correct as-is NWS engaged at touchdown

[Reusenfisch]

Pilots!

I noted that the nose wheel steering is activated at touchdown. I think this is not correct, but correct me if I am wrong. 
 

Greetings

[razo+r]

43 minutes ago, Reusenfisch said:

Pilots!

I noted that the nose wheel steering is activated at touchdown. I think this is not correct, but correct me if I am wrong. 
 

Greetings

Do you have any source that says it is not accurate?

[Reusenfisch]

Hi, actually not. But as a retired  Militarypilot I find it very dangerous. All aircraft I flew had never the NWS engaged at touchdown. 

[Muchocracker]

It's designed to be engaged during takeoff and landings. Explicitly mentioned as such in the NATOPS checklists. The steering gains get reduced with speed to prevent oversteering.

Edited April 15 by Muchocracker

[Reusenfisch]

Hallo,

At touchdown in the Hornet the nose wheel steering is engaged. I couldn’t find anything in the docs. But as a retired military pilot I doubt that it is correct. It imposes a dangerous situation regarding directional control. Image landing with high cross winds compensating with rudder inputs. Just a split seconds later the nosewheel touches the runway and the deflection kicks in. That can’t be correct. 
Unfortunately I can’t attach a track since I am on vacation  

Greetings

[Draken35]

The same manual mentioned above explicitly mentions that it is automatically engaged during landing in low mode with weight on the nose wheel. 

[Bob1943]

Former military pilot here as well (T-37, T-38, F-111, AT-33, F-100, A-37).  Completely agree with Reusenfisch regarding the danger of auto nosewheel steering engagement upon touchdown.  In all the aircraft that I flew, nosewheel steering was manually engaged at the pilot's discretion upon the landing rollout.

Perhaps the real F/A-18 does incorporate auto nosewheel steering engagement at touchdown (I don't know).  But if it does, it sounds like a dangerous feature that I would not be comfortable with.

[jaylw314]

5 hours ago, Reusenfisch said:

Hi, actually not. But as a retired  Militarypilot I find it very dangerous. All aircraft I flew had never the NWS engaged at touchdown. 

If you review the internetly available (but not postable) NATOPS for the F/A-18C, the rationale for having NWS on during the rollout (and minimizing rudder use in crosswinds) is laid out in the landing procedures sections.

What isn't in there, that is simply my speculation, is that the CG is much farther forward of the main gear than other typical aircraft, resulting in excessive directional stability once the main gear touches down.  As such, if you've been tracking the runway centerline correctly, the plane gets yoincked into alignment with the runway when the mean gears land.

[Jackjack171]

It is correct. Take a look at any USN F-18 HUD footage. At touchdown, NWS appears in the HUD. I'm not a Pilot, just a retired Navy Chief! It's LO Gain so it's not as unsafe as you'd think.

[Muchocracker]

it's explicitly mentioned to be used in takeoff in the checklists and automatically engages when the nose gear has WoW's at touchdown. 

[bbrz]

12 hours ago, Bob1943 said:

Former military pilot here as well (T-37, T-38, F-111, AT-33, F-100, A-37).  Completely agree with Reusenfisch regarding the danger of auto nosewheel steering engagement upon touchdown. 

On all airliners I flew, regardless if it's Boeing, Airbus or Canadair, the NWS is always engaged.

I never experienced any directional control problems during normal or xwnd landings.

Edited April 15 by bbrz

[EnzoF98]

15 hours ago, Reusenfisch said:

but correct me if I am wrong. 

Gets corrected, then disagrees. 

[bbrz]

9 hours ago, jaylw314 said:

What isn't in there, that is simply my speculation, is that the CG is much farther forward of the main gear than other typical aircraft, resulting in excessive directional stability once the main gear touches down.  As such, if you've been tracking the runway centerline correctly, the plane gets yoincked into alignment with the runway when the mean gears land.

Wrong speculation. This has nothing to do with CG.  See my above reply.

Edited April 15 by bbrz

[Hiob]

Well, if anything, we learn here, that being a former Pilot doesn't necessarily qualify you in anything other than the Airframe you were actually trained on and that RTFM applies as always..... 

Edited April 15 by Hiob

[Reusenfisch]

Ja ja Hiob is scho recht….

For me it is not a desirable feature. 

[Hiob]

1 hour ago, Reusenfisch said:

For me it is not a desirable feature. 

Depends on the Airframe I'd say. Some are so touchy that they basically tumble over when looking at the pedals (looking at you, Mirage F1), others are waaay more forgiving. At least in DCS (obviously I have no idea how they compare to RL). But what kind of fell under the table it that the NATOPS seem to mention reduced gain. We have no idea how much gain there actually is available). They don't seem to be worried about the Hornet.

[Reusenfisch]

Copy. Just a word about internet docs. I would be careful with announcing to look up confidential info. I know it can be tempting. You don’t know who else is reading theses forums. Food for thought 

[razo+r]

2 hours ago, Reusenfisch said:

Copy. Just a word about internet docs. I would be careful with announcing to look up confidential info. I know it can be tempting. You don’t know who else is reading theses forums. Food for thought 

Big Brother has been confirmed watching you

 

[Cab]

6 hours ago, Reusenfisch said:

For me it is not a desirable feature. 

