Landing: The evolution of avionics
How do pilots know when they need to start descending, or where the airport is? It turns out there is a whole host of electronics and instruments onboard planes that give pilots critical information. These instruments are especially impressive in the cockpits of fighter jets. Izzie Clarke spoke to Terry Holloway, Managing Director of the Cambridge Aero Club. What exactly are avionics?
Terry - Well avionics is a wide range of electronic and electrical equipment, which encompasses communication, navigation, a flight management system, an autopilot, in the case of military aircraft weapons systems management, and avionics are in satellites as well, global positioning systems accurately guide you to where you want to go to.
Izzie - Okay, so what instruments would you have found in the cockpit of a fighter plane from World War One?
Terry - Very little, you would have had an altimeter which would have told you approximately how high you were. They weren't particularly accurate. And you would have had a compass which might have told you generally which direction you were going in, but for most World War One fighter pilots perhaps the Sun and its relative position to the time of day might have been more useful than that compass.
Izzie - So how did that all change after World War One?
Terry - Scientists and people involved with aeroplanes always tried to make advances in technology and none more so in trying to communicate with the ground, and to navigate, and get from A to B. The autopilot was a great invention. Strangely, the first autopilot was demonstrated in 1914 a very long time ago, actually before the Royal Air Force was formed.
These days if you're flying in an aeroplane the pilot doesn't really touch the controls at all. He'll do the takeoff. He'll generally speaking do the landing, although there is an auto landing system. Once the aeroplane is safely in the air, the autopilot will be engaged, at the autopilot will take you up to height. The flight management system will guide you through the airways and point you in the direction you need to go. And actually the pilot could completely go to sleep. The aeroplane would find its own way there, with very modern avionics and would even land itself.
Izzie - Hopefully they won’t be going to sleep!. If we fast forward to World War Two, how did cockpits change then?
Terry - They didn't really change very much. They had a few more instruments, blind flying instruments, so that pilots could find their way down and fly accurately in cloud. First World War; visual flying only, you need to see the ground. and if you couldn't see the ground you were in a great deal of trouble. So they had blind flying instruments, and the great aid was a radio because with the radio in the cockpit somebody on the ground could tell you where to go and radar had been invented. A chap called Robert Watson-Watt invented radar between 1915 and 1935, and that was able to guide fighter aircraft to hostile aircraft. And the next stage was having airborne interception radar installed in fighter aircraft, so when you get guided to within a mile or so of of the enemy your own radar can then guide you to it and you shoot it down.
Izzie - Now we're looking at the newest fighter jet, the F-35. How have modern day avionics progressed?
Terry - They are astonishingly accurate and amazing. For a start, the pilot is wearing a very high tech helmet, and his primary flight instruments, as well as the whole battle scene of a hostile aircraft, friendly aircraft, the assets around him are all projected on the inside of his visor of his helmet. He turns his head one way or the other, he gets a different view and the aircraft which are hostile, or not hostile, will appear on his visor where they are relative to him. The avionics are very complex and one of the big issues in the past of avionics in aircraft, is cooling. And if they weren't cooled sufficiently, they would be unreliable and they would fail. I remember flying in Lightning aircraft, the earlier English Electric Lightning aircraft, where the mean time between failure on the radar set was about 40 minutes which wasn't very good, and it was all to do with cooling and the thing heating up.
On modern combat aircraft, the avionics are absolutely reliable. They last forever, as they do on airliners and modern passenger jets. The other significant difference with modern air combat, is the support you’re provided by a number of other assets. There might be an airborne early warning aircraft which is maintaining the whole battle scene. You're being controlled by it, you’re communicating through it. You're able to find your own targets. Somebody on the ground might send you a message through a secure data link saying “here is the position of the target” you can identify it from your cockpit, you can then launch a particular missile, perhaps a laser guided bomb, or a missile against it and people in your headset will be watching exactly what you're doing, and the next step is almost asking permission, may I engage this particular target and a voice will say “yes you can” or “no you can’t.” conversely.
Izzie - Now there's obviously a lot of connection and communication there, and you said that there's this secure link that information is sent through. What if it isn’t, is there a risk that these F-35 fighters are too high-tech. Is there a risk of cyber attacks?
Terry - There is always a risk of cyber attack and the cyber attack will come in many different ways. It'll be attacking the ground stations, the radars, that are giving you vital information But it's measures and countermeasures. And if people are trying to undermine our capability, and cyber attack what we're doing, we're deploying measures to counter that. And there's a huge amount of research going on into into that whole area, most of which I hasten to add is very highly classified.