Steering on Takeoff
 

Hey Guys/Gals,
Somehow, my suite mate and myself got into talking about takeoffs in transport category jets. He insists that the tiller is used for the first 80 kts on the takeoff roll because there is no rudder steering tied into the nose gear and it's not effective until 80 kts and that's the whole point of the 80 kts callout. Just curious if this is true because it doesn't sound very logical.

That's how it works. On the ATR we do a 70 knot callout for that reason, but I guess on most larger jets it's 80 knots.

The tiller is not normally used once lined up on the runway but it could be low speed. The rudders still move the nosewheel regardless of airspeed. The 80 knot call has nothing to do with tiller use. It's to distinguish the high and low speed abort regime.

He is partially right. Some jets have nosewheel steering tied to both tiller and rudder pedals. Rudders are the first flight controls to become effective during takeoff roll. 80 kts is about the time where rudder deflection is more effective in maintaining runway centerline than nosewheel steering. Tillers are also more dangerous to use at high speeds.

It also serves as a way to x-check ASI with other side

727 sim I was in during college had an 80kt call-out, and but it was, as mentioned above, is a cross-check speed. The rudders do tie into the nose-wheel steering, but it is limited in comparison to what the tiller does(not sure angle in degree's).

My only experience with a nose wheel tiller was on the P-3 Orion, you would have your hand on it at the beginning of the T/O roll until rudder authority was gained, 40-50 kts or so IIRC. On the landing rollout, I think we had a standard of 65 kts or less before you were "allowed" to put your hand back on it. You could pop a nose tire very easy with the tiller.

On the Q400 the pedals have up to 8 degrees of nosewheel stearing so the tiller is not used during takeoff or landing until it is time to make the turnoff or in the case of a high speed you can hold off on the tiller until stopped. But its the CAs plane so he is in the tiller when he feels like it and takes the controls from me.

From what I understand the 80knots reason is for crosschecking the instruments as well as pilot incapacitation...if you say 80kts and they say nothing maybe the bloke is dead and you should consider the brakes.

True as well. There are several good points stated above. My main point was that I've never heard it used as a cutoff for the tiller and don't think it was a valid statement.

I see your point..I did not really notice that, but im with you on that one and do not think that the callout is for coming off the tiller.

Hey guys, thanks for all the responses.

In the C-17 we can use tiller or rudder pedals to steer irregardless of speed. We use the 80kt call to ensure power is set as our autothrottles (if used) will clamp onto whatever power is set at 80 knots. Also, we use it as a high-speed vice low-speed reject threshold.

In the ERJ, once we are lined up on the runway, the tiller is no longer used.

The CRJ has +/- 8 degrees of sterring with the pedals so there is no need to use the tiller on takeoff roll or landing.

Thanks again guys! I didn't think it was very logical nor in the best interest of safety to not have your hands on the control column on the takeoff roll. Also, I figured it would be pretty difficult to make adjustments with the tiller while getting close to 80. Even if there was say the FO on the controls while the Capt. steered with the tiller, it seems there'd be a redundancy in transfer of controls and the pilots would be doing too much.

What all the other guys are saying is correct. Mostly used as a high speed/low speed regime separation. Most Autothrottles need the thrust set by that point as well.

We are prohibited from touching the tiller above 40 knots per company procedures.

In my experience, you never move the tiller much, by the time you get speed on the tape you have rudder authority. Transfer of controlls is moving you hand from your knee to the yoke, not that big of a deal.

707
 

The 707 and 720 did not have a link between the rudder pedals and the nosewheel steering. On those first generation jet airliners the captain did use the tiller to steer until reaching 80 knots, at which time the rudder would be effective. Beginning with the 727, and all subsequent Boeing models, there was a link to the nosewheel steering through the rudder pedals. The tiller was no longer held, but the 80 knot callout remained, for all of those reasons mentioned in previous posts.

Depending on the acft and operator, 80 knots is more of a general call out. Rudder effectiveness is directly related to Vmcg (min control ground speed). Some aircraft's nosewheel steering are directly connected to the rudder and some are not. Each acft manufacturer will define what criteria they used to define Vmcg. (ie with or w/o nosewheel steering). Generally speaking, most acft will be above Vmcg when 80 kts is achieved. Therefore it is safe to take your hands off the tiller.

With crosswinds, the nosewheel will be used until the acft reaches a speed in which the flight controls are able to maintain runway centerline.

That's not how it works on either the 737 or the DC-9/MD-80. The rudder pedals give you some limited nosewheel steering authority.

Not true. On a 747 its between 114 and 132kts depending on T.O. power setting. Granted, that considers a critical engine failure which would be farthest from centerline, but I would suspect that on those hi-powered, big twins, Vmcg could be a pretty high number. You would have to talk to a 757/767/777 driver to confirm that for you.

Ailerons dont come into play for Vmcg. Anything more than 2 degrees (on a Boeing) effectively nullifies your T.O. data.

Like I said, "Generally speaking". I also said that depending on the aircraft. My post was meant to be a general post...not a thats not how the 73/75/74 works. Of course a 747 will have a higher speed. The more non-certerline thrust that is generated the higher the speed. I agree. But to quote the 72 Flight Ops Manual, "Eighty knots is the defined point that separates the Low Speed Regime from the High Speed Regime. In the Low Speed regime a takeoff may be rejected for a number of malfunctions. In the High Speed Regime the number of malfunctions that require a reject are dramatically reduced. The Captain must remain "go oriented" in the High Speed regime."

With that said, in a high speed regime it is safer to continue the takeoff than it reject. Below 80 kts (accelerate-stop oriented) it is safer to keep your hands on the tiller for reject purposes.

