Two green discs in the dark and a deep humming noise – to many, these are the calling cards of the 7th SOS CV-22B Osprey departing or returning from another night sortie. But what do these elusive tilt rotors actually get up to on their nocturnal flights? Ben Montgomery joined the crew of a CV-22B from the 7th Special Operations Squadron, 352nd Special Operations Wing over at RAF Mildenhall to find out more.
For those who know of the Osprey, the first aircraft that probably comes to mind is the MV-22B of the United States Marine Corps. Although sharing the same basic airframe with its more numerous relative, the US Air Force’s CV-22B Osprey is an entirely different asset altogether. Counter to what you might expect, the “C” in CV-22 does not indicate a Cargo variant of the aircraft, but as the USMC had already claimed the MV-22 – which would be the normal designation for a special/multi-mission aircraft, the US Air Force went for the CV-22. This article will not delve into the history of the V-22 and its somewhat troubled path to operational readiness, but that is available to read in a 2014 AeroResource article charting the 25th Anniversary of the Osprey.
The Osprey Mission
Within the Special Operations community, there is an emphasis on what can be achieved in a night – or in “one period of darkness”. This is where the Osprey excels; extending the range far beyond what was possible with the MH-53J Pave Low – the aircraft it has directly replaced. The USAF defines the role of the CV-22B as being able to “conduct long-range infiltration, exfiltration and resupply missions for special operations forces”. In other words, the Osprey needs to be able to fly for long distances carrying special operations troops, equipment (and sometimes vehicles) and then deliver them safely to their objective with minimal interference or detection from hostile forces.
The CV-22B Osprey by dint of its mission spends most of its time at either low altitudes, on night operations, or both. To adequately penetrate the advanced air defences it may come up against, typical sortie altitudes can be down to as low as 100ft. In these situations the Osprey operates blacked out, with the crew using night vision equipment. External lights will be off; although a set of visible green (or Infra-Red) lights on the rotor tips can help identify the aircraft to allies or other aircraft in the formation. A forward looking infra-red camera (the AN/AAQ-27 MWIR) is mounted under the nose to help the aircrew see through not only darkness, but also smoke, haze and adverse weather conditions.
To help with navigation at night, the APQ-186 TF/TA Multi Mode Radar on the aircraft is capable of operating over the full envelope of speed and altitude of aircraft. Digital navigation systems and software provide the capability to interface radar data with maps on the cockpit MFDs, providing a map overlay of digitised terrain elevation data. This can help ease crew workload, as the pilots can fly “by the band” – with anything red on the map being above the desired altitude, and anything yellow around it.
Around three quarters of the flight time for the 7th SOS is in night time conditions, and the unit conduct extensive training under Instrument Meteorological Conditions (IMC) – with a total of approximately 2,500 flying hours (day and night) accrued in the UK to date. Training opportunities in the UK are broadly similar to those found at Hurlburt Field in Florida, and allows all necessary training to be conducted in country (although some more specific environments such as desert locations obviously require travel to reach, just as they do when flying from Florida).
Although optimised for low level, the Osprey is still perfectly capable of performing at high altitude. As the aircraft is unpressurised, oxygen systems need to be provided for the aircrew and any passengers. An On-Board Oxygen Generating System (OBOGS) provides breathable oxygen for the flight crew over the complete mission duration, and for any personnel in the rear of the aircraft, a Liquid Oxygen System (LOX) can be fitted. Up at high altitudes the Osprey is able to conduct High Altitude, Low Opening (HALO) airdrops, and equipment drops if required – or simply transit more efficiently between destinations.
Flying the CV-22B – 7th SOS Joint Warrior Sortie
It was for a high altitude mission that the CV-22B was employed during the sortie AeroResource flew on. As part of Exercise Joint Warrior 2015-1, the 7th SOS were required to support Military Free Fall (MFF) drops for troops of 16 Air Assault Brigade. The mission was for the crew of four (Pilot, Co-Pilot, Flight Engineer and Tail Scanner) to depart RAF Mildenhall and fly down to RAF Brize Norton. At Brize, and following a brief with jump instructors from 16 Air Assault Brigade, we would pick up the parachutists before transiting down to Salisbury Plain Training Area to conduct a parachute drop. The drop was scheduled to take place around 30 minutes after sunset, and even with a clear forecast (unlimited visibility and scattered clouds at 3,000ft for the drop zone) it would be pretty gloomy by the time the jump occurred.
