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	Director, Operational Test & Evaluation
	FY98 Annual Report

SYSTEM DESCRIPTION & CONTRIBUTION TO JOINT VISION 2010

The MH-47E Special Operations Aircraft (SOA) is a derivative of the Boeing CH-47 Chinook. Along with other modifications, it has a significantly increased fuel (800-gallon) capacity with modified main and auxiliary fuel tanks. The MH-60K is a derivative of the Sikorsky UH-60 Blackhawk. Its modifications include a significantly increased fuel capacity with two 185-gallon internal fuel tanks, side-by-side, against the rear bulkhead. Both aircraft have modified integrated avionics suites and multi-mode radar, and are intended to provide adverse-weather infiltration/exfiltration and support to U.S. military forces, country teams, other agencies, and special activities. These U.S. Special Operations Command (USSOCOM) aircraft contribute to the Joint Vision 2010 concept of dominant maneuver by helping to create asymmetric advantages for combined application of land, air, and sea power against enemy defenses within the joint environment. They are eminently capable, as modernized, multi-mission platforms operating within tailor-to-task organizations, of supporting precise, agile, fast-moving joint operations.

Due to their funding thresholds, the MH-47E and MH-60K SOA programs were not required to undergo operational test oversight from this office. However, these systems do qualify for LFT&E oversight.

These aircraft were treated as one program, which was placed on the LFT&E oversight list in October 1991. Since the program was past Milestone III, the National Defense Authorization Act for Fiscal Year 1993 made provisions to complete LFT&E prior to the Full Materiel Release Decision. The Acquisition Executive for USSOCOM has granted this system a waiver from full-up, system-level live fire testing. Letters notifying Congress of this waiver, along with the accompanying LFT&E Alternative Plans were submitted by the USSOCOM Acquisition Executive to the USD (A&T) on December 22, 1997. The required Alternative LFT&E Plan which included both aircraft was approved by DOT&E in July 1997. The DOT&E LFT&E Report on the results of this testing will be forwarded to the defense committees of the Congress in FY99.

Under the approved plan, testing was limited to the major changes to the aircraft. In the case of the MH-47E, change occurred via the addition of an 800-gallon Robertson Auxiliary Fuel Tank in the cabin and Boeing designed sponson tanks with expanded capacity and honeycomb shell construction. For the MH-60K, it was the addition of two 185 gallon Robertson Auxiliary Fuel Tanks in the cabin.

Analyses conducted during the test planning phase revealed two potential vulnerabilities. The first potential vulnerability was associated with projectiles entering the fuel tanks in the volume above the liquid fuel. Such impacts could ignite the fuel vapors and cause widespread explosions and/or fires. During test planning, USSOCOM decided to add an inerting system to the fuel tanks to avoid such fires/explosions. The MH-47E will be a lead-the-fleet system that will be available for similar helicopter variants in other fleets as well. A second potential vulnerability was associated with projectiles impacting the fuel tanks below the fluid level and causing loss of fuel and or fires. To address this possibility, a series of tests were completed at Aberdeen Proving Ground in August and September of 1997, using a variety of expected threats. In approving the alternative plan, DOT&E requested that additional tests be conducted with larger caliber threats if the test articles remained viable after the planned series of shots. These tests were completed in March 1998.

The MH-47E fuel tanks and the MH-60K auxiliary fuel tanks demonstrated exceptional ability to withstand ballistic impacts of projectiles associated with small arms, automatic weapons, and anti-aircraft artillery. The tanks are designed to be self-sealing against .50 projectiles. However, the live fire tests indicated that the tanks designs are effective against much larger non-exploding projectiles, even with multiple impacts on the same tank. The designs also proved to be effective in mitigating the fuel loss from impacts by HEI projectiles. In addition, there were no fires in the 23 shots except for one, which self extinguished before any significant damage was done. One of the reasons for the strength of this design against ballistic threats is in part due to the fact that the tanks are designed to be crashworthy and this adds to the robustness against the ballistic threat.

The LFT testing on these systems was completed in May 1998 and the Army's data reports were delivered to OSD in June 1998. The DOT&E independent LFT&E Report is in draft form awaiting the Army's final evaluation report which is expected to be delivered in 2QFY99. The DOT&E independent evaluation report will be delivered to Congress well within the required 45 days from the time that DOT&E receives the Army's evaluation.

The self-sealing fuel tanks of the MH-47E and the MH-60K were found to perform better than expected. The Army is examining the potential use of these designs on other aircraft such as the CH-47D upgrade.

One of the "lessons learned" from this LFT&E program is that the initial analysis of an aircraft conducted to identify Live Fire Test issues can have a direct impact on the design of the aircraft and should be done carefully. In the case of the Special Operations Aircraft, fuel tank ullage explosion was identified as a potential vulnerability based on analysis and past testing. The analysis was sufficient to cause Special Operations Command to pursue fuel tank inerting without the cost of additional testing.

The fuel tank inerting is also an example where a design feature incorporated to reduce ballistic vulnerability can have a positive effect on system safety. Inerting the fuel tanks will reduce the hazards of fire and explosion from non-threat events such as in the TWA 800 accident.

Another "lesson learned" is that the Live Fire Test plans should be prepared with foresight to anticipate unlikely results, either negative or positive. In this particular case, it appeared unlikely that the test articles would be viable after testing with what was believed to be the maximum survivable threat. At the request of OSD, the Army included a contingency plan to increase the test threats if the test article survived. The articles survived the initial threats, the Army tested them with larger threats and DOD now has the benefit of increased knowledge.