Sacrifice of jet heroes
QUESTION The description of the death of Lieutenant Commander Simon Scott Thomas in a Navy Sea Vixen stated that out of the 145 aircraft built, 54 were lost in accidents and 55 aircrew were killed in the 13 years of the aircraft’s front-line service. Why was there such a high rate of loss when none flew in combat?
The De havilland Sea Vixen was an allweather high and low-level interceptor in service with the Royal Navy from 1959-72.
During its time in service, one of its main requirements was an ability to attack enemy ships by day or night for which a tactic known as Night Glow Worm Attack was used. It was this that caused the loss of many aircraft and aircrew, though there were other reasons.
A division (four aircraft) would attack a splash target towed by a ship during the night. The splash target produced a large plume of water, which then became the aiming point for the subsequent attack.
The Sea Vixens were armed with four 3in Glow Worm illuminating flare rockets and pods of 2in high-explosive rocket projectiles, and the general idea was for the attack leader to illuminate the target in preparation for the attack by the remaining three aircraft. This type of flying required nerves of steel and constant practice.
high and low-level flying at speed over the sea at night, along with the high G-force during these manoeuvres, led to a phenomenon known as spatial disorientation: pilots became unsure of their position in relation to the sea. In addition, Glow Worm flares were notorious for not functioning fully and this caused further confusion as to where the target was.
A combination of manually locating weapons switches in a dark, confined cockpit while wearing a pressurised flying suit, along with keeping in formation during high-speed turns was a cocktail for pilots to become disorientated.
By the very nature of the attack, the flares caused the pilot to see a line of light descending 45 degrees to the left and it was discovered that the mind accepted this as the true horizon, resulting in the pilot then banking 45 degrees to the left, mistakenly thinking he was in level flight.
Consequently, when the aircraft was pulled out of the dive at 450 knots and 500ft to reform, the aircraft would fly into the sea, resulting in the loss of the aircrew.
As technical advances were made, the Glow Worm flares were discontinued as a result of Lepus flares (each equivalent to several million candlepower) being brought into service.
A dedicated Sea Vixen illuminator would light the target as if it were daylight, thereby allowing the remaining three aircraft to make their attack without any doubt as to the orientation or position of the target. The use of Lepus flares ended fatalities during this type of attack.
Other causes of fatalities were engine flame- outs during launch from a flight deck, and landing a heavy aircraft on a comparatively small deck, necessitating the deployment of a nylon crash barrier after an aircraft had developed a fault in flight.
Andrew M. Wade, Peterborough.
QUESTION What proportion of an adult fare do bus companies receive when they accept a senior bus pass?
GOVERNMENT legislation requires bus operators to be ‘no better and no worse off’ as a result of accepting passes. It pays a sum annually to each local authority which is intended to reflect this, and which councils then distribute among operators.
Passengers using passes can be divided between those who would travel anyway and whose fares are lost, and travel newly generated by the offer of a free ride.
The problem is to identify the proportions of each. An average single fare is calculated and the authority pays operators an agreed percentage of this, multiplied by the number of journeys made.
The percentage varies widely and has been falling as councils struggle with reduced funding. For example, while the ‘reimbursement rate’ in Scotland is around 60 per cent, in North Yorkshire it is 28 per cent.
In rural areas particularly, pass-holders can make up a high percentage of passengers and it’s possible for even a full bus of passholders to be loss-making.
As a result, some long- established businesses have been forced to close or drastically reduce services (this might ‘ring a bell’ with readers in Cornwall).
There is the view that where a bus is already running and has spare seats, it costs no more to carry pass-holders, so operators do not need to be reimbursed. But this ignores the loss of income from existing passengers, but there can also be higher costs from the new passengers generated.
Sometimes it is necessary to run a larger bus with higher fuel consumption; but carrying more passengers and checking their passes can slow down the service and require more buses to run.
David Holding, Chester Moor, Durham.
QUESTION In Wolf Hall, when the young Thomas Cromwell accidentally picked up a hot piece of metal, his father advised him to cross his wrists because ‘it confuses the pain’. Is this a recognised pain relief technique?
THIS ancient wisdom might just be true. In 2011, Giandomenico Iannetti, professor of neuroscience at University College London, and colleagues gave 20 volunteers a series of increasingly painful ‘jabs’ to the back of one of their hands using a laser, each pulse lasting eight to 12 seconds.
In half the experiments the group received the jabs with palms face down on a desk. In the other half they crossed their arms over one another on the desk. Brain responses to the pain were measured through electroencephalography (EEG); but they also rated the pain on a scale from zero to 100.
The results from EEG and participants’ reports revealed that perception of pain was weaker when the arms were crossed.
Iannetti concluded that placing one’s hands in unfamiliar spatial positions relative to the body confuses the brain and disrupts the processing of pain messages. ‘You get this mismatch between your body’s frame of reference and your external space frame of reference,’ he said.
According to the researchers, this discovery could lead to new clinical therapies to reduce pain that exploit the brain’s way of representing the body.
Dr Ian Smith, Cambridge.