The mission brief took place several hours before the flight – an indication of the amount of work required to fly – and many hours of paperwork would have preceded that. Whilst the Pilot and Copilot continued with the paperwork and planning, the two Flight Engineers headed out to the aircraft to start the pre-flight checks needed to get the aircraft ready to fly. Our CV-22B, tail 0033 (07-0033) is one of the oldest on the unit, and is a combat veteran of Afghanistan – having previously served with the 20th SOS, 0033 was one of the first four CV-22Bs to visit RAF Mildenhall during a deployment in spring 2011. The 7th SOS is assigned some of the newer aircraft in the fleet (with the exception of 0033, 0046 and 0050, all are Fiscal Year 11 or later), which is a contributing factor towards their higher than normal mission availability rate. Units in the Contiguous United States (CONUS) have older aircraft, including some Low Rate Initial Production (LRIP) models, with the first operational CV-22 being delivered to the 1st Special Operations Wing in 2007. The first combat operations with the CV-22 took place in Iraq in 2009.
Firing up the Auxiliary Power Unit (APU) early on, the aircrew worked with ground crew to take the Osprey through a full set of functional checks, including built in tests of the onboard computer systems, communications systems and a flight control systems check. To accomplish the latter, the Osprey has three sets of hydraulic systems on the aircraft – all pressurised to 5000psi. Systems 1 and 2 operate the flight controls, whilst System 3 provides power to utility systems and allows ground check out prior to flight. 3 Flight Control Computers (FCCs) are linked to the hydraulic systems and collectively known as the Vehicle Management System – a pairing which allows the computers to rapidly flag up any faults in the system to the aircrew, reducing pilot workload during flight.
The cockpit of the Osprey consists of five large multi-function displays, which are configurable to display whatever is required to accomplish the current mission objectives (due to the sensitivity of some of the equipment on the Osprey, photos of the cockpit with systems running are unable to be included in this article). Generally the pilot and co-pilot will fly with a full screen map on the inboard screens and an artificial horizon on the outboard screen –other information such as the feed from the Forward Looking Infra-Red camera can be underlaid if desired. A larger central screen presents navigational data, waypoints and other information needed for the flight. This centre panel is mainly the domain of the Flight Engineer, who sits between the two pilots and manages the aircraft systems. The cockpit is not an overly spacious environment for three and so successfully operating the Osprey is all about good Crew Resource Management (CRM) – the aircrew quickly learn any nuances and preferences of their colleagues to allow them to avoid stepping on each other’s toes.
Slightly ahead of schedule, 0033 was ready for departure shortly after 1700L. The Osprey dispersal is very close to the end of Runway 11 – although not actually requiring a rolling takeoff (unless at high weight), the CV-22s normally depart from “Alpha Pad”, a reinforced concrete apron near to the Osprey flight line.
For those who think the Osprey is loud from the outside, it’s the same within – although perhaps not as deafening as you would expect. As the rotors spin up to takeoff power the airframe starts to vibrate steadily. The launch is surprisingly sudden, with a noticeable increase in G-force pushing you into the seat as the aircraft climbed away from the field. With the rotors starting to translate the aircraft accelerates rapidly into the climb to 10,000 feet, heading for the Daventry Corridor.
Up at 10,000 feet on a simple transit there is not much for the Tail Scanner to do – although it’s a different story in the cockpit. The air traffic system in the UK is complex, and on exiting the Daventry Corridor and making the turn for Brize Norton the crew have to deal with multiple control requirements simultaneously. It is situations like this in which the Flight Engineer can assist, handling some radio communications and allowing the pilots to concentrate on flying.
After a short time slotting into the pattern for Runway 26 (behind two locally assigned C-130s), our CV-22B touched down at Brize Norton and taxied in to park. One of the intelligent abilities of the Osprey – a benefit of its advanced flight control computers – is being able to fly a self contained program approach. The crew can select a desired glide slope and approach speed and the aircraft will fly itself to a coupled approach point about 30 feet off the ground, even being able to conduct a turning approach or an approach in terrain following mode. At this point the crew could either take control or give the aircraft permission to continue and land itself.
After landing at Brize Norton, the Pilot and Tail Scanner worked a joint brief with the crew of “Omen 1”, an RAF C-130 also dropping over the Salisbury Plain Training Area. The parachutists in the Osprey would be dropping from 10,000ft whilst “Omen 1” would drop afterwards from 18,000ft, meaning there should be no confliction between the two aircraft. Two instructors from 16 Air Assault Brigade also briefed with the crew over the differences between the procedures of the USAF and British jump methods to prevent from confusion in the air. Joint training opportunities like this provide huge benefit, and increase the capabilities of both parties – potentially critical in an operational scenario. For example here, the Osprey was able to reach drop altitude far faster than a C-130 could – and unlike the C-130 if there was a problem with the drop the CV-22B could act in a Combat Search and Rescue (CSAR) role, rapidly landing and evacuating a casualty to the nearest medical centre. The CSAR capability of the Osprey has not gone unrecognised by the UK Ministry of Defence, with the 7th SOS having recently conducted training within the UK Search and Rescue framework – and the unit stand ready to assist any SAR efforts if requested.
