It stands for Aircraft On Ground. Usually due to extreme damage that requires repair in place. Boeing has an AOG crew that is second to none when it comes to repairing airplanes that are severely damaged in landing incidents or fires. They are packed and out of the plant in 24 hours to go to the site. Major assemblies sometimes are pulled out of the production line to be flown to the site. The best mechanics and engineers are chosen for the team and in the past they have done miracles in getting an airplane back in service. Years ago in one incident an Air France 707-320 under-shot the runway on the island of Guadeloupe ( sp ) and tore off the main landing gear and heavily damged the wings, engines, engine stuts, and lower fuselage. AOG crew repaired the airplane where it was and had it in the air in 30 days. Switches
It also means it is not legal to fly using it's M.E.L. (minimum equipment list) due to the fact that the airplane cannot be given a D.M.I. (deferred maintenance item). It does not mean it has severe damage all the time. For example a bad Air Data Computer or Inoperative INS that is required to fly RNP-5. both items can ground and airplane and render it AOG. My employer has a fleet of Lear jets for this very purpose. Paul
I've flown charters in Learjets to take mechanics and parts to fix AOG situations for airlines. Gulfstream has a G-100 (nee Astra) dedicated to assisting AOG customers.
I neverthought about MEL's and such. I have only had experience with the more dramatic causes of rendering an aircraft AOG but being short of an essential item other than a wing or landing gear is still cause for AOG. Perhaps I should have thought of the other possibilities but they ain't as interesting as a wheels up landing or an undershoot. The first AOG instance was a TWA 707 that landed inadvertantly when the new pilot tried to make a go-around after an over-shot landing. He was an ex-DC-6 pilot who reverted to prop procedures for a go-around: apply power, yank the gear up, decrease flap setting, and climb out. Instead of climbing out, the jet took time to spool up and accelerate while it was settling into the runway with the gear retracting. It screamed down the runway on its belly under full power for almost 5000 feet. The belly was ground down past the keel beam chord which is about 9 inches of solid metal. The engines were knocked off, the struts destroyed, and the lower wing skins damaged by fire. Large sections dropped off when the fire crew sprayed them. The belly was destroyed from the nose back to the middle of the 46 section. They put the airplane in a hanger and the AOG crew rebuilt it and had in the air in 30 days. They even replaced the lower wing skins which are really half inch thick planks of aluminum. My group and I had to identify and select the drawings that were needed to effect the repairs and to choose the correct assemblies and parts to ship. I wrote the airplane off when I saw the photos of the damage and I couldn't believe it when it flew one month later. There were many more incidents like this that were airborne in a month.
When I heard this term, it was nothing major like was listed above. AOG was being thrown around over on the Columbia forum for Columbia 400 planes that were down due to one or both of the starter battery's being dead. In order to shave a few pounds off weight Columbia uses custom made batterys. The custom battery's are rates at 6.5 amp's, or a total of 13amp's for the whole system. It would appear that these battery are a little to small, defective, or something, as there has been a high rate of failure. IE can't start the engine to go flying. The because it's a custom battery that only Columbia uses, and the high number of failures, there is no stock, they are back ordered for months. This leaves a bunch of nice new Columbia 400's stuck on the ground or AOG. Some owner have found a off the self replacement that fits, has a higher rating, cost much less, but is 10lbs heavier. But it appears you just can't swap out a battery in an aircraft, some one has to do a 337 or something to get the new battery approved. That's just nuts, it's a fricking battery, OK make sure your getting a aircraft battery, the correct voltage, and go. I would be pissed as hell if I had to say something like. Ha guy can I get a jump, the battery in my 600K airplane is bad, and I can't get a replacement.
For what it is worth? You do not need a battery to start an airplane. The aircraft's ignition system excitation current is supplied by self powered things called magnetos which are fired via the impulse coupler. One of the reasons you never turn a prop without being careful since it could fire if the P-lead is disconnected and there is fuel in the cylinders! When you turn a prop in the direction of normal rotation you will hear a clicking sound, that is the impulse coupler firing and delivering a shower of sparks to the ignition system independent of the battery. I always teach my students how to hand prop their airplanes for the dreaded master switch being left on and no help can be found. Obvioulsy there are some saftey considerations associated with this which I will not go into. Magnetos can operated independant of the aircraft electrical system for safety reasons. Having a dead battery in a Colombia 400 can be AOG but if you really wanted to depart the fix?, you could legally.
You are correct about the ability to hand-prop an airplane due to magnetos with impulse couplings. However.... Not all magnetos have impulse couplings! The Bendix "Shower of Sparks" magneto system (original equipment on my Comanche and lots of other aircraft) use a starting vibrator as opposed to impulse couplings to produce a high voltage spark with low engine rpm (ie while cranking with a starter). This system REQUIRES battery voltage to energize the starting vibrator. There is no way that you can turn the prop fast enough by starter or by hand to produce a spark without the vibrator. The vibrator is only activated when the magneto switch is turned to the "start" position (like that of a car) and once the engine is running, and the magneto switch is brought back to the "both" position, by spring return, the viabrator is out of the circuit. On the one hand this makes the airplane EXTREMELY SAFE for pulling the engine through during preflight. On the other hand, if you left the master switch on, you will need to charge the battery or use jumper cables to effect a start. Planeflyr
I Don't hand start my RC aircraft, and they are only turning a 10 -18 inch prop. Not even going to think about hand propping a real airplane.
Considering your level of experience that is a very good thought at this point in your flying. However, it is perfectly safe for people who are trained properly.
I highly doubt you could legally fly a Columbia with a dead battery. Could you do it, possibly, but legally? Good luck. Now, if you started it and the battery took a charge, then you wouldn't have a dead battery any more. But if the battery were defective and wouldn't take a charge (the scenario being discussed, I believe), then no. Have you ever hand-propped a big six cylinder engine? It's a bit different than hand-propping a 150 or a Cub. And all of this assumes that the Columbia uses mags, and not some sort of high-tech electronic ignition.
Does a Stearman, T210 or mooney count? The principal is the same. Assuming one can get the right amount of fuel into the cylinders. How about you, do you speak from experience? "Starting engines by hand, or "handpropping", has been a major aviation safety problem since the invention of powered aircraft. Until the 1950s a standardized procedure was routinely taught to pre solo students but since then few have received any instruction in this important subject at all. Now, with the proliferation of restored light aircraft and home builts without electrical systems that must, therefore, be started this way Larry has felt it is time to reintroduce instruction in this potentially hazardous procedure. Done properly following a detailed procedure handpropping is reasonably safe but it can be terribly unforgiving of carelessness and neglect." Quote from larry Bartlett who makes aviation videos. My initial instructor soloed in Jennies and ended his career in an MD-11. He taught me to hand prop when i was 14 years old. It is not a big deal with the right priming and safety precautions. That being said, I dont think i would care to do it again with my current level of fitness. the big six or radial that is. 150 and 172 is a snap. http://www.youtube.com/watch?v=3gAdkMIb_Fg http://www.eaa1000.av.org/safety/handprop/handprop.htm I am off to Europe. Happy Flying.
Yes, I have hand-propped airplanes. Like you said, a 150 or 172, not a big deal. A big engine can certainly be hand-propped, but it is more difficult and less safe. I haven't done it recently, though (and personally, I'm thankful for that!)
