The F-35B Short Take Off and Vertical Landing variant

by Karim Toure

The Department of Defense announced Friday, May 13th 2011 a massive order for 36 Pratt & Whitney F135 engines powering the F-35 Lightning II Joint Strike Fighter. The monetary award worth $910M includes delivery, logistics and engineering support services for:

-10 Conventional Take Off and Landing (CTOL) propulsion systems along with 2 spare engines and parts for the U.S. Air Force F-35A

-16 Short Take Off and Vertical Landing (STOVL) F-35B propulsion systems also with 2 spare engines and supporting equipment destined for the Department of the Navy (United States Marine Corps)

-4 Carrier Variant (CV) F-35C propulsion systems plus 1 spare engine going to the U.S. Navy

-1 Navy Short Take Off and Vertical Landing STOVL F-35B propulsion system funded as Foreign Military Sales contract for the United Kingdom.

This latest 36-engines funding package was expected last year to complement a November 2010 $3.5B procurement contract for 31 Lot IV Low Rate Initial Production F-35 airframes, 10 of which being F-35A Conventional Take-Off and Landing CTOL aircraft for the U.S. Air Force, 16 F-35B Short Take-Off Vertical Landing (STOVL) aircraft for the U.S. Marine Corps, 1 F-35B STOVL aircraft for the United Kingdom Royal Navy along with 4 F-35C Carrier Variant (CV) aircraft for the U.S. Navy. The one-year delay in the order Illustrates some of the schedule postponements and cost overruns that have challenged the JSF development program since System Development and Demonstration (SDD) phase began in 200. Recent media attention echoed one of the program’s cost escalation dilemma which resulted in the F-136 Alternate Engine Program being canceled on April 25th 2011 (on March 24th 2011, a stop work order was issued to the General Electric / Rolls Royce Fighter Engine Team by the Defense Department followed by an official contract termination on April 25th 2011 in an attempt to eliminate a $1M per day cost to the program).

We have thus found opportune to review publicly available documents relating to the progress made in the JSF program -particularly since flight testing gathered more momentum in 2010- in order to better capture the US government efforts to keep the program funded as it is critical to ‘recapitalizing’ the entire US tactical fighter force across 3 services as well as the air arms of 8 other nations. The Government Accounting Office has conducted independent audits whose latest findings have ascertained that the program should continue being funded despite grievous budgetary constrains. While the Selected Acquisition Report (SAR) from Defense Acquisition Management Information Retrieval (DAMIR) highlighted some of the aircraft shortcomings as uncovered during flight testing in 2010. We will see that 2010 turned out to be a pivotal year for the program as serious restructuring efforts were put in place. The essence of those findings and the key recommendations issued are summarized further.

The F-35 Joint Strike Fighter – Lightning II

The F-35 Joint Strike Fighter christened the Lightning II implements 5th generation combat aircraft capabilities that will exploit low-observable technologies, defensive avionics systems, advanced sensors ‘fusion’, internal and external weapons capacity, enhanced prognostic maintenance capability throughout the 21th century replacing legacy fighter aircraft. For instance the F-35A Conventional Takeoff and Landing CTOL variant is a stealthy multi role, air-to-ground-capable aircraft replacing the F-16 Falcon and A-10 Warthog and complementing the F-22 Raptor. The F-35B Short Take Off and Vertical Landing STOVL variant replaces the strike fighter AV-8B Harrier II and multi role F/A-18A/C/D for the US Marine Corps and the AV-8 ‘Harrier’ currently with the Italian Navy. The F-35C aircraft Carrier Variant CV is a Navy multi role stealthy strike fighter aircraft complementing the F/A-18E/F and replacing the Sea Harrier and GR7 for the United Kingdom Royal Navy and Air Force. Participating to this group are fighter forces of 8 nations including Canada, The Netherlands, Italy, Turkey, Australia, UK, Denmark and Norway having contributed approximately $5.1 billion and technological firms for the program industrial base. Lately the total planned US investment in the program has fluctuated towards $382 billion for the development and acquisition of 2,457 aircraft through 2035 putting additional budgetary strains in times of scarce financial resources.