The bottom line is that above 80 kts you have increased control and reduced runway length/safety margin. Therefore, it is safer to take your hands off the tiller above 80kts than it is to take your hands off below 80kts. It is also safe to assume that if you are using a 80kts call, 80 kts is probably closing on Vmcg. On the C-130J, we use 70kts as the speed to define high speed regime. So for certain malfunctions you would reject prior to 80kts and for others you would not. For malfunctions that are considered critical to safe flight, you would reject in the high speed regime (80kts - V1) b/c it is considered safer to accept the high speed reject on reduced runway margins than it would be to take it airborne.

The original question asked, "He insists that the tiller is used for the first 80 kts on the takeoff roll because there is no rudder steering tied into the nose gear and it's not effective until 80 kts and that's the whole point of the 80 kts callout."

My original attempt to answer the post was probably to vague and general. Each aircraft is going to be different, but the standard operation procedures regarding take-off/reject decisions will be similar.

BTW, does the 73/74/74/76 use a 80kt call out?

The Capt guards the tiller until the 80kt call at our airline in the 747 - if you lose the critical engine you'll need the tiller to keep it on the concrete up to around that point. It's also a check for power set/throttle hold as previously mentioned.

The flying pilot has the rudder, the FO will hold nose down on the yoke if the Capt's flying. If it's the Capt's leg they'll move their hand from the tiller to yoke at 80 kts.

HTH
Spongebob.

In the Hawker there is absolutely no nosewheel steering in the rudder pedals. The pilot flying keeps one hand on the tiller and the other on the throttles until 80 kts. The non flying pilot holds the controls with crosswind correction up to that point. It takes some getting used to, and requires good crew coordination.

Tiller? I wish I still had one of those... 100% steering through the rudder pedals in the Slowtation.

HAHAHA......priceless

In the airplanes I flew (KC-135, 727, 737, 757, 767, MD-80, Airbus among them) NONE recommended that you use the tiller for control on the runway. Authority on the rudder pedals was 8deg either side (for some reason I remembered it as 12deg) and with the tiller it was 78deg. You can scrub a set of tires very quickly using the tiller and it MAY not be very effective in controlling the direction of the aircraft as proved by the 737 crash at LGA back in the 90s. As for the yoke, it is recommended that you keep slight forward pressure on it to ensure good nosewheel contact as speed increases on takeoff.

The 80kt call is many things... as noted, an airspeed check, the point at which one changes from low speed abort criteria (just about anything including caution lights) to high speed abort (fire, eng failure, perception the airplane will not fly) and this will include verification that the engines are fine, autothrottles/autothrust (if available) is operating correctly. Busy time...

It may vary with aircraft but I have never been in a community or on an airplane where the tiller was used as anything other than for taxiing where small radius turns were required.

+1.

And if I may add, the Tower 747 accident at JFK.

Hands Off of the Tiller
 

:)ERAUdude:

Once the aircraft is lined up with the runway centerline, steering is done with the rudder pedals. It may vary a degree or two with different aircraft types but on most Boeing transport category aircraft, there is 7 degrees of nosewheel steering either side of centerline with the rudder pedals. That's more than enough to keep the aircraft on the centerline.

In initial sim training, we teach do NOT use the tiller to steer the aircraft on the runway. Period !! Don't even touch the tiller. Period !The same holds on landing, where it is even more critical.

I'm aware of a transition pilot who used to grab the tiller on a rejected take-off. After about the third time (being told not to touch the tiller on the runway), the instructor rapped his hands and knucles so hard, he had welts on them. Didn't make it through training but I've been told drives a nice bread truck now.

The "80 knot" call has many purposes. It's a cross-check of the airspeed indications, a validation that the autothrottles have entered the " hold mode", entering the "high speed abort" criteria, and depending on the aircraft, numerous system functions begin at 80 knots.

Hope this helps.

G'Day Mates:)

Whoa phantom flyer...4 month old thread.

really simple answer...first officer doesn't have a tiller, and yet he takes off. two people dont have control of the plane at once...hence the positive exchange of flight controls. so no, you do not need the tiller for t/o, and 80 knot calls have nothing to do with it.

nose wheel steering
 

The A300/A310 rudder pedal steering is limited to 6 degrees
The tiller can control nose wheel steering to 65 degrees either side and is not normally used on takeoff. When disconnected (a maintenance/ground crew function) the nosewheel may be deflected 95 degrees under tow.

I only use the tiller in cruise flight at speeds of .76 or greater.

After reading all the other posts in here, I thought this was some kind of a contest to see how stupid of a comment you could make about the tiller.

It is the internet, boundless opinions and little useful info!:cool:

Personally I only use the tiller when I'm in the 727 sim, because that's the only time I've touched one(and that's been 4+yrs ago). Ah to fly planes that don't have one, such simplicity!

Sometimes They Do !
 

Well, sometimes the First Officer does have a tiller. On the B-747-400 and some Triple 7's, there is a tiller for both seats. It doesn't change the policy of "no hands on the tiller during take-off", but it's there. ;)

G'Day Mates

not sure if this was ever defined in this topic, if it was I'm sorry.
What's a tiller?

nosewheel steering for taxi purposes... http://www.737ng.co.uk/tiller11_170608.jpg

and on the airbus... the "U" shaped device just to the right of the sidestick flight control here: http://en.wikipedia.org/wiki/Image:F...21_cockpit.jpg

aha, thank you ! :)

Good answer! I teach the SAME items on the Douglas MD-11, and it isn't "technique."