flying heavies

[av8raaron]

Just a question on other folks' experience in larger jet - all my time so far (less than 100 hours) has been in Cessna single-engine stuff. I got a chance to fly a KC-135R simulator today (full motion, FlightSafety type of stuff - way cool) and was having all sorts of problems holding centerline on final - lots of problems overcorrecting. Just wondering how other people have flown getting into a heavy aircraft for the first time. Any info or experiences would be appreciated.

Thanks,

-A

 

[flx757]

I'd be willing to wager that your "problems" weren't in flying a "heavy" for the first time...it was flying a simulator for the first time. A simulator is a simulator...an airplane is an airplane. There are different tricks and techniques employed in flying each one successfully...and they aren't necessarily the same.

Over-correcting is probably the single biggest problem I have consistently seen in my many years of sim instructing. Simulators are computers. You put certain numbers in (i.e. pitch attitudes and power settings) to get certain numbers out (i.e. airspeeds, vertical speeds, etc.). You must put your numbers in and give the computers time to react before changing what you just put in. Make a SMALL correction, if you need one. Wait.............see what it gives you. If you need more, make another SMALL correction. Wait........................see what it gives you.

Most simulators are far more sensitive to control inputs than the aircraft. The aircraft is inherently stable, therefore it requires a certain amount of control input to change what it's doing. The simulator, on the other hand, will react to whatever inputs you make. And almost without exception, simulators are very pitch sensitive. Meaning it requires very little control input to get a very large pitch change. Drastically different than you would get in the actual aircraft.

So don't worry so much about your perceived performace flying the KC135 sim. It just takes practice to learn the nuances of flying a simulator. I'll bet if you got the fly the actual aircraft, it would seem suprisingly easy compared to your sim experience.

 

[surplus1]

Just a question on other folks' experience in larger jet - all my time so far (less than 100 hours) has been in Cessna single-engine stuff. I got a chance to fly a KC-135R simulator today (full motion, FlightSafety type of stuff - way cool) and was having all sorts of problems holding centerline on final - lots of problems overcorrecting. Just wondering how other people have flown getting into a heavy aircraft for the first time. Any info or experiences would be appreciated.

Thanks,

-A

Your "problem" is not at all unusual. Assuming the sim was functioning properly (often they aren't) these are some thoughts (not answers). Even the best simulators, don't really fly like airplanes. Control loading is one of the most difficult things to "get right" in a simulator's program. That could be the sole cause of your difficulty.

In faster/heavier aircraft "trends" are more critical than in slower aircraft. You must see the need for a correction coming, before you're actually there. (Don't know if I can write what I'm thinking). If you're drifting, you must notice the tendency to drift earlier so that corrections are made sooner and are therefore smaller. A small correction, followed by a wait and see what I got is good technique, especially in a simulator.

Momentum is another factor. When you displace a light object and seek to "put it back in place" the effort required is minimal. This relates to a basic law of physics - a body in motion tends to stay in motion. When a heavy airplane is displaced from the desired track, you're moving several hundred thousand pounds in a direction at a speed. Control input has to stop the momentum + correct the deviation. If input is delayed (because you didn't notice the displacement soon enough) the correction (input) required is relatively larger. This then starts the momentum in the opposite direction, requiring removal of the input before your get to the actual desired position or you'll "drift" through it and deviate to the opposite side of the desired track. When you recognize that new deviation, you make another input to get back and repeat the first problem.The result is sort of like "S" turns back and forth across the desired track.

The controls work the same way that they do in your 172. They may be more or less sensitive and require more or less movement (displacement) to achieve the desired result, but the differences in speed and weight produce moments that are much greater in force that those of the light aircraft, if not anticipated, they will almost always result in over controlling, S turns, wing wobble or can even induce dutch roll if carried to the extreme.

You must see the problem coming sooner and make smaller corrections before you have a large displacement from the desired course. The bigger the displacement, the bigger the correction, the greater the tendency to over control. Timing of what you do is a big part of it.

