Canberras join Fireforce
SEVEN DAYS AFTER FIRST USE of Alpha bombs in Mozambique, Randy du Rand and his navigator, Flight Lieutenant Terry Bennett, got airborne from Buffalo Range in support of the Repulse Fireforce. This came about because Randy was keen to gain operational experience with the new weapon system and I needed plenty of feedback on bomblets’ performance. The idea of deploying a Canberra to Repulse was greeted with enthusiasm by Tol Janeke because it had become abundantly clear that, as expected, ZANLA’s main thrust was coming through the Gaza Province of Mozambique.
Under guidance from a K-Car, a cluster of fifty Alpha bombs was delivered and all landed in the base from which eight CTs had moved immediately upon hearing the approaching KCar. Squadron Leader Graham Cronshaw in the K-Car and the Army callsign who had called for Fireforce reported being thoroughly shaken by the sight and sound of the Alpha strike, even though it was only one sixth of a full load.
The Army callsign swept through the CT base and confirmed shrapnel had saturated it. Although the bombs had killed no CTs, who were a short distance away, the effect of the strike so unnerved the eight members of this group that they surrendered without a shot being fired. Randy remained the heavy arm of Fireforce for a while and was able to prove the Canberra’s ability to bring quick and accurate strikes to bear wherever they were needed, because K-Cars could place down reference markers with their new smoke grenades. Having satisfied himself, Randy rotated each of his squadron crews to Op Repulse to gain experience.
During November a ZANLA base in Mozambique close to the border was positively identified by Canberra photo-recce. An operation similar the one at Mavue was planned but, due to good features around the target, three Canberras led the strike for maximum surprise. They made the attack from 500 feet at a release speed of 300 knots. The strike went in just before the arrival of the heli-borne and para force and all the bombs landed on target as planned. Instead of arriving over a subdued enemy however, the helicopters faced a hornet’s nest of alert and angry ZANLA firing many small arms and heavy AA guns.
Following some brave action to silence the AA guns, particularly by Mike Borlace, troops eventually overran the base and found the reason for the Canberra’s failure to provide any subduing effect. All but two of the Alpha bombs had broken through a crust of sand and buried in thick wet clay before exploding harmlessly below the surface. The whole target area was covered with black bomblet craters. Two bomblets that struck trees caused the airbursts that accounted for only the three ZANLA killed in the airstrike.
There was deep consternation at Air HQ and within my project team. We had not foreseen this problem, which was entirely my own fault. I knew how similar ground conditions in the Zambezi Valley had presented the Army with serious vehicle movement difficulties. Following heavy rains, such as had occurred in the area of this target, the softened sand crust above damp clay yielded without warning. When this occurred, vehicles sank to their axles and other vehicles attempting to pull out a stricken one usually ended up in the same mess.
Although I should have foreseen the problem earlier, I was certain that the correct combination of delivery height and speed would prevent further failures, no matter the nature of surface. So we immediately set about finding a test location close to Salisbury where sufficient clay, hard ground and water existed in close proximity to each other. The place we selected was a small dam at Inkomo Range. We used concrete Alpha bomblets, knowing that live ones would perform better.
Randy du Rand and Terry Bennett flew the same attack profile they used on the failed attack and dropped a cluster of fifty concrete Alpha bombs. They were bang on target and those that struck dry ground recovered into flight normally. All the bomblets that landed on water and most that landed on sand-covered clay disappeared below the surface. Those few that struck sand over clay yet found their way up to the surface were coated with a thick layer of gluey black muck.
The next delivery was made from 400 feet at a ground release speed of 300 knots, giving marginally improved results. Delivery height was then stepped down to 300 feet, again at 300 knots. Most of the bomblets bounced back into flight from mud and water, though some of the units that landed in mud were so thickly coated that their recovery was way too low and sluggish. Three runs were then made at 300 feet at 350 knots. All bombs bounced into flight though the ones from clay did not rise as high as from water and normal ground.
From then on 300 feet was the preferred attack height at an attack speed of 350 knots, which still provided adequate separation between detonating bomblets and the aircraft. However, the increased attack speed presented a major problem in terms of airframe fatigue factoring. Fortunately the Canberra could accelerate from 280 knots to 350 knots very rapidly, which minimised the time spent at attack speed. Nevertheless the high fatigue factor applied for this speed converted three minutes to something in the order of one hour of expended airframe life.
Inevitably with so many bomblets being dropped, there were some unexploded units (UXBs). A total failure rate of around 3% was either caused by technical problems or by bomblets passing through vegetation that progressively decelerated them to such an extent that they failed to realise the 100G-impact force needed to activate pistols. All bomblets were painted red to simplify UXB collection and soldiers had been advised that they were perfectly safe to handle and transport. So it was with some alarm that they learned of a UXB that had killed two African children and wounded another.
I immediately went to the scene of the tragedy and noticed that the bomblet in question had exploded on a solid flat section of granite with large boulders around it. Near the point of explosion, I saw red paint marks at different places on the flat rock and came to the conclusion that the children had been throwing the bomblet from the boulders above.
The surviving little boy in hospital confirmed this. He was lucky because, being fearful of his friends’ attempts to break the ‘ball’ open, he had watched from a distance as the others climbed small boulders to throw the bomblet onto the flat rock. His friends could not crack the unit open so they went up onto the highest rock. The bomblet pistol received the necessary G load and bang went their lives.
Yellow Submarine
SELOUS SCOUTS WERE COMMITTED TO using noisy vehicles and experienced a variety of difficulties in their attempts to render the rail line from Maputo to the border town of Malvernia inoperable. Then, whilst they were working on this difficult task, they noticed that a yellow Alouette III came up the rail line from Maputo and turned northwards along the Cabora Bassa power-line. Radio intercepts on FRELIMO’s radio network soon established that this was a regular run for a Maputo-based engineer to inspect a section of the power-lines running from Cabora Bassa to South Africa. Intercepted messages also showed that all FRELIMO posts were told not to shoot at the yellow Alouette. Ron Reid-Daly approached Norman Walsh to see if Air HQ would consider painting one of our own Alouettes canary yellow so that rail and train destruction parties and recce teams could fly unchallenged directly to their selected targets. Norman sorted this out without delay and John Blythe-Wood flew the aircraft, nicknamed ‘Yellow Submarine’, from its secret covers at New Sarum for a night flight to the Selous Scouts forward HQ. The rail wreckers enjoyed a trouble-free period until FRELIMO finally tumbled to what was happening.