Tactical aircraft transition choices loom for U.S. Navy
The U.S. Navy faces a decision regarding its future aircraft fleet planning: How will it manage the transition of its tactical aircraft procurement from the current /F Super Hornet and Growler to the Joint Strike Fighter while retaining the resources necessary to buy a new carrier-launched reconnaissance-strike UAV?
The service must also hedge against further delays with the F-35C, which has not yet demonstrated its ability to land on a carrier. Trials are now due for 2014, following two redesigns of the arrester hook. The Navy has not elected to declare initial operational capability (IOC) with interim Block 3I software and will wait for Block 3F, which is acknowledged to have higher schedule risk. It also plans to buy a minimal number of F-35B/Cs through 2015 (the 2017 delivery year) and then increase to 18 airframes in 2016 and 28 in 2017, attaining its sustained rate of 40 aircraft in 2018.
The service is not asking for any Super Hornets in 2014, but 21 EA-18Gs will keep the line moving. Any foreign military sales would further extend the production line—the likely Australian order for 12 EA-18Gs is the firmest, but the Super Hornet is active in competitions for orders in Brazil, Denmark and the United Arab Emirates. More orders will keep the Navy's options open until the F-35C's IOC date firms up.
A comparison of the F-35C and the Advanced Super Hornet, as proposed byand , shows that the aircraft are similar in many ways. The F-35's advantage is a higher degree of stealth, plus the ability to carry two rather than one 2,000-lb.-class bomb in “stealth mode,” but Boeing contends that its design is survivable, with reduced radar signature and electronic combat systems, while being less costly to acquire than the F-35C.
The F-35C has never been intended to replace the Super Hornet and Growler, and if the F-35C program proceeds as now planned, the F-35C will continue in full-rate production through 2032—which would be the earliest date at which an F/A-18 replacement could be delivered. The Navy is working on service-life extension programs that allow the Super Hornet and Growler to meet operational commitments through 2035. Today, the F/A-18E/F fleet “has flown approximately 30 percent of the available 6,000 total flight hours,” the Navy says, but the current life-extension program can deliver 9,000 hr. “at low risk.”
That lifetime could be extended by a possible major change in carrier operations, as a result of the automatic landing and flight guidance technology demonstrated under the X-47B Unmanned Combat Air System Demonstrator program (see page 42). Using the same basic principles as the Joint Precision Approach and Landing System (Jpals), which is to be fitted to all U.S. Navy carriers, an F/A-18 surrogate aircraft demonstrated the ability to land with 10-12-ft. longitudinal touchdown accuracy and 9-in. lateral accuracy.
Automatic landing is possible on any aircraft that has a sufficiently capable flight control system, with integrated auto-throttle, and in itself is not new to the U.S. Navy. Until now, the limiting factor is that the Navy's current auto-land system uses radar, which betrays the carrier's location and can handle only one aircraft at once. The GPS-based Jpals is silent other than a short-range, narrow-band data link.
Auto-land is important in terms of airframe life, because the number of catapult engagements or “traps,” which impose severe, specific stresses, is a limiting factor on aircraft service life. After the X-47B's first launch from the carrier George Bush in May, senior Navy officers indicated that the service was looking at automatic landing—and higher-fidelity guidance for manual landings—to reduce the number of “field carrier landing practice” missions and actual arrests needed to maintain pilot proficiency.
Consequently, the Super Hornet and Growler out-of-service date has moved beyond 2035. This boosts the case for upgrades such as General Electric's proposed new engine and Boeing's conformal fuel tanks and stealth enhancements (AW&ST May 27, p. 24), both because there is a longer payoff period and the aircraft will be facing more demanding threats. The Growler, in particular, can benefit from conformal fuel tanks and more power, because it routinely operates at high-weight, high-drag conditions with ALQ-99 jamming pods and external tanks.
The Navy has a somewhat different mix of missions from the U.S. Air Force, leading to some differences in philosophy. Chief of Naval Operations Adm. Jonathan Greenert raised eyebrows last summer with a commentary in the U.S. Naval Institute's Proceedings magazine that appeared to cast doubt on the value of stealth. However, its real focus was on the use of payloads—missiles and sensors—to add capability to existing platforms.
That trend is apparent in Navy anti-surface warfare (ASuW) developments, which include sensors and so-called “net-enabled” weapons—missiles that take advantage of other sensors to find and hit targets, but that can still function if communications are down. TheAdvanced Airborne Sensor radar, carried on the new maritime patrol aircraft, is designed to detect, classify and identify sea targets at long range and hand them off to a net-enabled weapon.
The new ASuW weapons include a planned program for an air- or sea-launched weapon to replace Boeing's Harpoon and Standoff Land Attack Missile-Extended Range. Candidates could include Raytheon's Joint Standoff Weapon-Extended Range. A longer-term program is the Navy/Long-Range Anti-Ship Missile based on the Joint Air-to-Surface Standoff Missile but with a seeker combining passive radio-frequency sensing with an imaging infrared terminal sensor. Tests of the sensor started in May 2012 and continued through the early part of this year, with the first of three live firings due this summer.
These are standoff weapons that do not expressly require a stealthy platform, particularly since the “shooter” can approach the target without using radar to detect it, having been cued by the anti-aircraft system or another off-board asset.
|F-35C||Advanced Super Hornet|
|Initial ops capability||2019||2018|
|Acquisition cost, fiscal 2012||$115 million||$88-92 million|
|Configuration||Clean||CFTs / Weapon Pod|
|Active electronic warfare||Forward aspect X-band||All-round, multi-band|
|Weights / Loadings|
|Ops Empty Weight||34,800 lb.||32,650 lb.|
|Internal / conformal fuel||19,750 lb.||18,450 lb.|
|Internal weapon load||4,700 lb.||2,700 lb.|
|Estimated takeoff weight||61,000 lb.||55,000 lb.|
|Thrust, Intermediate / Max||27,000 /43,000 lb.||29,500 /44,000 lb.|
|Thrust, Int / Max (contingency)||NA||35,400 / 52,800 lb.|
|Wing area, gross||680 sq. ft.||500 sq. ft.|
|Wing area, net||376 sq. ft.||400 sq. ft.|
|Ratios / Performance|
|Thrust / weight, Int / Max||0.44 / 0.70||0.54 / 0.80|
|Thrust / weight, Int / Max (contingency)||NA||0.63 / 0.96|
|Wing loading, gross / net||90 / 162 lb. / sq. ft.||110 / 138 lb. / sq. ft.|
|Acceleration, Mach 0.8–1.2||greater than 100 sec.||less than 50 sec.|