Beechjet Anti-Skid Off on the Rollout???

[Aspiring to be]

First let me say that I know nothing about the Beech Jet. I am also not trying to defend the action of turning off the anti-skid during rollout.

I am saying that some airplanes do require you to turn off the anti-skid at low speeds. This is for taxi and coming to a smooth complete stop. I know most if not all modern airplanes have dependable automatic systems that us a minimum tire speed for activation. I have seen several times where the auto system failed. But there are some aircraft that do suggest turning off the anti-skid. Most after landing (not securing) checklist call for anti-skid off. Most airplanes, even the heavy ones have anti-skid on one hydraulic system.

I recall one time I landed and the brakes went into max breaking. The aircraft had auto brakes but they were selected off as we were not required to use auto brakes unless we used auto land under Cat 2 or 3 conditions or we just wanted to. The flight engineer selected a different hydraulic system there by releasing the auto brake anti skid system. It felt like we had hit the afterburners when he did that.

I do like when I am on a contaminated ramp to turn the anti-skid off even if the after landing checklist does not call for it. I started doing this due to the fact that several times I have had the antis-skid to release the brakes when they should not have at very low speeds.

I will add that if you have landed and think that you need to turn off the anti-skid to stop on the runway then you have more problems than I can think of. MAX breaking can only be achieved by using the anti-skid system. My way of thinking if you are using the anti-skid to stop you should be in an emergency situation such as a high speed abort. If you need max breaking you have made several mistakes or you must be in an emergency situation. The occasional activation of anti-skid is normal, i.e. landing on a contaminated runway and at low speeds.

Correct procedure in my opinion is that brakes should not be used on a contaminated runway until you are below hydroplane speed and I would recommend for you to be 10-15 knots below hydroplane-speed. Aero-dynamic braking should only be used on a contaminated runway until below hydroplane-speed. My old company whom had several heavy types used 100 knots or below prior to using brakes on a contaminated runway. I believe this to be a very good procedure. If the conditions and field length does not allow this then you need to go elsewhere. In many years of flying I have felt the release of brakes by the anti-skid system only a few times. The anti-skid and max breaking is truly great in a high speed abort.

I use to wear boots!! Think they are great. Just be careful of the heal type as some can get caught below the rudder peddles.

 

[proav]

In my opinion, if not using the anti-skid would help you stop sooner wouldn't all the manufactures save a lot of money and increase safety by simply NOT installing it on their aircraft?
Common sense should tell us that anti-skid is there for a reason.

 

[IronManNDFW]

No Brain'er

In the CE series and HS & BAE that I have flown (and instructed) are all the same, when you purchase the aircraft you turn it on and leave the A/S on. The only time you turn it off is when you sell the airplane.

The new buyer turns the A/S on and leaves it that way until they sell it! You starting to see a reoccurring pattern?

Yes, there are procedures for NO-A/S landings, you usually will only try it once, but if you do, please read the directions & add the additional runway landing length required. Once you see how much it adds to your landing, you will see very quickly how much A/S is needed. Do it in the sim if you want to see what it is like, my guess is you'll blow the tires (you will if I'm running the panel in the sim).

Some aircraft will not allow A/S operations below certain airspeed. It doesn’t mean that you can turn the switch off! In the heat of a take-off at some locations (TEB, HPN) you may forget to turn it on, and if you needed to make a High Speed abort… Well you get the idea.

But do remember this if it can be MEL'ed FOLLOW THE WRITTEN PROCEDURE, lest ye be brought before the judge and explain how is it with you vast aviation knowledge you purposefully created a violation of the FARS by not following written procedures. They usually will try to charge you with wreck less and dangerous, and take certificate action.

