Goodbye gravel truck

The RAAF Caribou story began in early 1962 when the Menzies government ordered 18 aircraft as part of a general re-equipment program for the RAAF that included purchases of F-111s, extra Mirage IIIs, Macchi MB-326s, Iroquois, HS.748s, P-3B Orions and C-130E Hercules. A further 11 Caribou would be ordered in succeeding years to bring the final total of RAAF Caribous to 29.

The Caribou was bought to replace the WW2 era Dakota. While it may have seemed counter-intuitive to replace the DC-3 with an aircraft that had less range and was slower, the Caribou’s sublime short field performance and its rear loading ramp promised to add capabilities for the RAAF that would amply make up for any minor outright performance limitations, while nicely complementing the larger C-130 Hercules.

Looking back it is surprising that the Caribou’s entry into RAAF service was inauspicious, with the first aircraft, A4-134, being written off after a demonstration STOL landing at Nowra went terribly awry just 10 weeks after the aircraft had been delivered. A combination of a downdraught on finals and inexperience on type was blamed; however it served as a warning that the aircraft demanded respectful handling in the low speed regime it frequently operated in.

Wallaby Airlines

The third ferry flight of three Caribou arrived in Butterworth in Malaysia in August 1964 and were promptly re-routed to Vietnam where they formed the basis of the RAAF Transport Flight Vietnam, or RTFV. The Caribous were the first Australian aircraft to arrive in Vietnam and they were the last to leave in 1972. Based in Vung Tau, where there were already US Army Caribou in operation, the RTFV began the first of many missions for the US Air Force’s 2nd Air Division, 315 Tactical Airlift Wing.

The three aircraft of the fourth ferry flight soon joined them and the nickname ‘Wallaby Airlines’ was rapidly coined. Pilots and loadmasters were posted in for a 12 month tour of duty and they could expect to find themselves operating most days of the week into hundreds of basic unprepared airstrips throughout the country. The hours they flew were enormous. Flying 10 sorties per day or more, aircrew could routinely clock up over 1250 hours during their tour.

The loads would vary from troop insertions, ammunition and cargo drops to milk runs between major bases. Quite often the crews were expected to carry livestock for the local populace. The aircraft were also fitted with armour plated seats to cope with continual small arms fire. All of the 12 Caribou that eventually operated in Vietnam sustained damage of some sort from enemy action.

Wallaby Airlines began to garner a reputation for efficiency that put their US counterparts in the shade. The statistics showed that the RTFV and later 35 Squadron flew only 1.4 per cent of the total transport sorties of the war, yet carried over seven per cent of the total freight.

”We had six Caribous … the Yanks thought we had 26,” John Staal, a Vietnam era RAAF Caribou pilot, reflected.

In June 1966 the seven aircraft now being operated by the RTFV were folded into 35 Squadron (which had been stood up after a 20 year hiatus), which began to operate with the US Air Force’s 834th Air Division of the 7th Air Force. 35SQN would continue to operate in Vietnam until its return to Australia in February 1972. It was awarded the Gloucester Cup in 1967 as the most proficient RAAF squadron of the year, and General Westmoreland (commander of all US military forces in Vietnam from 1964-68) was so impressed by their efficiency that he made a formal request to the Australian government for 12 more Caribou. However, this request was denied due to operational requirements back in Australia.

Three Caribous were lost in Vietnam. A4-185 ran off the side of a runway after a parachute load failed to extract and the crew decided to land on the extremely narrow A Ro airstrip in order to deliver their cargo. The aircraft was written off but the nose section soldiered on as a makeshift observation post.

A4-171 suffered the indignity of a ditching when the crew lost external reference whilst approaching the An Thoi airstrip during a heavy rain squall. Of the 16 people on board only the loadmaster suffered slight injuries.

The only RAAF Caribou lost to enemy action was hit on the ground by mortar shells at That Son while delivering fuel drums. PLTOFFs Bert Milne and Mick Calvert and CPL Nev Church were forced to run for cover when a mortar shell tore through the starboard wing of A4-193 on the March 29 1970.

