Modelman,
You were taught correctly. What keeping your hand on the throttle really does for you is not only keeps the throttle forward, but gives you immediate tactile or feel feedback if you have a problem. If the engine does fail on you, you know it's not because the throttle backed off...it's in your hand. You're "in the loop" with what's going on with the airplane.
In multi engine airplanes, other factors come into play. One of the things chuck referred to was directional control. If one engine quits, you lose not only power, but you have some powerful forces trying to turn the airplane. If it gets too slow while still on the ground, the ability to keep the airplane going straight is lost, and as a result, control is lost. In flight, if there's not enough rudder authority available to fight that turning, the airplane can roll over and control will be lost. Multi engine pilots learn from very early in their training that in some cases the only choice may be to pull back or reduce power on the good engine(s) when one fails. that's one consideration.
Another consideration, especially as airplanes get heavier and heavier, is both the amount of runway required to take off, and what to do with the airplane if that takeoff needs to be stopped. Unlike a single engine Cessna, for example, one may be nearly out of runway by the time one rejects the takeoff, and one may need a lot to get stopped. Certain additional calculations are needed, then, when planning a takeoff in a larger multi engine airplane. One doesn't just need to know one's takeoff roll, but other numbers too, such as the accelerate-stop distance, balanced field length, etc. Other numbers such as the engine-out climb gradient are very important, as are the minimum speeds with a failed engine at a given weight, for directional control.
As weight increases, the ability of the brakes to stop the airplane decreases. Brake energy, the ability of the brakes to absort heat before they fail, is an important issue. Many larger airplanes have brake energy charts, but the fact is that if you have to reject a takeoff, you can have brake fires, directional control issues, a host of different potential problems...including tires that explode or burst because of skidding, temperature, etc. Having tires burst or go flat on a rejected takeoff in a large airplane isn't uncommon, nor are brake fires.
In older large airplanes such as what chuck is describing, a lot of this data just isn't available. I also flew WWII era bombers doing firefighting, and while it would be nice to have data like accelerate-stop and climb gradient information, it wasn't available. Add to that the fact that one is often departing from less than ideal runways...many tanker bases used to be located at airports with only a few thousand feet of runway, and often we used every foot of it before the wheels left the ground...the decision to reject a takeoff is a critical one.
Certain speeds come into play. In large airplanes, one of those speeds, generally the first one reached, is refusal, or decision speed. This is commonly just called V1. As a very generic rule, anything that occurs prior to V1, you can reject the takeoff, anything after you can't...you MUST go fly. However, due to the high risk involved in a high-speed rejected takeoff, nearly universally the wisdom is broken down a little more fully. One can reject for anything at a lower speed, but at a higher speed one may reject only for very critical items such as engine fire, engine failure, or loss of directional control.
The speed usually chosen for that line is about 80 knots. When a takeoff is briefed in most large airplanes these days, ranging from business jets to airliners to air tankers, usually it's briefed as any problems that present a safety of flight issue upto 80 knots, we will reject. After 80 knots, we will reject only for the previously mentioned engine fire, failure, or loss of directional control. It's just too dangerous to reject the takeoff otherwise.
To give you an idea of how dangerous it is, the FAA used to require a high speed rejected takeoff as part of the demonstration a pilot must show when taking the checkride for his multi engine rating. However, due to the number of training accidents and fatalities, even in light twins, the FAA doesn't authorize their examiners or inspectors to allow it above 40 knots, now. Keep it slow, because even in a light twin, a high speed rejected takeoff can be very dangerous. Statistically it's one of the most dangerous things you can do in a multi engine airplane (especially a large airplane)...high speed, low control, close to or on the ground, high potential for loss of directional control, max brake energy and temperatures, your stopping distance largely behind you, obstacles ahead...you're better off taking it flying and bringing it back around under control to land.