 

[Aspiring to be]

"Yes, there are procedures for NO-A/S landings, you usually will only try it once, but if you do, please read the directions & add the additional runway landing length required. Once you see how much it adds to your landing, you will see very quickly how much A/S is needed. Do it in the sim if you want to see what it is like, my guess is you'll blow the tires (you will if I'm running the panel in the sim). "
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Sorry but I do disagree with you. Your running the sim has nothing to do with anything. A landing without A/S is no big deal on a dry runway. In fact if the A/S comes on when landing on a dry runway then something is bad wrong with your procedure. A/S activation on a contaminated runway is understandable on occasions. I believe that if you have to use max effective breaking in other than an emergency situation (abort, overweight landing) you have placed yourself somewhere you should not be. I have made many landings with poor braking action reports without having the antiskid to activate. I have also instructed in the sim before and find your statement about blowing tires to be way off. I have flown large equipment in some very bad weather and very seldom had the A/S to activate. I fully understand that max breaking can only be achieved by using the A/S to stop hydroplaning. As you know there are different types of hydroplaning and hydroplaning can occur on a dry runway.

Several months ago I landed a small jet with only accumulator breaking, of course no A/S available. I have made landings in large aircraft without A/S. I have made and seen many landings in a sim. without A/S. With all of these cases I have never had a tire to blow. What I am trying to say is that it is not a big deal. I have made many and sure you have also made landings and never touched the breaks until a slow taxi speed. Additional runway required, yes, how much, not near as much as your post would indicate. No I would not take say a Hawker into a contaminated runway of 5000 feet without A/S; I would on a dry runway. My why of thinking A/S will prevent hydroplaning and give max breaking effectiveness on a contaminated runway when landing. Will help stop flat spotting a tire on landing. Will give max breaking on an abort with a chance of not blowing the tires. Many high speed aborts will result in tires blown due to the heat build up and the fuse plugs blowing.

"Some aircraft will not allow A/S operations below certain airspeed. It doesn’t mean that you can turn the switch off! In the heat of a take-off at some locations (TEB, HPN) you may forget to turn it on, and if you needed to make a High Speed abort… Well you get the idea."
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Many of the larger A/C will call for the A/S to be selected off on the after landing checklist. If you have complied with all checklists i.e.: before takeoff the A/S will be placed in the on position. Not being smart but your same logic would say to leave the gear down at all times so in the heat of landing you will not forget to extend the gear. I realize that on the newer equipment you do not have to turn the A/S switch off. I believe that prior to every engine start you must assure that all switches are set to the correct position. Have you ever left your flaps up when you taxi out on a contaminated taxi way. Good procedure would call for you to put the flaps down after the taxi out. Just getting in the seat I have moved switches, had owners/passengers to hit a switch. I have also made PA announcement over the ATC system. This was easy to do when you are use to a DC-9 and B-727 with their separate PA mike and then get into say a 757 with one mike. I like to turn off the A/S at slow taxi speeds on a contaminated ramp. I have seen to many A/S and other automatic systems fail.

 

[Diesel]

Aspiriring I can't tell what you were saying. I'm not sure if you were quoting something or what you were saying.

A/S in a citation puts a annuciator light on the panel. Anything below 15-12kts turns the a/s off. Why would you turn the a/s off? The ntsb would love the fact that you turned the a/s off right before you slid off the runway.

If the system fails it fails. At least the switch will be in a position it was supposed to be in. Check the numbers for a landing anti skid off. It's a long number.

We aren't talking 75''s and that sort. We are talking beechjet's and that size.

 

[Aspiring to be]

Never turn A/S off on rollout!

Aspiriring I can't tell what you were saying. I'm not sure if you were quoting something or what you were saying.

A/S in a citation puts a annuciator light on the panel. Anything below 15-12kts turns the a/s off. Why would you turn the a/s off? The ntsb would love the fact that you turned the a/s off right before you slid off the runway.

If the system fails it fails. At least the switch will be in a position it was supposed to be in. Check the numbers for a landing anti skid off. It's a long number.

