Boeing will offer its HH-47 for the USAF’s revised aircrew rescue requirement. But can the veteran design deliver?
Boeing’s HH-47 Chinook is one of three known candidates for the US Air Force’s next-generation combat search and rescue (CSAR-X) requirement, but the presence of the 1960s-era airframe as a competitor signals a massive shift in the customer’s priorities over the past year.
The CSAR-X acquisition strategy began to take shape in earnest two years ago, and the US Department of Defense’s office of industrial policy last year described the then-labelled Personnel Recovery Vehicle programme as the “most promising near-term opportunity to inject innovation” into the rotorcraft market, mainly in the area of speed. At that time, the USAF announced a strategy to buy a mixed fleet starting with a Block 0 conventional helicopter followed in the programme’s later stages by a Block 10 aircraft with tiltrotor-like speed.
The USAF has an urgent need to retire around 100 ageing and overburdened Sikorsky HH-60G Pave Hawks now performing the CSAR mission – but delivering a mission readiness level of only around 66% – and a conventional helicopter could be delivered faster and for less money. However, the service also remained hopeful that the mixed-fleet proposal would eventually introduce a platform with tiltrotor-like speed.
Plans for a mixed fleet started to unravel late last year, and by January a draft requirements document was released that eliminated the programme’s original strategy and lowered the overall speed requirement to 135kt (250km/h). The latter move made it possible for the Chinook – in a baseline MH-47G configuration – to enter the competition, says Bob Sobey, Boeing’s deputy director for helicopter programmes. The shift also prompted Bell Boeing to announce last month that it would not submit a bid based on the CV-22 Osprey tiltrotor.
Boeing’s proposed HH-47 is joined in the competition by familiar – and conventional – helicopter competitors in the form of Lockheed Martin/AgustaWestland/Bell Helicopter US101, and the HH-92 offered by Sikorsky and systems integration partner Boeing Air Force Systems.
That the Chinook trumped the Osprey in clearing at least the first hurdle of a competition that had once placed a premium on aircraft speed may be incongruous. But Boeing, an equal partner in the V-22 design with Bell, says the USAF’s reasoning was clear. “If you can get to where you have to be faster, but then can’t hover [at high altitude or in hot weather conditions] to pick them up, you haven’t done anything,” says Sobey. He also dismisses the DoD’s stated hopes for the CSAR-X programme to spark innovation in the rotorcraft market, noting that tiltrotor technology was invented in the 1950s and that there has been no real breakthrough in conventional helicopter speed since about the same time.
It is also clear that the USAF now regards the speed issue as more than a function of distance to the target. Speed in CSAR missions is also a function of how precisely the aircrew knows the location of the survivor. The most difficult problem with the CSAR mission tends to be in exactly locating the downed crew members in the terminal phase of the mission. Existing locator systems and on-board communications equipment for the HH-60 are inadequate and the air force has moved to increase the overall level of situational awareness in the CSAR-X platform’s cockpit in an attempt to reduce or eliminate the amount of time needed to locate survivors in the last stage of a rescue mission.
The significance of the Chinook’s presence in the US Army inventory remains an unknown factor in the CSAR-X competition, but the latter service is openly pushing for the design to win. Success in the air force contest could fund several improvements to the Chinook airframe that could be transferred to army MH-47G and CH-47F airframes, says Col William Crosby, the service’s utility helicopter programme manager. The CSAR-X Chinook, for example, would require a new electrical system, a more advanced electronic warfare suite and a redesigned rotor blade. Boeing also hopes to make changes to the Chinook’s airframe to reduce drag and increase aircraft speed.
The USAF also may be in a position to benefit from tapping into the army’s existing production line for the Chinook. Boeing is now preparing a bid that will include an option to allow the air force to buy its entire 141-aircraft CSAR-X fleet several years earlier than currently planned, says Sobey. The USAF’s current planning calls for the new aircraft to achieve initial operating capability early in fiscal year 2012.
But the Chinook’s late entry into the bidding cycle has left the team facing some difficult challenges. Boeing first has to demonstrate that it can reassemble an HH-47 within 3h after being airlifted aboard a Boeing C-17 or Lockheed C-5 transport. The current US record for reassembling a CH-47 in the “advanced transportability” configuration is 3h 15min, but Boeing hopes to demonstrate compliance with the requirement during a demonstration scheduled for the first week of December.
Another challenge will be in providing a representative airframe to participate in a “basic aircraft flight evaluation” to be conducted at Nellis AFB in Nevada by early December. This should not be viewed as a “fly-off”, says an industry source involved in the programme, but rather as “an opportunity for the air force to assess risk” associated with each of the bidding airframes. Boeing last week signed a lease agreement with the US Special Operations Command to bail back two MH-47Gs to be used during the demonstration.
The process will take about a week and demonstrate the rival systems’ hover-and-hoist and maintenance-tracking capabilities, and assess their multi-mission cabin configurations. The bidding companies have until 21 November to respond to a USAF request for proposals. A contract award is expected in May 2006
STEPHEN TRIMBLE/WASHINGTON DC
Source: Flight International
