The US Air Force has announced that it wants to start replacing 62 Vietnam-era UH-1Ns with up to 93 new helicopters after 2015.

A "sources sought" notice issued on 17 December for the potentially multi-billion dollar common vertical lift support programme (CVLSP) reveals both the quantity and the USAF's desired attributes for the new helicopter fleet.

The USAF wants to replace its UH-1Ns with a helicopter that can lift 1,449kg (3,194lb), including four crew members, nine passengers and mission equipment, the notice says. It should also be able to fly up to 3h without refuelling at speeds up to 135ktas (251km/h).

Survivability is a key area that USAF wants to upgrade with the new helicopter. Industry sources were asked to describe how their aircraft could survive if struck by bullets as large as the 7.62mm, which is fired by the AK-47.

 UH-1N 445
 Photo by US Air Force
The CVLSP helicopter also should be armed, with the ability to suppress an "eight-man enemy element in the open out to 800m during daylight with 3sec of detection time", the notice says.

The USAF also makes it clear that the CVLSP contract is expected to be awarded to an off-the-shelf helicopter, meaning it must already be in service with either government or private owners.

The US military has had a chequered history with helicopter development programmes over the past decade.

The US Army has successfully fielded the unarmed EADS North America UH-72A Lakota as a light utility helicopter. But cost overruns and schedule delays forced the military to abort three programmes. Since 2004, the army terminated contracts for the RAH-66 Comanche and ARH-70 Arapaho. The US Navy also terminated a contract to redesign the EH101 as a presidential helicopter called the VH-71.

Meanwhile, the USAF was forced to cancel plans to buy a combat search and rescue (CSAR) helicopter after the original award was overturned and two follow-up attempts were declared invalid.

The CSAR and CVLSP programmes were originally part of the same contract, but the USAF separated them in 2005.

According to USAF budget justification documents released in February 2008, the CVLSP fleet is envisioned to provide escort for nuclear convoys, respond in any weather to emergencies across the far-flung launch silos for intercontinental ballistic missiles and transport passengers in the Washington DC area. The aircraft also could support NASA and homeland security missions.

The requirements in the acquisition notice call for an aircraft that is only marginally larger than the UH-1N. For example, the unarmed UH-72 could satisfy the lift, speed and endurance requirements, but lacks armoured protection and weapon systems. EADS has teamed up with Lockheed Martin to demonstrate an armed variant called the AS635. Both the UH-72 and AS635 are derived from the Eurocopter EC145 helicopter.

Other helicopters in the same class include the AgustaWestland AW129 multi-role combat helicopter and the Bell Helicopter 412EP.

Source: Flight International