There were other accidents of varying severity. A4-152 needed to be shipped back to Australia for repairs after another landing accident on a rough airstrip. A4-173 also needed in-field repairs after a short landing resulted in striking the runway lip at a Special Forces base. A4-210 was inadvertently taxied into a ditch, the damage eventually causing the aircraft to be returned to de Havilland in Australia for re-rigging.

Considering the tempo of the Vietnam operations, the rough qualities of the average strip they operated into, the constant small arms fire and the environmental difficulties they encountered in the tropics, the wonder is that there were not more losses. Remarkably, there were no fatalities on Wallaby Airlines’s watch for the entire Vietnam conflict.

As far as operational efficiency was concerned the statistics from Vietnam speak for themselves. In seven years almost 80,000 sorties totalling 47,000 hours were flown, with 677,000 passengers carried and 41 million kilograms of freight delivered. The legend was off and running.

PNG Operations

Back home, 38SQN had continued to operate its Caribou from RAAF Richmond, and from 1965 until PNG Independence in 1975 also operated a detachment of two aircraft based in Port Moresby. This detachment marked the beginning of a long association with PNG for the Caribou that continued until retirement. With its low pressure tyres, supercharged radial engines and double-slotted full span Fowler flaps, the Caribou was able to carry worthwhile loads into mountain strips that were previously the domain of light aircraft.

Flying in PNG is demanding – “Always give yourself an out…” was the Caribou QFI’s PNG mantra. The Caribou was unpressurised and although it carried supplemental oxygen crews generally had to rely on their map reading skills to pinpoint the various “gaps” that would allow access to valleys without flying above the clouds. Correct identification of these gaps was vital and techniques were developed to ensure pilots always had Plan B ready to go should the weather close in or if a gap was misidentified before entering. Crews were taught to approach a gap from the side at a speed which allowed rapid deployment of flap. In this way a surprisingly tight turn could be initiated back down a valley if required should the gap be blocked by cloud.

This type of flying tended to hone the pilots’ situational awareness and navigational skills. It had to because the cost of a mistake was high and GPS was not retrofitted until the 1990s. Many of the airstrips flown into were one-way in that a landing could only be made in one direction and the take-off in the other. Each airstrip had its own idiosyncrasies which had to be taken into account. For instance, Tapini, northwest of Port Moresby, is a mountain strip which has its own ‘ILS’, a goat track on the mountain face opposite the strip which pilots flew down and approximated the correct approach slope required to land. It even had the equivalent of an outer marker which was a small waterfall that identified it as the correct goat track to use out of several on the mountain. The base leg of the approach was flown hugging the ‘ILS’, followed by a tight left turn. After landing the runway was so steep it required pilots to add power to reach to the top of the strip. This was not an unusual feature of many of the strips the Caribou operated into.

PNG took its toll on the Caribou fleet over the years with several accidents. The worst of these was the crash of A4-233 which occurred in the Kudjeru gap on August 28 1972. This accident, possibly caused by an aborted attempt at crossing through the gap and striking rising terrain on the egress, was the only fatal Caribou accident in 45 years of RAAF operations. Twenty-seven people, including all of the crew, were killed and just four survived. This accident was also unique as it was the only one to occur outside the landing or takeoff phase of flight.

Other Caribou losses in PNG were generally caused by misjudging the approach slope or attempting to go around into terrain that would not permit it. This occurred on June 3 1965 when a crew misidentified an airstrip and attempted to go-around at Pogera in the Highlands. The subsequent collision with the ground wrote off A4-202.

Tapini itself accounted for A4-147 on October 6 1968 when it landed short of the runway lip. Flying into a mountain strip can cause optical illusions affecting the ability to fly a correct approach slope, and that may have been a factor in this accident.

The last major accident in PNG happened in 1978 when a 35SQN aircraft crashed on takeoff at Telefomin due to a loss of directional control caused by wet grass and runway slope. The aircraft, A4-164, was lifted out beneath a Chinook and returned to Australia for repair and eventual return to service.