We aren't talking 75''s and that sort. We are talking beechjet's and that size.
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I was not trying to be disagreeable. In a previous post I said that you should never turn the A/S off to improve stopping distance. The min stopping distance is achieved by using max braking and let the A/S work to prevent hydroplaning. That is an undeniable fact.

I was responding to a post where the person said that it would take a lot more runway and you would probably blow your tires. This is just not true. On a dry runway using normal procedure you should not have any trouble. I will say again that if you cause the A/S to active on landing on a dry runway your procedure, well sucks. I do not care if you are flying a B-747-400 or a Cessna. If you land other than an emergency condition and have to use max breaking thereby requiring the A/S to prevent hydroplaning you have made the wrong decision or selected the wrong airport. I stated that landing on a contaminated runway the activation of the A/S can on occasion occur.

Yes landing without A/S requires more runway but a clean runway it is not that much and you should not blow your tires. Can you blow your tires, yes, but to me the real danger or concern about landing without A/S is flat spotting a tire. Some of the larger aircraft even with A/S you can still flat spot a tire. Flat spotting a tire and blowing a tire are two different things. Like I said I would not land a Hawker without A/S on a contaminated runway of 5000 feet or less but I would land without A/S on a dry runway of 5000 feet.

If you look at the numbers say for a Hawker, landing wt. 21000, standard day, sea level, calm winds the landing distance is 2473, landing field dry is 4121, landing field wet is 4740. You can almost land the Hawker on a dry runway of 5000 feet and landing weight of 21000 lbs and never use breaks. If you land without A/S the penalty would be applied to landing distance and not the landing field. It would affect the landing field but the penalty would be applied to the landing distance. Why anyone would ever think that max breaking would be normal is beyond me. Have you ever had the A/S to activate on landing on a dry runway? I do who hope not.

My previous response was to the poster that said it was such a big deal and that you would blow tires, etc. Sorry but I believe that is just not true. I would be willing to make a bet that I could land and stop any aircraft with reasonable runway without A/S without blowing a tire. I am not the ace of the base and I hope that most pilots could do the same. Yes if I was operating the sim I could hit the button that says blown tire but that is a compound problem and not one that should be cause by the fact that you landed without A/S.

Now bottom line and I state again you should never turn the A/S off in any aircraft to decrease stopping distance. Min stopping distance is achieved by using max brakes and allowing the A/S to prevent hydroplaning thereby given you the min stop distance.

I do believe that landing on a contaminated runway you should as a normal procedure use aerodynamic breaking until you are well below hydroplaning speed for your aircraft before using any brakes. If you find that you must use brakes above hydroplaning speed you again are some place you should not be. I only made the statement that on contaminated ramp I like to turn the A/S off due to the fact that I have seen the A/S activate at low speeds where it was supposed to be auto off. I am not saying that I think it should be normal procedure. I am saying that I do that and I will continue to do so. I have several things that I do that I do not expect all to do, I am sure all I do is maybe not the best thing. Many times as I approach a gate where the ramp is very slippery I will open the reversers and even use reverse thrust when on a down slope. I have had to do this several times on large aircraft to be able to stop without hitting the terminal.

It might not be a procedure in the book but I know that most all aircraft with reversers will back up. Now I am not saying that backing up an aircraft is normal procedure but in some aircraft it is approved procedure. I also am not trying to give lessons, but I do not believe that landing without A/S is a big deal. I do not believe that landing without A/S will mean that you will blow your tires. I do believe that taking off without A/S is a much bigger deal. I would want a bunch of extra runway for takeoff. I do not believe in scare tactics such as you will blow your tires. I do not think the poster really meant it as a scare tactic but that is the way it came across to me.

Normal abort procedure will be changed. Some types (maybe only larger types) use auto brakes for abort, without A/S you could not arm the auto breaks. All of the auto brakes that I can think of are activated by reverse thrust above 80 knots. Not being able to touch the brakes on abort is difficult when you first start training in such a system.