I. February 2010 Program restructuring

1. Development Program from 2001 to 2009

The initiative to provide America and its allies with the 5th generation ‘low-cost’ fighter aircraft (one of the main requirement to be a viable replacement candidate for the large number of F-16 produced) began in November 1996. After a 5 years competition, the main contract winner Lockheed Martin began System Development and Demonstration (SDD) in October 2001. The Pratt & Whitney F-135 was the primary engine retained for the aircraft (accompanied by the now canceled F-136 alternate engine). Initial 2001 plans requesting funding for the development and procurement of up to 2866 aircraft were curtailed by March 2004 when the program underwent a first Technical Baseline Review re-alignment. This was followed quickly by another in 2007. The extended time delays required to overcome various technical and design challenges propagated into additional cost which at some point led to the US Navy and US Marines reducing their orders by 409 aircraft to the current level of 2,457 jets. The new baseline set in 2007 compounding more schedule slips to cost growth, extended the procurement period by 7 years to 2034 while negatively impacting annual quantities of procured aircraft. In terms of program funding, the initial October 2001 projected total cost of $233 billions (for both development and procurement funding) was re-evaluated to $244 billions in December 2003. The 2007 approved baseline budgeted $278.5 billions. By 2009 a state of crisis had erupted. A comprehensive review was commissioned by he Department of Defense involving 3 independent review teams set up for the effort: a Joint Estimating Team (JET) analyzed program execution and resource requirements, an Independent Manufacturing Review Team (IMRT) assessed contractor manufacturing capabilities and production rates and a Joint Assessment Team (JAT) reviewed engine costs. Their three immediate recommendations were the addition of $2.8 billion into development funding, the extension of the flight testing period by 13 months at an accelerated pace with the addition of 1 extra test aircraft and 3 production aircraft and a further reduction of the number of aircraft being procured in the near term to 122 units.

2. The audit conducted by GAO

In addition the Government Accounting Office conducted a performance audit from May 2010 to March 2011 in order to address progress established through prior assessments, program changes in cost and scheduling, issues with design elements and manufacturing and overall technical challenges. GAO auditors thoroughly reviewed Department of Defense internally documented restructuring actions , repercussions to the program execution, manufacturers-provided data as well as test plans.

3. Breach of Nunn-McCurdy in 2010

With the initial October 2001 total program cost forecast of $233 billions being re-evaluated to $244 billions in December 2003, the 2007 approved baseline budgeted also grew to $278.5 billions. With up-front cost being incurred by the initial 2010 restructuring program, the program hit $328.3 billions by April 2010. Already by March 2010 a Breach of Nunn-McCurdy statutes on cost growth threshold was noticed prompting notification to Congress, program reassessment and new certification to Congress were mandated in June 2010. Generally Critical Cost Growth Thresholds or Nunn-McCurdy are breached when a program procurement unit cost or acquisition unit cost grows by at least 25% over the Current Baseline Estimate or at least 50% over the Original Baseline. In the F-35 program, by the time Nunn-McNUrdy was breached the program had reached $382.5 billions. At that point the unit cost accordingly evaluated at $69 millions in 2001, $82 millions in 2003, $95 millions in 2007, $114 millions in April 2010 neared $133 million during June 2010 reporting to congress.

According to the Selected Acquisition Report the Nunn-McCurdy breach was at a high margin of 78.23% for Program Acquisition Unit Cost PAUC and 80.66% for the Average Procurement Unit Cost APUC against the 2001 baseline. In comparison to the 2007 baseline the threshold numbers were 27.34% in acquisition unit cost and 31.23% in procurement cost.

4. Restructuring costs are already adding to development cost at the expenses of procurement funding.

In January 2011, the Secretary of Defense announced additional development cost increases and further changes required for the successful completion of the program restructuring.

The restructuring major drawbacks became apparent: the higher up-front development costs would translate into fewer aircraft received initially, as well as training delays and extended times for testing and delivering the capabilities required by the warfighter. This situation is further contributing to the aircraft being anticipated by some to cost almost double its original unit procurement cost. Some data even suggest that it will be costlier to operate and maintain than the aircraft it aims at replacing.

The Fiscal Year 2012 defense budget will address restructuring cost issues by increasing funding by $7.7 billion while decreasing procurement by $8.4 billion. The new Acquisition Program Baseline APB review expected late 2011 is likely to also document the higher cost of restructuring and the new schedules slips. In all these effects may cause the program to enter Full Rate Production no earlier than 2018, 5 years later than the current baseline program (delivered in 2007) projected.

II. Secretary of Defense Directives issued January 2011

1. Program Restructuring

The Technical Baseline Review undertaken post Nunn-McNurdy led the Secretary of Defense to order more changes to the program in January 2011; according to the Selected Acquisition Report the Technical Baseline Review TBR commissioned before November 2010 had gathered up to “120 subject matter experts from the Aeronautical Systems Center, Naval Air Systems Command, and Office of the Secretary of Defense”. At the same time a Manufacturing Review Team MRT conducted a separate audit of the contractor’s ability to produce aircraft and their ability to ramp up production efforts. ..In January 2011, the Secretary of Defense announced program decisions hat conformed almost entirely to the recommendations issued by the TBR;

-current annual funding levels for development and procurement maintained through Fiscal Year 2012-2016 and addition of $4.6B to the System Development and Demonstration whose duration is extending to 2018,

-separating testing of the Short Take Off and Vertical Landing variant from that of the Carrier Variant and Conventional Take Off and Landing variant, placing the STOVL in 2-year probation.