With the sun setting, the jumpers and instructors loaded up on the Osprey. To make moving around onboard the aircraft simpler (which although it could potentially carry a full load of up to 36 passengers or purpose-built 4 person vehicles, felt cramped with less than half that number in the back, mainly because of the significant quantity of equipment that 16AAB use), the parachutists waited until getting airborne to complete kitting up. En route to the drop zone at relatively low level, the ramp was kept raised because of the speed limit of the parachutes the jumpers were using – it is safer if they accidentally deployed with the ramp closed rather than open above their speed limit. The Osprey features a communications console in the rear that allows the commander of the ground troops (16 Air Assault Brigade in this case) to speak directly to the aircrew, providing them with good indications on the mission progress. Once checked in with Salisbury Plain control and cleared onto Danger Area 123, the CV-22 rapidly climbed up to 10,000ft in preparation for the drop.
On the run in to the drop zone, the lighting in the back of the aircraft was extinguished and replaced by low intensity green lighting to help protect the jumpers night vision – they would be exiting the aircraft without Night Vision Goggles (NVGs). The brightest light sources were from the green cylume glowsticks on the back of every helmet, and the red lights strapped to their chests, making for quite a surreal set of colours in the back of the aircraft compared to the dull grey twilight outside.
Given the amount of preparation inside the aircraft the jump itself was extremely rapid – the size of the drop zone being used meant that the full stick of jumpers had only a few seconds to leave the aircraft and still be calculated to land in the drop zone. Watched over by the instructors, the jumpers – now restricted by both heavy bergens attached to their legs and weapons slung over their shoulders, shuffled in single file out onto the ramp and vanished. The twilight made it extremely difficult to spot them on the descent, and it wasn’t until the crew received a call from the ground coordinator to confirm that all jumpers had landed successfully that they were happy to depart the area. The Time On Target (TOT) was only marginally off the estimated time – not bad considering a dummy run was also undertaken, as one of the aircrew was under instruction for qualification to conduct Military Free Fall drops.
Dropping back down from jump altitude and switching to night vision, it was only a short transit back to Brize Norton to drop off the jump instructors (who although they were equipped with sports parachutes did not jump – but could have departed the aircraft in flight in the event of an emergency). Unlike the first stop, during which the aircraft was powered down to APU only, this was conducted rotors running – and the time on the ground was not longer than five minutes.
The flight back to Mildenhall was a simple reverse of the route from the first half of the sortie, although by this point it was entirely dark outside and night vision goggles were the only way to see. Clipping into a ball bearing mount on the front of the helmet and powered by a pair of AA batteries on the back, the NVG set provides around a 40 degree field of view – but destroys depth of field in exactly the same way as a camera.
By the time the aircraft settled back down on Alpha Pad it was long since dark, and the crew were kind enough to conduct an impromptu night shoot – keeping the rotors running and the green tip lights illuminated long enough to capture that characteristic green disc. Standing outside of the aircraft with the rotors spooled down, it is easy to feel the force of the jet efflux from the engine’s core – ducted outwards by a novel Coanda Effect application to keep the hot air away from the temperature sensitive systems onboard the aircraft.
Having shut down the aircraft and handed it back over to the ground crew to complete the post flight checks and maintenance, there was still significant work for the aircrew to complete. After handing back in flight kits (helmets, gunner lines, Night Vision Goggles), a comprehensive post flight briefing ensured any lessons learned were captured (for example – it was suggested that the parachutists should in future be advised to wear more significant ear protection when flying the Osprey), and to run through any issues that the crew encountered during flight. Happily the co-pilot had completed the necessary work to qualify him for to undertake unsupervised MFF operations, providing an additional training aspect to this Joint Warrior mission.
Departing for home after the sortie at some time after 2300L, it is easy to forget the effort behind the scenes to make even one flight on one day possible. From the fence line outside the base, all many see is the aircraft depart and arrive, but not normally actually conduct their mission.
At this juncture we would normally give our gratitude to all of those involved in making this article possible – but in line with AFSOC policy of not naming their personnel, we will simply say, to the 7th SOS crew and the Public Affairs team of the 352nd SOW, thank you!