I just came across this terrific article on Dave Cohu in the Press, dated 14th of August 1971:
Topdressing pilot’s 15,000 hours in the air(By MAX C. AVERY)
It is 5.15 o’clock on a crisp April morning. The alarm clock shrills, but the pilot is already awake. He is used to waking before the clock begins its clamour. In 20 years of waking early, whether it be 3 a.m. in the summer or 6 a.m. in the winter, he usually beats the bell. But he
After stilling the noise he climbs out of bed and makes himself a cup of tea. By the time he switches the radio on for a weather forecast he is taking more interest in the day.
Twenty-eight years ago, David Cohu, of Mount Maunganui, first took an active interest in aviation. There was a war on. It was 1943, and the Allies were beginning to drive the Japanese back across the Pacific. Young Cohu wanted to help so he joined the R.N.Z.A.F. His first aircraft was a Tiger Moth. After bringing it back in one piece from his first solo he went on to advanced trainers, and finally was posted with 17 Squadron to the Pacific where he flew Corsairs—stubby bent-wing fighters with huge radial engines. It was in Corsairs that Dave Cohu first learnt an air-to-ground technique. He did three tours in Corsairs, engaged mainly in low-level bombing and strafing, working from leap-frogging ground bases. He only saw one Japanese aircraft in the sky.
An old team After hearing the forecast the pilot takes a look out the window. The sky is a little overcast, and although it is calm outside some high scudding streaks of cloud, tinged with a pre-dawn pink, by the pre-birth of dawn, promise some wind in not too many hours. He packs a thermos of tea and some sandwiches, but eats no breakfast. Never has. On the way to the aerodrome he picks up his loader driver. They have had nearly 20 years together—a unique association in an industry where loader drivers usually aspire to sit in the pilot’s seat, and regard their job as a stepping stone. Today they are about the best team in the business.
At the hangar they wheel the Fletcher FU24 out. The topdresser is caked with superphosphate (and a dozen other powdered chemicals) on its underside. It looks like a workhorse—and it is. The pilot walks carefully around the machine, pushing and pulling here, moving the flaps and tailplane. He knows the value of checks. He has had pieces drop off before. Dave Cohu’s instructors taught him carefully and careful flying was to take him through three years of active service with the R.N.Z.A.F., and three years with the R.N.Z.A.F. in peace-time, without a serious mishap. Sure, there was a risk. There must be, when you dive a Corsair spitting cannon fire at a Japanese anti-aircraft battery which is firing back only a little slower. But Dave Cohu was lucky. Often shot up, never shot down.
Full throttle Out on the tarmac the pilot presses the starter button. The 300 b.h.p. flat six Continental turns over a few times and roars into life. Inside the cockpit the pilot dons ear muffs to shut out some of the noise. They do not do much good, but he thinks they may save his hearing from further damage.
The FU24’s airframe shudders and shakes as the pilot runs through the engine check. In 20 years of topdressing flying he has found an extra minute spent checking an engine on the ground can give a pilot many years of life. On the jump seat beside the pilot the loader-driver settles back comfortably. For 20 years he has trusted the pilot’s flying, and today he will still fly anywhere with him.
Out on the tar-sealed runway; regulations. The pilot would rather use the grass beside it. Full throttle and the FU24 bounces skyward, exhausts crackling down through 1000 ft of airspace to stir some of the population restlessly awakening.
Dave Cohu’s introduction to aerial topdressing was accidental. He had stopped a dog fight up the Coromandel' Peninsula (in the North Island) while on leave and had been bitten in the process. Dave was on his way to the doctor when he saw a Tiger Moth being used to sow superphosphate. Not having seen an aircraft being flown like that, Dave Cohu stopped the car, jumped the fence to watch. The super-begrimed pilot soon made his acquaintance and offered him a job. “Do you think you could land one of these on a 500 ft grass strip like this?” he asked.
Dave, who had been sweating out some landings on 5000 ft sealed runways with Mosquitoes, doubted it. Anyway, he had applied to join the R.A.F. On April 3, 1951, Dave Cohu took a temporary job aerial topdressing while awaiting his passage to England and jet fighters. Today, just 20 years, 15,000 hours of agricultural flying and 140,000 tons of sown super later, he is one of New Zealand’s three senior topdressing pilots.
13 tons an hour The farm airstrip appears below, and the FU24 bounces over the rough turf to the pile of super and the loader. The pilot knows the farm well. The farmer is an old customer. Within minutes the loader driver, who once shook bags of super into a Tiger Moth on the same strip, has the first 15cwt in the hopper and the FU24, sagging under the load, is roaring across the turf, full throttle, full boost, all stops out. The operations manager expects about 13 tons an hour sown, and the farmer, who is paying $1.48 cents a minute for the service would like more. The aircraft is away four minutes then comes low on to the strip, thumping along, engine popping and backfiring. A burst with the engine to swing her around, eight seconds stopped to take on another 15cwt, and away the pilot takes her. So the day’s routine has begun, load and sow, load and sow, with the smooth backing and filling of the loader, the roar of the aircraft engine, the clouds of super and dust with each take-off.