The Department of Defense is providing monthly Service Acquisition Executive reviews on F-35 airframe and propulsion performance during System Development and Demonstration. The reviews emphasize cost/affordability, risk and schedule. For instance the F-35B weight growth has become a most critical engineering-related issue (Airframe Technical Performance Measurements metrics assess the reliability, combat radius and gross weight).

-The overall production plan of the F-35 will see a reduction of the aircraft buys by 124 jets over the Future Years Defense Plan.

-Conducting a review of contractor’s software development, integration and test process. The Department of Defense is facing with the main task of ensuring the delivery of Block 3 (full warfighting software integration) capability on aircraft through the end of the SDD phase.

The Secretary also announced that the program was completing a Technology Readiness Assessment TRA on the Helmet Mounted Display.

The additional $4.6 billion that the development program received brought total project funding to $56.4 billion (it was $50.2 billions in April 2010 and $51.8 billions at June 2010 Nunn-McCurdy certification to congress). Yet this 26% increase from the 2007 Baseline projection of $44.8 billions (it is 64% against the original baseline of $34.4 billions provided in 2001) led to 124 aircraft being cut from initial procurement on top of the 122 cut in February 2010 totaling 226 aircraft deliveries canceled through 2016.

2. The special case of the STOVL variant

Flight testing for the overweight Short Take Off and Vertical Landing variant would proceed independently of the other variants and fewer aircraft would be built 3 in 2011, 6 each in 2012 and 2013 (15 aircraft instead of 37 planned) until the design issues that led to the aircraft extra weight and performance issues. This particular application presents additional complexity in comparison to both Conventional and Carrier as the lift fan located aft of the cockpit is sandwiched between the two lateral air intakes. Uses a drive-shaft to sustain coupling and rotation with the actual turbofan located further to the rear. Moreover the engine steerable nozzle which can be rotated downward provides additional lift and symmetrical balance with the lift. and cost ultimately causing 2-year probation period imposed by the secretary to engineer solutions, assess impacts, and inform on how to proceed for the future.

3. Uncertainties regarding the upcoming 2011 re-baseline (postponed from November 2010)

Sustaining overall program funding to current level will impact defense budget in the amount of $11 billion per year for the next two years. Uncertainties regarding the schedule extensions has already led the US Navy to consider acquiring more F18E/-F Super Hornet to maintain readiness. The Israeli Air Force has floated the idea of sourcing F-15 while awaiting delivery of 20 F-35s.International partners have provided $5 billion already and seek 223 aircraft worth $24.1 billion (730 initial purchase were expected by DoD), the lesser quantity resulting in higher unit cost for all including participants in the program, including the US Navy and US Air Force.

The revised 2012-2016 budget for Development and Procurement is likely to provide $61.5 billions ($10.8 in development funding and $50.7 billions in procurement), allowing 325 aircraft to be acquired. In this scheme the USAF would receive 203 F-35A, US Navy 72 F-35C and the US Marines Corps 50 F-35B. For cost analysts still busy planning for the 2017-2035 period, uncertainties and risk of increase for future costs when deferring purchases remain elevated; inflation, additional labor as well as reduced number of orders labor will drive future unit prices higher. Use of production aircraft for training will also limit training and delay deliveries of full capabilities to the warfighter. At this juncture it would not be unrealistic to envision Full Rate Production to 2018 5 years later than programed in the 2007 baseline.


III. The Flight Testing Program

The latest Selected Acquisition Report identifies 15 aircraft actually delivered to the SDD flight test program as of February 15th 2011 (including 5 ground tests aircraft). The 800 flight hours that have been accomplished were conducted by 9 System Development and Demonstration aircraft AF-1, AF-2, AF-3, AF-4, BF-1, BF-2, BF-3, BF-4 and CF-1 which flew for the first time in June 2010. The F-135 engine has completed an additional 12,136 hours of testing via ground-test engines. General conclusion was that the Conventional Take Off and Landing variant at Edwards AFB California exceeded performance estimates. At Patuxent River Naval Air Station, The Carrier Variant performed satisfactorily but the STOVL substantially underperformed as previously mentioned with obvious re-engineering implications coming in the near future. Additional issues for the program were the slow pace of testing in demonstrating that the aircraft will work in its intended environment. Substituting ground testing for flight testing has been near impossible to accomplish as ground testing labs and simulation models are not accredited or verified (only 3 of 32 were accredited). The scoring system put in place to assess the progress of the flight testing phase requires 50,000 points to be reached reached. By the end of 2010 a 10% progress (5,000) had been achieved. Only one fifth (1/5) of planned flight test planned in the 2007 baseline actually took place in 2010 at a rate of 2 to 8 flight tests per month compared to the target rate of 12 flight tests per month.

