Transport category ground handling..

skydiverdriver

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For those of you that fly transport category aircraft, I have a question. When I flew the FK-27, I had one pilot show me how to push the stick foreward on the ground during takeoff before rotation, and after all three wheels are on the ground upon landing. It worked very well, as it seems to make the aircraft stick to the ground very well.

Now, we all know that if you do this with a Cessna, or other light aircraft, you will probably start wheelbarrowing. Well, here is the problem. I do this in the CRJ that I currently fly, and I had one captain ask me about it. He said it felt like the rear of the aircraft was sitting up, and it felt unstable to him. I disagreed. He said that I shouldn't do that in a heavy crosswind, and I said that this was the time I would most likely do it. He said his experience in the Brazillia taught him not to do this, and I felt my Fokker time made it clear it was a good idea. I think the Fokker is closer to the CRJ than the Brazillia, but that's beside the point.

I flew with two other captains that had the same procedure as I, and one said he flew a 737 before and was taught this. The other captain said he studied this type of thing at Riddle, and he felt it works on a T tail aircraft.

I have also heard that 727 pilots are taught to do this, and it works well on other large types as well.

My theory is that the difference between a light aircraft and a transport category one is the percentage of the distance from the main gear to the CG, compared to the distance to the nosewheel. In other words, the main gear to the CG on my aircraft is say, 5% of the distance to the nose gear, where it's say 55% in a Cessna. So, since there is plenty of weight on the main gear, and may transport category aircraft could actually sit back on the tail if misloaded, this means more weight is needed on the nosegear.

I'm not an expert at this, but this is my theory. Please help me out here, if you know the answer, and I look foreward to your reply. Thanks for your help.
 

AWACoff

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Skydiver,
When I flew both the Brakillya and 328, I flew them both like a 172 as far as takeoffs and landings go. In a xwind situation, I would let the aircraft roll up onto the upwind gear and rotate (all of this of course at Vr). I have done it your way as well however and it seems to work just fine. I think it's more a personal technique.
Just my $.02 and tuna salad sandwich
 

bayoubandit

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Interesting, but i never liked using any more forward pressure that needed for nosewheel steering/control. Here's the reason why, on landing a concern was that after touchdown with full forward yoke, the tail would start to fly which would counteract the purpose of the spoilers of putting the weight on the wheels. Also, with the tail wanting to go up, it would decrease the amount of traction on the mainwheels which could result in slipping especially on a slippery runway. Not exactly what I would want on a contaminated runway with a crosswind and reverse thrust and this may be where your first Captain is coming from.

IMO, the faster you are going, the less forward pressure should be applied. I'm sure each airplane has its own characteristics and one technique is not applicable to all aircraft.

Does your flight standards or training dept. have any guidance on this?
 

Draginass

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In the KC135 (B-720) it was std procedure to go yoke forward after the nosewheel was on the ground, but not on the 757/767/747. I would suggest complying with the flight manual and not making stuff up. Leave that to the test pilots. That advice has served me well for a really long time.
 

surplus1

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Skydiverdriver

On this one, I think Draginass is right. If the FSM doesn't specify that procedure, then it's technique. Follow what the book says. If you have a serious doubt, check with Flight Standards, they'll be happy to set you straight.

By the way, I have flow both the F27 and F227 (typed). It's been quite a while but I don't remember any requirement for forward pressure either on TO or after landing. Sounds like it was a particular Captains technique and not necessarily the right one.

Dragin is right about the B720. Its a procedure.
 

skydiverdriver

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Yup, I agree, however, just because it's not in the book, doesn't mean it doesn't work well. Still, nobody is commening on my theory as to why it works. I also don't believe the thing about unweighting the rear wheels. Perhaps I should speak to a Bombardier test pilot, but I don't personally know any. I'm sure our mechanics could tell me how much weight sitting on the ground is on the nose and main gear. Just for arguement, lets say on a 30,000 lb empty aircraft, 25,000 lbs is on the mains, and 5,000 is on the nose. So, I push the stick foreward (not fully foreward, just some) and increase that to 8,000 lbs, there is still 22,000 on the mains. I don't think that's going to push you up in the air.

Yes, surplus, the F-27 technique was taught to me by a captain who had time in heavier aircraft. It may not be correct for that aircraft, but that may be just because they didn't see fit to make it a procedure. I don't know what would be involved in changing all of the flight manuals, but I'm guessing it wasn't enough of a benefit to include it. That doesn't mean it's not a good thing, or a safer way to handle it on the ground.

Anyway, thanks for the comments.
 

bayoubandit

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I agree with the other guys. Stick to the book, and if you think it's a good idea try bringing it up to your flt. standards for an addition or change in your procedures.

An MD-80 pilot was telling me about the tail flying on that airplane and unweighting the main wheels. I don't know what the procedure on that plane is. I'm no expert by any means, but it did make sense to me and that's why I threw it at you. We didn't have a procedure on the ERJ. Not sure about the 727.

