Electronic Weapons: Lifesaving Flight Control Software

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October 11, 2016: In 2014 the U.S. Air Force addressed several, frequently fatal, problems fighter pilots encounter in training or combat; disorientation and blackouts. High-speed maneuvers sometimes cause blackouts and loss of control of the aircraft. Disorientation is possible at any altitude but is most common when at low altitudes. Accidentally hitting the ground while flying low or in bad weather has long been a problem. The solution was new flight control software, much of it based on of decades work on similar software for commercial aircraft. There are two new systems now in use.

Auto GCAS (Automatic Ground Collision Avoidance System) will automatically take over the controls and return the aircraft to flying straight and level if it detects imminent collision with the ground. Versions of his capability has been used in commercial aircraft for decades. Basic versions simply produced an audible “collision alert” so the pilots could take appropriate action. But there were cases where pilots, commercial or military, were distracted and ignored the alert until it was too late. Auto GCAS will automatically kick in if the pilot does not take action. For fighter pilots, especially those in single seat aircraft, this has already proven to be a lifesaver in combat or training when the pilot passed out or became disoriented from high-gravity situations. In less than two years of operations Auto GCAS has saved the lives of four fighter pilots, including at least one in a combat zone.

PARS (Pilot Activated Recovery System) is often referred to as a panic button for pilots who find themselves disoriented and possibly moving in a dangerous direction. This is a common problem in bad weather and at night. PARS will, one activated, operate in a similar fashion (and using some of the same hardware and software) as Auto GCAS to return the aircraft to flying straight and level. It’s difficult to say how many lives PARS has saved so far, but pilots flying in difficult conditions (as in the Middle East and Afghanistan) say it makes work a lot less stressful.

Before Auto GCAS fighting pilots, especially those in training, often died because high G-forces caused them to pass out unexpectedly. In training new pilots are taught how to handle these situations but while making a high-speed turn at high altitude a tiny miscalculation can cause an unexpected blackout. Fighter pilots are equipped and trained to deal with handling up to at least 9 Gs. But some of these methods require the pilot to contract abdominal muscles and take a deep breath to maintain consciousness. It is believed that many deaths were the result of the pilot forgetting to tighten up and take a deep breath, as he was concentrating on the complex, and high-G, maneuver he was undertaking.

G (gravity)-forces are not a problem for most other aircraft, but are a critical shortcoming for modern fighters. Since the 1990s more powerful engines and computer assisted flight controls have enabled fighters to not only execute increasingly violent maneuvers, but to do it more quickly and in different directions. Because of this, medical doctors have gotten involved in the design of these aircraft, because the flight control systems have to be designed so that the aircraft cannot easily make a maneuver that the pilot cannot handle.

Since the 1960s a growing number of aircraft have been capable to executing maneuvers, usually sharp turns while moving at high speeds, that create a gravitational force (G-force) that causes the pilot to blackout. At first it was believed special flight suits were the answer. These use small liquid or air filled bladders to help prevent blood from rushing from the brain, and causing a blackout. But even with the G suit pilots found they still had to use their abdominal muscles and a deep breath to avoid blackout.

Since the 1980s computer assisted flight controls have been developed that prevent the pilot from executing a maneuver that would exceed 9 Gs. But as aircraft become faster and more agile, there are more directions the aircraft can be going while pulling lots of Gs. Pilots now have to worry about neck injuries, if they execute certain maneuvers without positioning their head just so. Just another thing to keep in mind during a dog-fight, in addition to the gut clench and deep breath.

For decades now, fighter pilots have had to spend a lot of time in the gym, in order to be able to handle the G forces, even with the G suit. Otherwise, pilots can get groggy, or even pass out in flight, as well as land with strained muscles. All this gym time is one reason fighter pilots are such chick magnets.

 


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