In a single engine airplane, you don't have any choice; if the engine fails then you're coming down. You're often taught to land straight ahead or keep the airplane going straight ahead and accept what's there (or make slight turns to avoid obstacles, if you can). In a large airplane, there are other options and other considerations. Chuck's point that simply pulling one engine back in a reaction to the problem would have been a very bad choice, is a valid one. He uses that as an example to show that he didn't just pull one engine back as a knee jerk reaction; he considered the effects and shut down both engines. He did so with the added benifit that the engines were stopped, further reducing their hazard.
The reason I responded as I did, and do so again, is that while clearly he made a successful stop, rejecting a takeoff for two functioning engines at takeoff power is a bad choice. Why reject the takeoff when things are functioning as they should? You don't.
This is particularly true in an air tanker. I've spent a number of years flying air tankers doing firefighting in older WWII airplanes, turbine equipment such as the C-130, and even in single engine air tankers such as the 800 gallon Air Tractor AT-802F. When carrying retardant more than any other load (foam, water, etc), punching off the load during a rejected takeoff can do several bad things for you...one is that it can coat your brakes. It's very slick, reducing brake effectiveness. It's one of the things we teach not to do in the fire schools every year. It also coats the ground and can make directional controlan and braking difficult by reducing the coefficient of friction with the surface. If this occurs during an overrun onto grass, it's like operating on oil or ice. Very slick, possibly even no braking. Moreover, braking effectiveness is a function of speed, the brakes, and the weight on the wheels. Effectiveness is reduced when the weight is lost.
Older airplanes used what are called expander tube brakes. Unlike what's on your car or Cessna, these used a rubber-impregnated canvas bladder full of hydraulic fluid to expand and compress the brake assembly. These are susceptible to catching fire and with heat, the canvas and rubber breaks down and can fail. I've seen them burning and smoking on several occasions as a result of too much use on landing or a rejected takeoff. They lose efficiency much faster than most modern large airplanes, and have their own limitations. Once they warm up, they're done...unlike carbon fibre brakes found in say, a typical airliner today...which get more efficient the hotter they get.
In a tanker, during a takeoff emergency about the only time you'll be jettisoning the load is if you intend to take it airborne and need to get rid of the weight to do it. We strongly counsel pilots every year not to lose the load if they intend to remain on the ground and stop, especially if it's retardant. It's always a judgement call, and chuck made his judgement call. However, if you were to post that scenario in the tech forum and have it evaluated by professional pilots who understand the real significance of rejecting a takeoff with two functioning engines...you're going to get nearly universally the same response as I've provided here. Yes, he made it, yes, he made a good decision to kill both engines instead of just one...but he shouldn't have done it in the first place. With two good engines, rejecting the takeoff with two good operating engines and the runway behind, is the wrong choice...and he ended up off the runway as a result. It could have been much worse. Runway overruns and high speed rejected takeoffs, especially for fully functioning engines...are ill advised and have resulted in a lot of tragedy over the years. Lucky doesn't make it right.
Chuck's example so far as not moving a control before you think about it, is valid. His example of what occured, is not...and put that scenario before the many professionals who frequent the board and you'll get the same response. That it's not recognized in the private pilot forum is to be expected; it's not part of your training, and you're not expected to know that. Chuck knows that, too.
I fully agree that fast hands kill. I've seen pilots shut down the wrong engine. I've seen pilots panic and do things they really ought not. This may be such an occasion. Directional control wasn't lost, but the takeoff really shouldn't have been rejected, either...statistically speaking, and speaking in terms of proper training and procedure. My grip is the decision to post it in the private pilot forum and hide a good decision in a bad one, specifically chosen before a group that probably wouldn't recognize the fact...and then to defend that bad decision.
Chuck is right regarding acting too quickly. I've always taught that the first thing you should do in nearly all emergency situations is sit on your hands and count to ten. Not always literally, of course, but there are very few things that happen in an airplane which demand you act NOW...and whereas pilot error is the cause of the majority of mishaps, getting the pilot to slow down a little before he does something stupid (like reject a takeoff for two fully functioning engines) is a very wise thing to do.