BTW SDD, I was talking about full forward yoke.
 

corky

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swept wing transport jets are designed tail heavy. They have to be because fuel contributes to moving the cg forward and during takeoff when the airplane has the most fuel the CG is the furthest aft for any given flight. VMCG is defined when the aircraft deviates more than 30 feet from the center line at max thrust on the operating engine, most aft CG with no or minimal nose wheel friction resistance(ie..icy runway). This was accomplished on the MD-11 and MD-90 cert test by disconnecting the nose wheel steering hydraulics and leaving the nose wheel to caster and the test was actually flown with the nose wheel off the ground for the 717. So obviously applying a little stick forward pressure greatly increases your controllability due nose wheel tire side force due to friction up to and beyond Vmcg. In my 717 training I was actually taught to hold the stick forward 3 seconds after VR on a V1 cut...if you have the runway. I was taught this by Boeing cert pilots and though this isn't in the AFM it is taught as a technique.
AFMs and FCOMs are developed to satisfy FAA cert requirements only after a 1000 hours or so of flight testing on test birds based on engineering data and test pilot input, not full production birds filled with people. Techniques are developed to finess the flight after thousands of hours by line pilots. Thats why we will always have little pink pages in our manuals. They're generated from input and write ups from line pilots.
Not every technique will be in the mannual. I was in a JAL MD-11 accident investigation where they ran off the side of a wet runway due to the right t/r failing to deploy. The pilot couldn't control it and when we asked why he didn't apply differential braking, he said it didn't say to do so in the manual.
 
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skydiverdriver

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Thank you Corky. Finally, someone who sees where I'm coming from. Some of your manual was written by lawyers, as well as the regs, and they don't cover everything. I once had a captain who would actually take his hands off the yoke after touchdown! I scared me a bit, and I had to speak to him about it. In the F-27, we used to let the non-flying pilot take the tops (yoke) after touchdown, so that the flying pilot could take care of the power levers (for ground fine pitch), brakes, and nosewheel steering if needed. Not all airlines do this, but some pilots I've flown with do. Just because it's not in the book, doesn't mean it isn't a good idea.
 

corky

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I'll add one caveat to that skydriverdriver,

Whatever we as pilots do that's not in the book, we will be on our own defending ourselves if it comes to being on trial in an accident/incident investigation and our technique is involved. The pilots always blame the airplane and the manufacture always finds a way to blame the pilot. Use good judgement in applying any technique.
 

avbug

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Use appropriate techniques for the particular airplane. To make any assertion that any particular technique is appropriate because it's a "large airplane" technique is absurd. Some large airplanes are landed and flared, and the column held aft. Others are pinned on.

Do NOT ignore the manufacturers recommendations based on the concept that something isn't in the book. Bad idea. The JAL pilot failed to use common sense; this is different than ignoring manufacturer recommendations.

Don't buy into the idea that adding forward pressure "lifts" the mains, or reduces the traction on the mains. In most transport category aircraft, putting the yoke forward reduces angle of attack on the wing, the main lifting surface. This reduces lift, placing more weight on the mains. The mains then act as a fulcrum, and forward pressure on the yoke applies a downward pitching moment applying force on the nosewheel. Weight isn't taken off the mains; it's applied aginst the nosewheel.

The "lifting" force of the horizontal stab applicable when down elevator is applied is reltiavely insignificant in nosewheel airplanes, with respect to "lightening" the load on the main gear. Don't think twice about it.

Some might be tempted to compare down elevator on a nosewheel airplane to that on a conventional gear airplane such as a DC-3, but there is NO comparison; apples and guava fruit. Not even close.

On some aircraft, adding forward pressure after landing will unnecessarily load the nose gear assembly. This may be especially true on free castering gear. It may also impinge on control mechanisms.

Putting the control yoke forward on a light nosewheel airplane doesn't necessarily cause "wheelbarowing", but it can lead to an early demise of the oleo strut and the Lord shimmy damper, as applicable. Go with the design and intent of the airplane. Use input from other pilots, but don't base what you do with an airplane on what other pilots think is a great idea; I've seen many cases where an entire pilot community did something relatively stupid with an airplane because mythology taught them to do so. The "pink" pages aren't always right, either.

Each airplane is flown individually. Don't apply what you know from one airplane and assume it appies to another, because it may very well not.
 

skydiverdriver

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Corky,
yeah, I know, if it's not in the book, I'm on my own. I'm sure they could get us in trouble for doing something that IS in the book as well. BTW, I also remember a 727 captain I flew with once that held the yoke foreward in a Seminole. I had no idea what he was doing, but it sure felt stable on the ground when he did that. He also flew it like a large aircraft, and it was nice. Thanks for the input.
 
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