Flock of Birds
From memoirs - Tropical flight testing of a revised ECS system in a Canberra B20.
Birds caused me some problems at Butterworth. I wanted to test the ECS at low altitude and high speed. Whilst at about 400 kts at 200 ft over the sea off the island of Penang, I noticed a little black spot grow rapidly in size directly along the aircraft flight path. I only had time to pull a little elevator before the bird impacted with a huge thump on the aircraft's nose. I pulled up losing speed trying to assess damage. At the speed even a small bird could do considerable damage and this one had been fairly large. We returned immediately to land at Butterworth.
Fortunately, the bird had impacted along one edge of the forward bomb aimer's window. This was armoured glass and had taken most of the shock. A deep gouge had been made in the perspex surrounding the glass window. We were lucky.
A few days later I had the test Canberra fuel load at maximum when I started a take-off at dusk from the 8,000 ft runway at Butterworth. As we accelerated towards lift-off, I saw a very dense flock of small birds rise up off the runway some 600 feet away. Appearing like a small black cloud the birds flew upwards and I thought that I would probably miss most of them if I held down, on or close to, the runway. But the black cloud, disturbed by my approach, apparently decided to try to go back to ground.
I had now lifted off and had a split second to decide whether to put the wheels back on the runway and abort the take off. But there was hardly enough runway left in which to stop the heavy aircraft. Were I to fly through the birds, I would likely lose both engines. What a predicament! Instinctively, I pulled back hard on the controls in an attempt to rise above the main concentration of birds. The aircraft shuddered, at the low speed, as I felt for the limits of the lift from the wings. This occurs just before wing stall which was to be avoided at all costs.
The navigator, behind me, was unable to see forward so I advised him and the tower by calling out,"Avoiding birds" as I tried to also turn a little to the right. The black cloud rapidly became a multitude of dots as I squashed into the outer fringes. There was a staccato of little bangs and the left engine wound down a few RPM before recovering. We had made it. I pulled a substantial reduction in power on both engines in case there was damage, left the undercarriage down and flew a tight circuit to return to the runway as soon as possible. On the landing run, I could see dead and injured birds scattered on the runway.
There was evidence of birds having hit the engine compressor guide vanes and many birds and pieces were pulled from the undercarriage and wheel wells. We had not been fast enough for the small birds to have damaged the aircraft skin. The fire crew picked up 58 birds from the runway.
Inspection and ground running of engines did not point to any damage so we launched again the next evening after a vehicle had flushed out any birds from, and adjacent to, the runway. The flight was to have been for about 4 hours at maximum altitude to permit aircraft temperatures to stabilise. After 3 hours, we were too cold to continue and I returned to lower altitudes and warmer air.
The trials had shown the inadequacy of the revised Environmental Control System (ECS) system so it was now up to the engineers to try again.