Because of the inherent risks of PNG operations the two Caribou squadrons created the position of ‘PNG Captain’, which signified that the holder had the required experience and skill to safely operate a Caribou in country. PNG captains were generally B Category or very experienced C Category captains and the appellation was highly sought after.

“The most memorable experiences for me have been the flying I have conducted in PNG and New Zealand. Both countries are absolutely stunning,” said current 38SQN PNG Captain FLTLT Alice Torr.

38SQN pilots put their PNG experience to further good use from 1975 to 1978 when an aircraft was seconded to Pakistan to fly as part of the UNMOGIP (United Nations Military Observer Group in India and Pakistan) group which created to monitor the cease-fire conditions between those two countries, based in the Kashmir region. Three aircraft were painted in the all-white UN scheme for the three years the deployment ran. The Caribou was perfect for the job as it requires operations into unprepared airstrips at altitudes of anything up to 8000ft.

1975 also saw history made with the first ever hijacking of a RAAF aircraft. A4-140 had been hurriedly repainted in Red Cross markings and was operating medical aid shuttles from Darwin to East Timor. On a flight from Baucau the crew was baled up by an armed soldier demanding that they take him and 47 of his closest friends to Darwin. Not arguing, even to point out that Darwin was the destination anyway; they proceeded to get the grossly overloaded aircraft into the air. Anecdotal evidence suggests it took the crew an hour at METO (Maximum Except Take-Off) power to get the aircraft out of ground effect!

“I think the soldier was actually just plain frightened. The crew even managed to get the rifle off him before takeoff…. The biggest problem was getting clearance to land back in Darwin as the “welcoming committee” was taking some time to get their act together; they’d never had a hijack before but the Caribou was flying in on the fumes,” recalled WOFF Graeme Black, an 8500hr Caribou flight engineer veteran.

The early 1980s marked a general withdrawal from international duties but the two squadrons were fully occupied in the myriad roles assigned to them back at home. National support missions such as flood relief were flown in 1983 when the drought broke all over NSW and Southern Queensland. It is quite amazing how many hay bales can be dropped in one pass by a motivated crew, ably assisted by the local populace. Once again the Caribou proved ideal by providing a stable platform to deliver the fodder accurately, at a speed which did not shred the bales.

1984 saw A4-231 make its big screen movie debut in the Werner Herzog film, Where the Green Ants Dream. Herzog, a Cannes Film Festival Best Director winner, had apparently been intrigued by the shape and colour of the aircraft, and wrote an entire script around it based in the outback.

In 1986 A4-264 suffered at landing accident at Camden NSW and was written off. This was the last Caribou to be lost in an accident by the RAAF (although A4-199 made an emergency landing at an airfield in the High Range Field Training Area on September 25 this year and was deemed uneconomical to repair, with the type’s retirement so close).

The 20 year anniversary of operations came and went in the mid 1980s and thoughts were already being given to replacing the aircraft. No-one knew then just how difficult that would be. There was no obvious contender, especially since production of the DHC-5 Buffalo (essentially an improved, turboprop powered Caribou) shut down in 1978.

In the mean-time it was already becoming difficult to source critical spares such as propellers, propeller seals and engines, something that would be increasingly a problem over the remaining life of the aircraft. “Obviously a major part of keeping the aircraft flying is spare parts. It is often difficult to convince people that we still need certain parts!” said 38SQN XO, SQNLDR Victoria Rookyard.

This lack of spares was a consideration in 1991 when the Minister of Defence announced a reduction in fleet numbers from 21 to 14 aircraft. The stored aircraft were used to provide an in-house spares base. Then in 1992 38SQN relocated to RAAF Base Amberley, ending a 44 year association with Richmond (35SQN had moved from Richmond to Townsville in 1976).

The Caribou’s unique capabilities were again called upon with the Australian led InterFET mission in East Timor. Elements of 38 Squadron, including four aircraft, deployed to East Timor in October 1999 as 86 Wing Detachment C. Two Caribou remained in country after the InterFET mission was replaced by the UN Transitional Administration East Timor (UNTAET), eventually returning to Australia in 2001.