Times and technology change. After about 45 years, I’d say it’s a non-issue.

[bbrz]

8 hours ago, Reusenfisch said:

For me it is not a desirable feature. 

A good pilot simply adapts to the airplane he's assigned to. 

Furthermore the weight on the nosewheel is usually only 5-10% of the whole airplanes weight, so nothing serious will happen IRL if the nosewheel isn't perfectly aligned, except nosewheel skidding.

E.g. 

 

 

 

 

5 hours ago, Reusenfisch said:

 I would be careful with announcing to look up confidential info. 

Confidential info???

Edited April 15 by bbrz

[Dragon1-1]

8 hours ago, Reusenfisch said:

For me it is not a desirable feature. 

Worth remembering: the Hornet is a carrier aircraft first. On the boat, you don't have any of those concerns that exist with aircraft primarily designed to land on a runway. So enabling NWS right after touchdown makes sense. Hornets come onto land relatively infrequently, and thus safe handling of extreme crosswinds was not a design parameter. Even then, they don't flare, so landing with pedals deflected doesn't pose as much a risk as you might think. Touching down at an angle isn't actually that much of a problem when you slam it down like the Navy does.

[Muchocracker]

The FCS turns the steering gains down with speed regardless. There is no reason to disengage the NWS on either takeoff or landings. 

Edited April 15 by Muchocracker

[Czar66]

23 hours ago, Bob1943 said:

Perhaps the real F/A-18 does incorporate auto nosewheel steering engagement at touchdown (I don't know).  But if it does, it sounds like a dangerous feature that I would not be comfortable with.

You have different planes in mind in which with that characteristic featured in the Hornet, would be indeed a bad idea. The rudders of the Hornet will also aero brake while performing very little deflections and the nose steer with a dynamic gain would benefit the control ability for the pilot.
Low gain is a very wide turn radius already, akin to the F-15E which also have nose wheel steering always on albeit turned off with a paddle switch press. Same as the Hornet, but here is a toggle instead of hold.

Designers could very well take advantage of the beefy nose gear to balance more towards mechanical control instead of aero after touchdown.
Nevertheless, all videos I've watched on Hornet landings throughout the years, they were always remarkably stable. Same experience I have on DCS. Easiest plane to land on a runway by quite a margin with the nose wheel steering always on after touchdown. The other would be the Tomcat, nose wheel steering off with that one as its systems doesn't feature a dynamic low gain.

 

10 hours ago, Reusenfisch said:

For me it is not a desirable feature. 

That's how the plane is intended to be. The rudders provide aero braking and deflect very little after touchdown so control could very well be degraded. Warbirds were even 'worse' by those standards when relying on differential braking to steer.

2 hours ago, Dragon1-1 said:

Hornets come onto land relatively infrequently

That is incorrect. Finland and Canada are among the countries that used/uses the Hornets extensively on runways. Switzerland too.

2 hours ago, Dragon1-1 said:

and thus safe handling of extreme crosswinds was not a design parameter.

The Hornet takes crosswinds better than F-16s... and planes made to land on carriers are notoriously easy to land and handle on land.

2 hours ago, Dragon1-1 said:

Even then, they don't flare, so landing with pedals deflected doesn't pose as much a risk as you might think. Touching down at an angle isn't actually that much of a problem when you slam it down like the Navy does.

They do. It is a directive made for american forces not to flare because of X, Y and Z. Other countries Hornets that are not operated from carriers nor expected to, flare on touchdown.

 

Edited April 15 by Czar66

[Dragon1-1]

1 hour ago, Czar66 said:

That is incorrect. Finland and Canada are among the countries that used/uses the Hornets extensively on runways. Switzerland too.

It's correct as far as our Hornet and this discussion are concerned. Their Hornets are modified to that end, their SOP is different as well. The export Hornet is not the subject of this discussion, because we don't know if their NWS is also set to come on automatically. It's very possible that it's not. Our Hornet's NWS logic is very distinctly carrier-oriented.

1 hour ago, Czar66 said:

The Hornet takes crosswinds better than F-16s... and planes made to land on carriers are notoriously easy to land and handle on land.

It's not hard to take crosswinds better than the Viper, which has a notoriously high landing speed, small rudder and narrow undercarriage. Also, Hornet's strong and relatively wide landing gear allow it to absorb a lot more sideways velocity. You can ride it all the way to the deck using an angled approach and it'll be fine.

The problem with using the rudder is that if you need anywhere near a full boot of rudder to get the aircraft to fly straight, it'll transform into a full boot of NWS when the aircraft touches down, which is not something you want even with automatic gain adjustment. Fortunately, the Hornet won't mind if you instead slam it down sideways, or if one of the wheels touches the ground a little earlier. So you shouldn't need large rudder inputs in first place, just let it straighten itself out.

USN Hornets land the way they do because they're carrier jets with carrier flyers driving them. It's always safer to do the landings in a consistent way, and in this case, that means as if you were on the boat. Crosswinds are not entirely unknown on the boat, BTW, just typically smaller than on land.

Edited April 15 by Dragon1-1

[jaylw314]

14 hours ago, bbrz said:

Wrong speculation. This has nothing to do with CG.  See my above reply.

That you've flown a lot of airliners?