1. Stabilizing the designs

The JSF has still not fully demonstrated a stable design and mature manufacturing processes as it enters 5th year of production (plus 9 years of SDD): engineering changes have occurred at higher than expected rates long after Critical Design Reviews were completed in 2007 and 2006 for the 3 variants and well into procurement. Since 2007 the program has produced more than 20,000 more engineering drawings (50% increase, 5 times the norm) with 10,000 more expected by January 2016.

Five design concerns have emerged each likely to introduce further design changes before the end of the SDD phase:

-the lift system for the Short Take Off and Vertical Landing variant expects a mature redesign of lift fan and drive shaft in spring 2011

-fatigue cracks were discovered in a major bulkhead of the STOVL while undergoing 1,500 hours of ground-based durability testing (less than 1/10 of the total hours planned for fatigue tests)

-wing tip vortex are visible to the naked eye due to water condensation losing the aircraft stealth

-outer mold lines have not adhered to the characteristically high tolerance that have been specified for the aircraft to maintain low radar observability. This issue has varied according to suppliers employing different processes.

Building the jet proves more labor intensive than planned, casting doubt in the manufacturers processes and ability to ramp up production to the planned 20 aircraft per month. Engines, it seems will also be difficult to manufacture at higher annual rates.

2. Defects and failures

The aircraft scored poorly in maintainability; initial revue of data measurements for Mean flying hours before failure have indicated design and manufacturing defects and excessive components failure. The Conventional Take Off and Landing variant has achieved a 1.8 mean flight hours before failure against the planned 2.9. The ultimate goal for the aircraft at maturity being 6.0. The Short Take Off and Vertical Landing fared worse with a demonstrated 0.4 mean flight hours before failure (the STOL aircraft intermediate goal for the test plans is 1.9 and 4.0 at maturity). The low monthly rate of flight test carried out each month has also been directly attributed to excessive components failure with design and manufacturing defects causing prolonged maintenance periods

3. Software and Integration

According to GAO Software development fell behind with most complex tasks being pushed ahead. The audit recognizes that three quarters of the code have been written and integrated although not tested. The program’s software generation will integrated complex real-time interfacing of sensor ‘fusion’, weapons and fire control, maintenance and diagnostics, and propulsion and various actuated controls. The effort implements 8 times more software lines of code than found on the F/A18E/F and 4 times more than the F-22. The last available officials figure for 2009 was 40% integrated. Software growth was 40% at preliminary design review, 13% after the critical design review. Recent programs saw 30 to 100% growth. The Selected Acquisition Report specifies that the initial limited release of Block 1 software was flown for the first time in November 2010 with Block I capability being implemented in software code at 81% (20M out of 24M software line of code). The road to Block 3.0 full warfighting capability scheduled for development in 2011-2014 has been charted through implementing the following blocks: Block 0.1 (flight sciences 2006-2007), Block 0.5 (initial mission systems architecture 2008-2010), Block 1.0 (initial training capability 2008-2011), Block 2.0 (initial warfighter capability 2010-2013) and Block 3.0 (full warfighting capability 2011-2014).

The JSF may not become the 5th generation tactical aircraft most likely replacement for the widely used F-16 on account of its unit price and high cost of maintenance and operation with unit cost in 2012-2016 at no less than $141 million a piece for the F-35A, $183 million for the F-35B and $180 million for the F-35C -after- development costs being factored in. The $60 billion mark funded to date is about near with another $11-$14 billion being the likely additional increment required each year until 2035 to cover for the total program cost that will be above $382 billion (upwards of $400 billion is not far fetched). However the political will behind the project will remain strong with the understanding that the aircraft is key to US Defense Strategy in the 21st Century. On the ground of pure technological advances and performance capabilities we are convinced that the aircraft being more versatile and somewhat still cheaper than the F-22 is extremely appealing. When technology matures and main contractors become comfortable expending the mission envelopes requirements of the aircraft (around 2025), the F-35 will be the dominant platform for modern air combat operations.


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