Gereral statement never land an aircraft with 4 mains or more with more than 1 A/S release light on with the A/S on. Never land an aircraft with only 2 main wheels with any A/S release light on with the A/S on.

While flying with some of the younger pilots the biggest fault that I find is the reliance on auto systems and computers. Steam gauges still work for me and I believe in them.

 

[BigFlyr]

Boy you guys are long-winded! Here's what this guy's thinking about turning off the anti-skid... Locked-up wheels produce more friction than rolling wheels on dry pavement, so therefore an airplane should stop sooner with the wheels locked up than rolling. The problem is, the wheels cannot maintain this condition for long due to heat build-up and the eventual tire failure, in which case the end result is longer (and more expensive) stopping distance required.

 

[Aspiring to be]

Not really true. You can hydroplane on rubber so it depends on the speed you lock up your brakes. I do not believe that you can not stop quicker when you are skidding. Maybe from a very low speed it would be true. Tire failure as I have seen, from heat buildup, occurs several minutes after the braking action is completed. This is one reason for fuse plugs. Fuse plugs will blow when the heat build up is sufficient and save the damage that could result if the tire blows from heat buildup; a control blowout is really produced.

I have seen it take 10 or 12 minutes after landing for a fuse plug to blow. One case I remember I met the aircraft at the gate and had started a pre-flt and was in the area of the gear when a fuse plug blew, scared the hebe gebbies out of me I can tell you.

 

[BigFlyr]

Not really true. You can hydroplane on rubber so it depends on the speed you lock up your brakes. I do not believe that you can not stop quicker when you are skidding. Maybe from a very low speed it would be true. Tire failure as I have seen, from heat buildup, occurs several minutes after the braking action is completed.

True... Eventually the tires could start hydroplaning on boiling rubber, until there was no rubber left, to be followed by a blow-out. Then there is the other kind of blowout due to a melted fuse plug, but this has nothing to do with the anti-skid system and more to do with landing at excessive speeds or insufficient rollout which will overheat the plugs to save the tires from exploding.

In any case it is never recommended to turn off the anti-skid for normal takeoffs and landings. It is, however recommended to be turned off for taxi in some aircraft... where much lower speeds are involved.

 

[TAG2]

I hesitate to jump into this mess, but here goes. Back to the original question of some BE400 guy saying to turn off the anti-skid if things get hairy. He probably flew the old Diamonds (MU300) without T/R's. If you have ever flown one you would know the brakes suck. On a contaminated runway, they WILL cycle and once they do, you have no choice but to stay on them unless you have a really long runway in front of you. The 1st cycle is a lonnnngggg one. The brakes just realease and you count to 10 (seems like) waiting for your brakes to come back. When they do, you need to apologize to you pax for the series of whiplash maneuvers. The problems were pretty well worked out in the Beechjet. I do know guys that would turn the A/S off if they got scared in the MU300 but to tell a new Beechjet crew to do it is not right.

 

[MooseTrax]

AntiSkid

If the performance was better without anti-skid, then why did we ever put it on airplanes? The fact is the performance is greatly enhanced and this guy is taking a real chance.

 

[100LL... Again!]

Other possibility for why this stuff happens:

Some guys have a deeply held need to be smarter than the test pilots, engineers, whoever.

Book calls for .76M, they have some co 'n bull reason why .77M is far superior. The rules/methods change on every leg, so that you can never figure out their black magic. Wearying.

Not necessarily true in this case, but it happens all the time.


Quote from rice:
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Here I sit just shaking my head!
Some yahoo is out there flipping off the anti-skids for apparently no good reason, flat-spotting tires, costing some company lots of dollars and generally making a fool of himself.
And I'm sitting here behind this f%*$en geek machine for the 76th day after being laid off!!!!!! Some things just aren't right in this world.
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Amen.
The weed-out process in this biz never seems to work properly does it? I feel your pain.