Tommy Dunehew, Vice President, Business Development Global Mobility Systems Boeing C-17 ‘Globemaster III’ spoke to SP’s about the unique attributes of C-17. Read through the interview to know in detail about the C-17

SP Guide Publications (SP’s): What are the technical features and operational attributes that make the C-17 Globemaster III unique among other similar military transport aircraft in the world?

Dunehaw: Reliability and maintainability are two outstanding benefits of the C-17 aircraft. Current operational requirements impose demanding reliability and maintainability standards. These include an aircraft mission completion success probability rate of 92 per cent, only 20 aircraft maintenance manhours per flying hour, and full and partial mission availability rates of 74.7 per cent and 82.5 per cent, respectively. The Boeing warranty assures these figures will be met.

The C-17 measures 174 ft long (53 m) with a wingspan of 169 ft, 10 in (51.75 m). The aircraft is powered by four, fully reversible, Federal Aviation Administration-certified F117-PW-100 engines (the military designation for the commercial Pratt & Whitney PW2040) currently used on the Boeing 757. Each engine is rated at 40,440 lbs of thrust. The thrust reversers direct the flow of air upward and forward to avoid ingestion of dust and debris. Maximum use has been made of off-the-shelf and commercial equipment, including Air Force-standardised avionics.

The aircraft is operated by a crew of three (pilot, co-pilot and loadmaster), reducing manpower requirements, risk exposure, and long-term operating costs. The cargo is loaded onto the C-17 through a large aft door that accommodates military vehicles and palletised cargo. The C-17 can carry virtually all of the DoD’s air-transportable equipment.

Maximum payload capacity of the C-17 is 164,900 lbs (77,519 kg), and its maximum gross takeoff weight is 585,000 lbs (265,352 kg). With a payload of 169,000 lbs (76,657 kg) and an initial cruise altitude of 28,000 ft (8,534 m), the C-17 has an unrefueled range of approximately 2,400 nautical miles. Its cruise speed is approximately 450 knots (.76 Mach). The C-17 is designed to airdrop 102 paratroopers and equipment.

The design of the aircraft allows it to operate through small, austere airfields. The C-17 can take off and land on runways as short as 3,500 ft (1,064 m) and only 90 ft wide (27.4 m). Even on such narrow runways, the C-17 can turn around using a three-point star turn and has backing capability.

SP’s: How would the aircraft perform in ‘high & hot’ conditions found at Leh, Thoise, etc? Under special circumstances can the aircraft operate from Daulat Beg Auldi (DBO) at approximately 16,500 ft amsl and with how much maximum payload?

Dunehaw: The aircraft routinely operates in high and hot environment. Regular missions are performed in airfields as high as 13,000 ft. The environmental conditions (temperature and winds) and the operational requirements (reserve fuel and fuel for return mission) ultimately dictate how much payload can be airlifted to and from airfields such as Leh. Under summer conditions, the aircraft could lift approximately 40 tonnes (88,185 lbs). It is highly unlikely that significant payloads could be delivered at extremely high altitude airfields. In those conditions, airdrops would be far more efficient.

SP’s: What is the percentage of composites employed in the construction of the C-17 airframe?

Dunehaw: The horizontal tail is the only major component that is all-composite construction. Newer aircraft have this feature as a weight-savings measure; the composite tail weighs approximately 500 pounds less than the former aluminum alloy tail.

SP’s: What are the navigation systems available on the aircraft, both autonomous and ground-based aids, to achieve high degree of accuracy in global navigation?

Dunehaw: The C-17 comes fully equipped with a GPS navigation system as well as systems to receive all ground-based navigation signals (ILS, VOR, DME, TACAN and beacons.

SP’s: Could you throw light on the C-17 load-carrying capabilities under different parameters such as range, runway condition/length etc?

Dunehaw: This chart provides relevant information to your question.

SP’s: What makes the aircraft capable of operating from unlit and unpaved runways under night conditions? What are the safety margins while operating under such conditions and whether it can be done routinely?

Dunehaw: The C-17 operates routinely into austere (unlit and unpaved) runways any time of the day. The aircraft is fully configured for night vision goggle (NVG) operations (cockpit, cargo compartment, exterior lighting) that enablethese manoeuvres to be conducted safely during night time conditions. Air crew training includes extensive lessons in the use of NVG equipment on board the aircraft.

SP’s: One of the major attributes of the C-17 is its quick loading/off-loading and turn around capability. Does it call for major ground-handling facilities?

Dunehaw: The C-17 cargo compartment was designed to be capable of fully self-contained loading/off-loading. The aircraft ramp is adjustable to any height from the ground to truck-bed height, enabling it to handle roll-on, roll-off, palletised, and airdrop loads. The rail and roller systems can be reconfigured in minutes by a single loadmaster, even during flight. Palletised cargo can also be combat offloaded directly onto the ground where no material handling equipment is available. Coupled with its ability to back up under its own power, the C-17 is the most versatile airlifter in terms of quick turnaround, on- and off-load capabilities.

SP’s: Can reverse thrust on the engines of the C-17 be applied when the aircraft is in flight? If so, what are the implications of one or more engines failing to unreverse and how would the crew handle such an emergency?

Dunehaw: Yes, the C-17 is capable of reversing the thrust in flight and uses this feature to accomplish quick descents into hostile operating areas. The thrust reverse system on the aircraft is extremely reliable. Even when it fails, the affected engine could be shut down leaving the aircraft still capable of safe flight and landing.

SP’s: What is the concept of performance-based logistic support that the OEM offers with the C-17 to the USAF? Would such an offer be available for India too along with the fleet of 10 aircraft that are proposed to be acquired for the IAF?

Dunehaw: The Indian Air Force (IAF) can participate in Boeing’s Globemaster III Sustainment Partnership (GSP). GSP is a public/private agreement designed around the concept of performance-based logistics where the customer pays for readiness, not specific parts or services. Under the agreement, Boeing is responsible for all C-17 sustainment activities, including material management and depot maintenance support. The partnership capitalises on Boeing’s expertise, with air force depots, to ensure readiness levels which meet the warfighter’s needs.

The GSP programme has become a model for the future of sustainment. Boeing has supply support management for more than 95 per cent of the reparable parts on the C-17. The company continually exceeds the contract requirement of 82 per cent parts issue effectiveness (delivery rate). For the period of FY 2004 to FY 2009, GSP supply chain management achieved an average of 90 per cent delivery rate for these assigned reparable items. Boeing is responsible for supply support, supplier management, technical manual support, maintenance, modifications and upgradation, logistics engineering services and field support services. Boeing personnel come into contact with the aircraft everyday in the field, working alongside air force personnel to keep the C-17 fleet flying with the best availability in airlift history.