Nearly an hour later the pilot has sown 10 and a half tons of fertiliser. Fairly long hauls from the roadside strip to the back of the farm and a rising cross-wind leave little chance of getting the chemical on at the optimum 13 tons an hour. After a brief conference with the farmer and loader-driver he is off to the next job, yawing the empty FU24 down the strip.
Dave Cohu’s first agriculture aircraft was a Tiger Moth. He developed a great respect for the little biplanes, particularly after he crashed one and walked away unhurt. The crash cause was a typical one in the early days of aerial topdressing —a pilot caught with a load of basic slag in a blind gully, and not enough lift to clear the ridge. Basic slag runs out of a hopper slowly, and with no load dumping safeguard the Tiger went in.
Clawing for height The situation is a little better at the second farm than the pilot first thought. He holds up two fingers, and the loader driver dumps an extra two hundredweight of fertiliser in the hopper, which makes it 14cwt after a 12cwt trial run. Away goes the Fletcher. Downhill with a tail wind.
The precipitous drop away from the end of the runway is a blessing. Full throttle, 20 degrees of flap (or maybe just a little more) the FU24 claws its way out over the gully, 55 miles an hour showing on the airspeed indicator. The plane drops stone-like for maybe 50 or 100 ft and then speed picks up, and with it comes a little altitude. The pilot changes his concern from staying airborne to heading for the sowing area. On the next run he holds up one finger. Another hundredweight. The wind is getting stronger, but the pilot want to get as much super on as possible before he stops. In those 20 years, he remembers, he has flown in worse conditions—and in less suitable aircraft.
Dave Cohu has carried on for longer than any other agriculture pilot in New Zealand. He admits he takes a calculated risk most times he opens the throttle, and he knows that as he continues to fly he must expect to have what he terms "incidents." He says: "You are lucky if you get away with it unlucky if you don’t” He has his regrets. He should have made a serious attempt to get into airline flying many years ago. But it is too late now. When he flew his first Tiger Moth, Dave Cohu knew he should play the game, for a few years, make a pile and get out “Topdressing used to be a fairly lucrative game. We were well paid 15 years ago; but today it’s just another job. It should have been a stepping stone to somewhere.”
A near thing A few more runs with 15 cwt of super aboard. The pilot is getting through the work. The loading operation is silk-smooth. Only the wind is likely to change—and it does.
Forty-five seconds off the strip with 15cwt, and the ridge ahead is too high. Full throttle, but the altimeter stays steady. The wind, now on his tail, is no help. The gully is blind to the left, and there are trees to the right. The situation is classic. So the pilot does what he has done many time before. He pulls the emergency dump lever. For a long second it seems as though nothing will happen. The ridge appears to tower over him—and then the FU24 responds as though she is in an express lift. The 300 b.h.p. hauls him high in the sky, way above the ridge. But there is a film of moisture on his brow, a slight shake to the fingers, a funny feeling in his stomach as he banks the plane back to the strip.
The next run is still with 15cwt on board. Unconsciously his hand stays close to the dump lever on the take-off, and for the next few take-off runs. And he watches the altimeter very closely. Because the pilot has crashed in a Fletcher before. He knows exactly how it feels, and how it sounds when an FU24 ploughs into the ground, how the instrument panel and canopy slam toward you just before the world goes crazy and you become disorientated in a cruel buffeting of sound and movement.
Jaundiced eye Two crashes and several forced landings because of aircraft component failure and other reasons; farm animals which career out during landings' and take-offs; jittery nerves as you sit sweating in the cockpit after an "incident,” thinking of the 158 agricultural pilots in New Zealand, and the 70 who have lost their lives since the industry began. The pilot knows it all. He was there.
Twenty years on Dave Cohu looks at agriculture aviation with a jaundiced eye. He still likes the job, make no mistake about that. But salaries today average only $5500 a year. $5500 for bending a $25,000 aircraft over hilltops, between trees and down gullies for six days out of every seven; $5500 for increasing New Zealand's primary produce overseas earning potential by about one million dollars per pilot per year. David Cohu will fly as long as he can. "As long as he can” will be determined by the economy of the industry, his age, and "incidents.” Until one of those factors becomes positive it will continue to be a case of full throttle and 20 degrees of flap (or maybe a little more).
See the photos here paperspast.natlib.govt.nz/newspapers/press/1971/08/14/12
