US’s Allies, many of the recent statements of the JSFPO’s Program Executive Officer sound distinctly like the JSFPO is selling the aircraft rather than buying it.  And if the JSFPO and the PEO are not conducting Caveat Emptor activities like testing achievement of KPPs, then who is?
Notwithstanding, we seem to be at the point where the JSF can demonstrate a ‘mission critical’ KPP like the un-refuelled combat radius of action.  This KPP has been set at a minimum of 590 nautical miles, or 1180 nautical miles in a straight line.  The combat load should be defined by the KPP – perhaps 2 x 2,000 lb JDAM, 2 x AIM-120 or 2 x AIM-9X.  The fuel reserves should also be defined – perhaps 30 minutes of useable fuel, that being in excess of the fuel required to cool the JSF’s systems.
The JSF recently demonstrated its ability to fly a sortie of this distance – the repositioning of aircraft AA-1 from Ft Worth NAS in Texas to Edwards Air Force Base in California – a great-circle distance of 1041 nautical miles.  Unfortunately, testing the un-refuelled combat radius KPP was not possible on this flight because the JSF was accompanied by a Tanker, and AA-1 had a couple of drinks along the way.
The Development Test and Evaluation mission profile for the un-refuelled range KPP is easy to set-up.  Fill the internal fuel tanks of a CTOL JSF to the maximum capacity; load the aircraft with a representative weapon configuration; then, with a representative pilot at the controls, fly the designated USAF sortie profile. 
Total planned flight distance should be at least 1180 nautical miles.  Lockheed Martin might like to use a ‘fly-out  fly-back track, so that the test pilot can monitor fuel burn and adjust the distance flown – either increasing or decreasing distance flown to arrive overhead the destination airfield with 30 minutes holding.  On shut-down, the JSF would be refuelled to ‘full tanks’ so that the fuel burn along the way would be exactly established.  A few sums, and the un-refuelled range could be shown to be either a ‘pass’ or a ‘fail’ against the 590 nautical mile KPP.
Of course, the whole exercise should be monitored by independent agencies, perhaps key customers such as the USAF and US’s Allies interested in purchasing the JSF, and the measurement process assisted by the Defence Science Board and the Government Accountability Office.  These Agencies would confirm that the test JSF was fully fuelled, that the claimed distance flown was accurate, the stated fuel burn was exact and the allowance for wind along the way a true measure, and, importantly, that the required fuel reserves were preserved, including fuel required for systems cooling.  They would then independently calculate the un-refuelled combat range.
The JSF should be accompanied by an escort aircraft to ensure both aircraft stay on track; to independently measure the distance over the ground; measure wind aloft along the flight path; and, to render assistance in the event of an emergency.

Likelihood Consequence
Almost certain H H E E E
Likely M H H E E
Moderate L M H E E
Unlikely L L M H E
Rare L L M H H

E– Extreme level of risk (Immediate action required by Executive and Directing Governance levels, i.e. do not proceed with activity until this level of risk is reduced)
H– High level of risk (Executive Management attention required)
M– Moderate level of risk (Able to delegate to Implementation Management Level with ongoing Executive Management oversight)
L– Low level of risk (Able to be managed through routine procedures)

Table 1: Risk assessment process and associated template of AS/NZS 4360:2004 (P.A. Goon).

To add interest, the JSF might be accompanied by an F-15E Strike Eagle carrying the same test weapons load:  2 x 2,000 lb JDAM, 2 x AIM-120 or 2 x AIM-9X.  My flight manual for the Strike Eagle is out-of-date as it only has performance figures for the old F100-PW-200 engines.  Even so, with 30 minutes of holding at the destination, retaining all stores and with Lantirn Navigation and Targeting pods fitted, the combat radius is 945 nautical miles or 1,890 nautical miles in a straight line.  Escorting the JSF will force the F-15E to fly a slower, lower, sub-optimal flight profile, but as this aircraft has ‘fuel to burn’, it should have no trouble providing escort to the JSF on this important test run.
Combat radius of action is rightly a critical Key Performance Parameter.  Failure to meet or exceed this KPP is also rightly a critical element of a go no-go decision for the JSF program, refer Table 1. 

The flight of JSF AA-1 from Ft Worth to Edwards Air Force Base
was a proving flight that demonstrated there are no impediments to the critical un-refuelled range KPP being able to be demonstrated in the very near future.
So, please Mr Lockheed Martin, how many miles do we get from a tankful of gas in a JSF?

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