Caribou replacement? Another Caribou… RAAF maxim

By the time of the Timor deployment serious efforts to replace the Caribou were well underway with Project Air 5190.

“Project Air 5190 was to provide a suitable replacement for the ageing Caribou aircraft. The Request For Tender was issued in May 1998,” recalled project head GPCAPT Geoff Tasker. “IPTN of Indonesia, CASA of Spain and US-Italian Lockheed Martin Alenia Tactical Transport Systems responded to the RFT. IPTN withdrew shortly afterwards. CASA and LMATTS tendered to supply CN-235 or C-295M and C-27J aircraft respectively to meet the specified requirement. The C-295 and the C-27J aircraft were shortlisted and were subject to a full tender evaluation process.

“Although the Project evaluation was completed on time and was presented to Defence in November 1999, there were considerable delays in announcing a preferred tenderer and much industry speculation that the long running project would not receive funding to meet the project needs,” GPCAT Tasker continued. “ In June Defence advised CASA and LMATTS that it had decided against a further extension of the tender process and that Air 5190 was suspended but not cancelled. Funding for the project was eventually withdrawn and despite this knowledge, both companies were not advised of the decision not to proceed with the project until much later.”

There were estimates that CASA and LMATTS had each spent in excess of $10m in attempting to win the competition, and there had been considerable time and effort put into the project by all concerned.

As that decision loomed WGCDR Tony Bennett was appointed as 38SQN commanding officer with the brief that he would be the last CO of a Caribou squadron. Tony eventually retired in the early 2000s with over 5500 Caribou hours (possibly the RAAF record for pilots), however the aircraft did not.

The unique capabilities of the Caribou, coupled with the sudden dearth of money for a replacement meant that the aircraft would soldier on for another decade, during which it would operate in the Solomon Islands as part of Operation Anode, the RAAF mission in support of the RAMSI (Regional Assistance Mission to Solomon Islands) operations, well as providing famine and tsunami relief in PNG.

With the reduced Caribou fleet numbers it made little sense to keep two separate Caribou squadrons operational, so in 2000 35SQN was disbanded, leaving 38SQN the sole RAAF Caribou operator. 38SQN continued to operate a detachment in Townsville to meet Army support requirements and eventually the decision was made to relocate 38SQN to Townsville in 2008. The plan was to retire the aircraft in 2010 but ongoing fatigue life, maintenance and spares issues meant that it was no longer cost-effective to keep the remainder of the fleet operational and the retirement date was brought forward.

SQNLDR Rookyard explained some of the other problems.

“Over the years the experience levels also dropped. The newer maintainers are taught about new and improved systems, and then they come and work on the Caribou! That is certainly a shock for them. We have suffered in recent times due to a lack of experience.

Fortunately in the aircrew world, our flight engineers have been around for a much longer time. They are also a good measure of changes over the years – over 45 years the wheel has obviously been reinvented numerous times!”

On Feburary 19 2009 then Defence Minister Joel Fitzgibbon announced that the clock would run out for the Caribou at the end of 2009 and that 38SQN would take possession of eight King Airs to maintain the skills base of a core of pilots and maintainers in anticipation of a replacement aircraft arriving as part of Project Air 8000 Phase 2, with a decision planned for the 2012-13 or 2014-15 financial years and an initial operating capability pencilled in for 2014-16, according to the current Defence Capability Plan.

38 Squadron celebrated the end of an era of 45 years of continuous Caribou operations with a colours parade and an old fashioned hangar bash in early November 2009. Around 1300 past and present aircrew, maintainers and support personnel gathered to send the old girls off in style.

In late November, the two oldest surviving Caribou, A4-140 and A4-152, set out from Townsville, captained by CO 38SQN WGCDR Tony Thorpe and his XO SQNLDR Rookyard on their final flights to their new homes at the Australian War Memorial and the Point Cook RAAF Museum respectively. The delivery of A4-152 was also SQNLDR Rookyard’s final flight in the RAAF before retiring.

“If they get rid of the Bou, I’m going with it!” SQNLDR Rookyard had remarked.

