At great risk of sounding boring or repetitive, I should like to say, again, that when one is involved in aviation maintenance there is only one way to do things and that is the right way.
There are no ‘ifs and buts’, there is no negotiation or discussion necessary and there is no such thing as ‘it will do’!
Quite apart from the number of injuries and fatalities to passengers and crews due to aircraft making big black smoking holes in the ground, there are also risks involved with maintaining aeroplanes.
Time and time again I have said to students taking part in all sorts of courses, “Rule 1: Look after yourself.”
Sadly, this advice tends to be disregarded. Primarily, I suspect, because most people believe that accidents happen to other people, they forget that, to everyone else you are the other person!
On my ‘Facebook’ page [http://on.fb.me/nDwHMO] I have given an example of what happens when the appropriate safety precautions are not taken. There is also a mention there that two people a year, on average (I am told) are sucked into jet engine intakes.
The number of people who are struck and killed by propellers and tail rotors is significantly higher.
How does this happen? Why does it happen?
For many years the makers of propellers and various Aviation Authorities – the CAA (UK) not least among them, have attempted to discover the magic paintwork that will show a propeller up even when it is spinning.
They have failed. Without exception.
The fact is the propellers become invisible when they are rotating at any rpm that becomes inimical to human health (Translates: ‘lethal’).
I spend much time emphasizing to students that if they cannot see a propeller it is very dangerous. Very. This was even stated clearly in “A Simple Guide to Understanding Jet Engines” on Page 59 with a sad example given.
The air rushing into a gas turbine intake is also invisible. There is a famous incident on a US aircraft carrier (USS Theodore Roosevelt, I do believe) where an airman was sucked into an A-6 Intruder intake and survived. He survived because his helmet came off and smashed the compressor blades before his head arrived on the scene.
He was lucky. Extremely lucky. He was also foolhardy.
Propellers and air rushing into intakes are both invisible. The movement of air from one place to another is unstoppable unless you are aerodynamically shaped to permit the flow of air to slip past.
Most people, however, tend to wear clothes when working.
“A Simple Guide to Understanding Jet Engines” Page 131, qv.
The primary cause of these accidents is somewhat deeper. It is invisibility and the inability of the human person to fight the movement of air which creates the accident but there is something much more sinister that creates the situation!
Mindset.
We are, all of us, victims of compulsion and impulsion. Every one of us has pressure applied to do the job quickly. We understand that aeroplanes only make money when they are flying – on the ground they soak up money like a dry sponge.
There is constant pressure on us all to get the aeroplane back up in the air as quickly as possible, that there are schedules that must be kept.
Combine that with the idea that “familiarity breeds contempt”.
We adopt a laissez faire attitude, a feeling that ‘nothing ever happens’ or that the risk has been overstated (by people like me!).
But accidents happen.
“An Air New Zealand spokeswoman said the engine (RR-Allison T56) was sitting on a stand without propellors (sic) attached and was not affixed to a plane (C-130) at the time of the accident.”
A 51 year-old mechanic was sucked into the intake and died.
It is possible that he did not get ‘chopped up’ but his body, in blocking the intake, created a huge depression that damaged his lungs. This must have been, necessarily, at low power because the propeller was not installed.
Low power - and yet...
This is a turbopropeller engine that develops around 6000HP. Low power? Still significantly higher than your Ford Focus engine!
It has something in common with a Ford Focus - it is NOT a toy!
Careless? Yes. Should he have known better? Yes.
Ask yourself ‘how did it happen’? Try to go through it in your mind. Ghastly, isn’t it?
Most people believe that accidents happen to other people, they forget that, to everyone else you are the other person!
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