23 Mei 2011

Training to be Pilots in RSAF

23 Mei 2011

Like a giant upward catapult, the Ejection Seat Trainer (EST) propels pilots skywards at 4Gs to help them master the correct posture for ejection. (photo : Cyberpioneer)

Extreme speed and altitude does strange things to the human body, as I found out during a visit to the Republic of Singapore Air Force (RSAF) Aeromedical Centre (ARMC) and Flight Simulation Centre (FSC) recently.

While this would not worry land-lubbers like me, they are real everyday concerns to RSAF pilots. For example, pilots turning at speed while executing aggressive airborne manoeuvres are subject to extreme gravitational forces. These G-forces make them prone to blacking-out due to what aeromedical experts call "gravity-induced loss of consciousness" (GLOC).

To combat GLOC, pilots are taught to execute the Anti-G Straining Manoeuvre, which requires the pilot to tense muscles and take short breaths to prevent blood in the head and torso from flowing into the body's lower extremities, in order to maintain consciousness.

This is where the Human Training Centrifuge (HTC) housed in the ARMC comes in: it replicates the G-forces which a fighter pilot has to endure in a safe and controlled environment. Sitting in a circular structure, the HTC is anchored on one end to the floor. From that anchor, which is also its turning axis, a 7.5m arm extends outwards before ending in a gondola where a pilot undergoing training would sit.

The machine takes just a few seconds to hit 9Gs and that is the magic number when it comes to flying fighter aircraft as it is also the maximum amount of G-force which most pilots will ever encounter. All RSAF fighter pilots are required to return to the HTC once every three years to experience 9Gs for a maximum of 15 seconds, in order to continue flying. In comparison, a roller-coaster generates 4Gs at most.

The advanced Spatial Disorientation Trainer trains pilots to trust their aircraft instruments rather than rely on their own senses during flight. (photo : Cyberpioneer)


For an idea of how that feels, imagine a weight nine times your own body weight acting on every inch of your body. "At 9Gs, every movement becomes significantly more strenuous because the pilot has to fight the weight acting on him and still control the aircraft," said Major (MAJ) (Dr) Timothy Teoh from the ARMC.


In addition, the lack of oxygen at extreme altitudes can turn pilots, otherwise known for their sharp reflexes, into clumsy clods. As part of their once-in-three-years refresher, the pilots experience dulled reflexes and cognitive ability when exposed to atmospheric conditions replicating those at 25,000 ft (7,620m) in the ARMC's hypobaric chamber. Simple arithmetic usually solved in mere seconds are met with puzzled looks on the pilots' faces under these conditions, and a child's hand-clapping game becomes a farce as pilots miss each other's hands by a mile.

Though these symptoms are amusing to watch, hypoxia's effects on pilots are insidious. "The untrained person would not even know it when he or she is suffering the effects of hypoxia," said MAJ (Dr) Teoh.

The HTC is designed to let pilots experience the massive G-Forces they have to endure during aggressive aerial manoeuvres in a safe yet realistic environment. (photo : Cyberpioneer)

Luckily, there are physical sensations which hint at the onset of hypoxia; such as numbness and light-headedness. "Every individual reacts to hypoxia differently, which is why it is important for the pilots to come to the Hypobaric Chamber and learn to recognise the onset of hypoxia," said MAJ (Dr) Teoh. The pilots also go through the latest safety drills at the same time.

Imagine having to turn when your every inch of your body is convinced that the turn will lead to a crash. This is where RSAF fighter pilots exercise supreme discipline, controlling their aircraft based on what their in-flight instruments indicate, rather than what their own senses tell them.

The Advanced Spatial Disorientation Trainer is what the RSAF uses to remind its pilots to trust their instruments. It is a full-motion flight simulator to create actual in-flight conditions, training aircrew in procedures and techniques that enable them to recognise and address problems of spatial disorientation.

The interior of the Hypobaric Chamber at the ARMC allows pilots to recognise the symptoms of hypoxia which can impair judgement and reduce psycho-motor coordination. (photo : Cyberpioneer)

Like the HTC and Hypobaric Chamber, RSAF fighter pilots are required to re-visit the Spatial Disorientation Trainer once every three years to keep themselves up to date with the latest training doctrines.

According to MAJ (Dr) Teoh, pilots eject from their aircraft at speeds generating about 12Gs. In order to do so safely, they must adopt a tucked-in posture, keeping their spine straight. To learn to do that, the Ejection Seat Trainer (EST) is the machine to go to. Although it only generates about 4G, its realistic set-up means pilots can practice their ejection postures safely.

"The intention of the EST is to train our pilot on the correct posture to adopt if they should ever need to eject. That's also why we only program the simulator to do 4Gs," said MAJ (Dr) Teoh. Unlike the other three simulators, the EST is a yearly requirement for fighter pilots.
The FSC also features the Operational Flight Trainer (OFT), a dual-seat cockpit simulator equipped with an exact replica of the cockpit of the F-16D fighter aircraft.

I took my seat at the front and behind me was Captain (CPT) Quek Kwan Yi, a flight instructor from 140 Squadron. While he took control of the aircraft during its take-off, he soon handed the controls to me.

Cyberpioneer journalist Hong Tat trying his hand in the F-16C/D fighter aircraft Operational flight Trainer. It wasn't easy, as he found out. (Cyberpioneer)

Very quickly, I realised that the controls were more sensitive than I thought they would be: an imperceptible nudge to the left on the stick translated to a full left turn by the aircraft. A few more yanks at trying to rectify my error later, I found myself flying upside-down. I suspect CPT Quek was chuckling at the back at my ineptitude but I was too pre-occupied with levelling the aircraft to bother.
After a bumpy landing, we went to the nearby Instructor Operating Station where I learnt that the OFT is an ultra-realistic simulator system which can generate up to 200 enemy forces for tactical scenarios to test the pilot's reactivity and adaptability to unpredictable situations.

I was feeling good about myself until the instructor, who had been generating the scenario which I was flying in a few minutes earlier, casually mentioned that I was flying in a zero wind-speed environment - one of the easiest scenarios to fly in.

Ego properly deflated, I am convinced that flying should be left to people who didn’t have two left feet like me. If you think you can do better, visit the RSAF Open House 2011 at Paya Lebar Air Base from 28 to 29 May, where you'll be able to catch a ride in the OFT!

(Cyberpioneer)

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