The trek southwards included stopovers in the former Caribou bases of Amberley and Richmond, with A4-152 touching down at Point Cook on November 26, while A4-140’s landing at Canberra just after 1.10pm the following day should mark the final flight of a RAAF Caribou. 38SQN’s other remaining Caribou had been flown to Oakey for storage pending their disposal.

Still, that was not quiet the end of RAAF Caribou service as 38SQN was maintaining a contingency availability of two Caribou and crews up until the final hours of 2009, should the aircraft’s unique capabilities be required at any time.

Flying the Gravel Truck

Piloting a big radial engined aircraft these days is an increasingly rare privilege, so most Caribou pilots regard their time on the aircraft with pride and nostalgia. With almost 3000hp (2240kW) available and landing speeds as low as 60kt, the aircraft presented a steep learning curve to any freshly minted pilot. Just learning the complex engine start procedure usually generated loud reports, “duck shooting”, from the exhaust augmenters which would broadcast their beginner’s status across the base and beyond.

Before the advent of GPS pilots were expected to master the arcane mysteries of pilot navigation including off-airways air plotting, the use of drift sights and even navigating by reading the wind speed and direction of the surface of the water at low level. A typical three month conversion course would include circuits, instrument flying using an artificial horizon, airways trainers and airdrop sorties with five different types of delivery methods and parameters to master including the tricky LAPES (Low Altitude Parachute Extraction System) method which involved flying at 1-2 metres above the ground in a landing configuration and extracting a 2000kg load via parachute.

Pilots were introduced to the myriad roles of the aircraft and then its STOL characteristics, first in the Australian outback and then in the mountains of PNG. Interestingly there was no anti-skid fitted to the brake system. Pilots learned the technique of rapid repetitive brake applications on a STOL landing to avoid locking up the brakes. In time, given a 10kt headwind, pilots learned to pull up in less than 500ft from the threshold. With even more headwind the brevity of the ground roll became truly spectacular.
The PNG trainer was always a favourite.

“Operating in PNG is by far the ultimate Caribou job and I have enjoyed the time I have spent up there the most. In 2007 the Caribou was a large player in the movement of rice and other supplies around the Popondetta region when a lot of the villages were cut off by floods. We moved 545,959lb and 352 passengers in two weeks.” SQNLDR RookYard recalled.

For a line pilot there was always there was something different.

Earlier this year I captained an NVG (night vision goggle) mission at midnight and air-dropped seven compacts into a paddock to resupply troops on the ground. The next day I was flying along a beach at sunset at 250 feet above ground level with my window open, and my arm out of the side. The Caribou was the only option for this!” noted FLTLT Ali Torr.

The Caribou remained pretty much the same workhorse that arrived on our shores in 1964. Almost uniquely for a military aircraft there were only minor avionics upgrades including GPS, an ADI and a NVG fit-out. In RAAF service, it was never equipped with either autopilot or weather radar so the last pilots to fly it needed virtually the same skill-set as the first. Therefore there is a bond between all who flew this unique aircraft over the years.

Perhaps the only major change in crewing has been the inclusion of the fairer sex into latter day Caribou operations. Possibly the best metric of this is the fact that 38SQN had four PNG captains when it wound down Caribou ops. Three of them, including the XO, were female.

The Caribou lasted for so long in the RAAF because of its unique set of capabilities. Its service to the nation is unquestioned and perhaps best summed up by the man charged with the responsibility of seeing the aircraft into history:

“The decision to withdraw the aircraft from operational service was not made lightly, noting that even after 45 years the Caribou continued to provide a unique operational capability. Ultimately this was a decision that supports the demands and capability growth of the developing wider Air Force,” reflected WGCDR Thorpe.

The Caribou has touched the lives of so many people, from the battlefields of Vietnam, the highlands of Kashmir or Papua New Guinea, to the flooded landscape of the Australian outback. It has been an ever present workhorse for the ADF and the Australian community.

The Caribou has a distinguished place in history and a special place in the hearts of everyone who has been associated with the aircraft.”