I don't know if any of that makes sense to you. Its just an effort at explaining a concept of what's happening that might give you some ideas on how to avoid it. Don't view it as a "flying lesson".

As your experience grows in the light airplane it will transfer to the larger airplane with less difficulty. It's similar to learning when to begin your turn from base to final, how much bank to use, and when to begin the roll-out, so that you wind up on final, aligned with the centerline and with the wind correction built in. The problem is no different in the "heavy" and the solution is no different. What changes is the timing and the control inputs required. Practice will get rid of the bugs.

In my opinion the 707 is like a truck, while your 172 is more like a sports car. Different aircraft respond in different ways. Some are "heavy" on the ailerons and very sensitive in pitch. Others are the opposite. All take a little getting used to.

 

[flx757]

Excellent point that Surplus 1 made about recognizing the trends early, therefore lessening the amount of correction necessary. The less correction necessary, the less the tendency to over-control. Again, once you determine that some input is needed, give your inputs a chance to work before adding more.

Also, Surplus gave a good discussion on momentum and inertia. Another good reason to anticipate what inputs may be needed, so that you can keep your inputs small. And also, another reason to give your inputs a chance to work before adding additional corrections.

 

[bobbysamd]

Sim v. airplane

I flew the 727 sim once at the Mike Monroney Center in Oklahoma City. I had never "flown" a sim before. I did terribly!! I did because I was trying to "fly" it like an airplane. I also remember "flying" a turboprop sim in the same place. I did a little better with it.

I then "flew" the AST-300s at Riddle. Same story, but one of the deals at Riddle was that instructors got unlimited sim usage. So, I spent plenty of Saturdays, Sundays and downtime flying those sims. I discovered the same thing flying FSI's Frascas.

The long and short of it is you have to learn how to "fly" a sim. The control inputs don't feel the same and, even if you dial in smooth air, sims are all unstable. That is a benefit, because it hones your instrument scan.

Sims are terrific for teaching procedures and building your cross-check, but be careful not to get hooked on them too much because they don't react the same as airplanes.

 

[ShawnC]

I know that on several sims that I have used I would control the sim using the rod connecting to the yoke. Why, because they way I wouldn't over correct. Thats just something I noticed with sims.

Now for jets, you would have to take to one of the jet pilots, but from reading this board jets sound like they have to be flown very precisely compared to the little bug smashers.

 

[bobbysamd]

Jets v. "bug smashers"

Very astute observation. You really must fly jets more precisely than light aircraft. You have to establish very precise pitch, power and trim settings; otherwise, the airplane won't do at all what you want it to. In light aircraft, you don't need the same precision, although you should fly them precisely. That is one reason why the AI on jets is much bigger in comparison to the other instruments in the six-pack.

For example, many years ago Richard Collins wrote an article in some pilot mag about flying the Concorde. Actually, he "flew" the Concorde sim. He talked about establishing a very precise pitch angle of something like 14.6 degrees up for rotation. It may sound ridiculous, but Collins wrote that his British Airways instructors insisted the sim flew exactly like the airplane.

At FlightSafety we were training Alitalia students in our Cadets (Warriors) and Seminoles. Alitalia demanded, properly so, that we teach our guys the hub-and-spoke control-performance method of instrument cross-check, emphasizing precise pitch control and emphasis on holding pitch precisely by reference to the AI. And, it works, rather well! I would cover up all instruments except for the AI and the power instrument during BAI training in the airplane. I would have the trainee establish and stabilize a pitch and power setting. Then, I would uncover the instruments. It was truly amazing that airspeed would be within a couple of knots or so of target. Even using a somewhat imprecise GA AI, worn gyro bearings and all. Rate climbs and decents would be either right on or within 100 fpm.

I'd strongly recommend that all interviewees get some sim in before the interview, but practice "flying" the machine almost exclusively with the AI. Many interview prep coaches recommend that procedure, because it almost guarantees you will fly the heavy jet sim at the interview within standards and with stability.

 

[bigD]

Flying heavies

Sometimes I get some real big people wanting to fly with me. Although I try and accomodate them, it can be a real pain to trim the plane when their love handles are covering the center console. Heaven forbid I lose an engine - there's no way in hell I'd be able to get to the fuel selectors and crossfeed the good one.

My tip when flying with only one heavy in the copilot seat is to place an anvil or three in the baggage compartment - otherwise you'll run out of elevator in the flare and risk damaging the nosegear.

 

[trigeek]

Excellent points indeed. One other thing to remember is different aircraft are more or less responsive and it has little to do with actual size. The 767 and 757 handle MUCH better than a MD-88 or 90 because on the different flight control design. The C-5 doesn't fly nearly as heavy as one might think. I personally think it is more responsive than the C-130.

Just my 2 cents

 

[Austpilot]

Excellent post surplus 1, that pretty much sums up flying a heavy to a tee.

One thing to remember, like everything else,is that the handling skills required to fly a heavy come with practice, and sims no matter how good they are are never the same. I know a 737 pilot that makes it a point to regularly hand fly the jet to transition and then down from transition, everybody scoffs at this guy, but you should see how he flies the sim on raw data!! the best!!

Anyway, my two cents is that it's not so much to do with manual flying skills, it's all about systems and energy management and surplus 1's post described the energy management point very well.

Oh and KEEP YOUR FEET OFF THE RUDDER PEDALS!!

 

[TurboS7]

Sim is a pain in the butt, but the airplanes fly wonderful. I have 300 hours of sim time and I look at that like I am a brand new pilot. The older sims are a nightmare the newer ones are a little better. Generally a person that has trouble in the sim does great out on the line and vs. versa.

 

[flx757]

That's a pretty broad statement there, Turbo. I've known plenty of pilots that do a good job BOTH in the sim and on the line. Most pilots I know do a good job on the line. The ones that don't are few and far between. The ones that do a good job in the sim are the ones that want to do a good job in the sim. You will always have those with the attitude that they want to do just good enough to get by, and it shows. I like to set the standards a bit higher than that for myself, and I know there are plenty more pilots that do the same.

 

[TurboS7]

You are obviously one of those exceptional astronaut types.LOL We call checkairman astronauts, though when a line guys tries he can fly circles around them.(Don't take it personal I am just letting you in on some MAI humor.) I agree with you about the trying part in the sim, it just takes practice. You(as a checkairman) see the sim all the time a line guys sees it twice a year. Ask Bobby Bonds if he could hit a home run if he saw pitches just twice a year-no way. Considering the big picture it is amazing that any of us pass.

 

[DC10]

Heavies

Weight has everything to do with controllability on heavy jets. On the DC10, our max take off weight is 572,000 lbs. At that weight the aircraft is extremely slow to respond to pilot inputs and you have to think well ahead of the game. If you make a correction and wait to see the result before re-correcting, you're already behind. The key is in anticipating what the aircraft will do and planning well in advance.

On the other hand we sometimes fly really short repositioning sectors at very light weights. I think the lightest I have taken off in the DC10 is around 300,000 lbs which as you can see is about 130 tons below MTOW. At that weight the plane handles like a fighter jet. It will max out the VSI on climb (6000fpm+) and is very sensitive on the controls.

Also, light weight landings are much more difficult than having the stability of a heavier aircraft.

Hope this helps.

 

[skydiverdriver]

Well, I don't fly a heavy, but the thing I noticed the most, coming from a light aircraft to the F-27 and jet, is that the cg is 30 feet behind you. When you are on final with a crosswind, you are out in front of the cg, instead of near it like you are in a smaller aircraft. It seems strange at first, especially when you kick in the rudder to land streight, and the whole cockpit moves across the runway. Also, the thing about planning ahead is true, especially with speed control. You also usually fly down the glideslope with some power on, as idle will take you below your ref speed.

I personally think that the computer simulators are a good start to learn how to fly something larger. I got my first laptop on a trip once, and had a very experienced cargo pilot fly it once. I couldn't get the thing to do anything, but on his first time he landed it like he had designed the thing. I was pretty humbled. Good luck.