Beechjet Anti-Skid Off on the Rollout???

[abenaki]

Could use some input from some Beechjet drivers......

Was talking with some friends today who operate a brandy-new Beechjet. This is their first jet after operating pistons and some turbines for a number of years. Their contract pilot has a "technique", if you will, of choosing to turn off the anti-skid if he looks like he's coming up a little short on runway. His rationale' is that if it looks like he's going to run off the end, it's better to lock up the brakes to avoid doing that. Apparently he did it the other day and flat-spotted two tires to the tune of some major bucks.

Now, this is one I've never heard of anywhere including FSI and flying several planes with anti-skid systems......I figure the best deceleration under ANY circumstances is with the anti-skid on letting the computer set the braking pressure just this side of impending lock-up. Skidding will ALWAYS increase distance used, will it not? I cannot fathom a scenario where turning OFF the anti-skid is going to help.

I figured this "technique" was just another one of those bizarre rationalizations that just don't add up to anything but a lot of hu-ha. Something like the RJ guy I knew who used to used the speed bakes in the flare or the X guy who pops the reversers before the nose-wheel touches down.....not the best idea in a X.

Your comments would be appreciated.

 

[2000flyer]

While not having flown a Beechjet, I just can't imagine turning off the anti-skid system in any aircraft for landings. Sounds like this chap got some bad information somewhere, or devised a bad rational of his own.

I'd hate to see the NTSB final report on this guy should he blow the tires....then run off the runway and they find a perfectly good anti-skid system in the OFF position.

I'd be interested to also hear from Beechjet drivers if this is a common practice.

Regards,
2000Flyer

 

[rice]

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.

Sorry guess I just needed to vent.

Y'all have a nice day now,

Rice

 

[stingray]

Who ever is telling your friends to turn off the anti skid is on Crack?
Lets turn it off, so we can now blow some tires. Which almost Happened to them. (2 flat tires)
Turning off the anti skid actually increases the landing distance. (check the numbers)

with the anti skid ON you can get on the brakes as hard as you whant and the brakes should not lock up. (Maximum braking without locking up)

If this guy is ending up with a little less runway sometimes, (Why is that?), does his approachs suck to begin with, extra speed, coming in hi, or floating down the runway to grease it. (doesn't know when to do a go-around) maybe
It sounds like this guy teaching your friends has some piss poor techniques. Keep The Anti-Skid ON

 

[LrBob]

hell blowing a couple of tires in the bahamas sounds like a good idea-a margarita please

 

[Joe Jet Pilot]

What?

Tell your friends to find a new contract pilot. In the beechjet, you do not have anti-skid if the wheel speed is below 24 knots, if I recall correctly.

What some people will do is taxi with the anti-skid off if the breaks are grabby.

All of the normal performance charts are based on anti-skid being on. PM me if you need any additional info.

 

[helpmerhonda]

I would definitely second what joe joe pilot says. You don't want to fly a Beechjet with out the anti skid on or inop condition. You can turn it off for taxi to and from the runway but last before take-off item or call is annunicator panel is clear, ie antiskid light is out. On landing, aircraft at 50 ft over numbers should be Vref and throttles going to idle. Every 10 kts over Vref is equal to 1000' of runway consumed before touchdown due to float. Bechjet landings are easy to grease on compared to the Citation CE-500 thru CE-560 Ultra aircraft. Good idea to dump the yaw damper at 50 ft as well otherwise its difficult to make a highspeed tawi way exit with it on. Dump the yaw damper early like 500 agl and the airplane behaves like a V-tail Bonanza in turbulance. The owners need to get themselves a new pilot who not afraid to make a go-around when things are not quite right. Any way, that's my .02 cents worth.

 

[DLF8108]

YES, KEEP THE ANTI-SKID ON (Beechjet Anti-Skid Brakes)

Flew the T-1A (USAF version) for three years. That model had Anti-Skid protection at speeds greater than 14 kts. The APPROVED braking technique (per the AFM) was to maintain continous pressure on the pedals and let the A/S do its job.

From personal experience, you could feel the A/S cycle if you pressed too hard above 75-90kts (depending on gw)...below approx 60kts at all gross weights the A/S power brakes worked VERY well & the acft decelerated quite nicely...A/S hardly ever cycled at all.

Unless faced with a multiple-emergency or situation wherein the AFM has no guidance...I would FOLLOW THE AFM.

DLF8108

 

[hawkerjock]

The only time I know of to turn the antiskid off on a landing roll is if the brakes are not working. However after 3 long seconds you are to place the antiskid switch back to on and 9 times out of ten the brakes will be there. Seems to be a bigger problem in the Diamond though. Sounds like this guy is jumping the gun a bit.

 

[irapilot]

I think he could get the aircraft to stop sooner if he just left the gear up, right? I mean, it is the same logic almost as turning the anti-skid off. May as well just unfasten your seatbelt too.....might speed the egress from the aircraft.

My gawd, it always blows my mind when pilots "re-invent" the wheel.

 

[learflyer]

sounds like the type of pilot that wears cowboy boots with his uniform as well. Sorry guys, just an observation!

 

[yosemite]

learflyer said:

sounds like the type of pilot that wears cowboy boots with his uniform as well. Sorry guys, just an observation!

Is this an informed observation or are you just shooting your mouth off?

Tell me the difference in boots worn? Which are wrong or right?

Are you refering to the Justin Roper types offered for sale by Sportys and any good western wear apparel place... Or are you talking about pointy-toed, snake-skinned, boot cut types?

I can tell you this from experience. I've been raised in a part of the country that wears boots regularly. I've worn them for 30+ years (longer than I've been flying) and have worn the Roper style off and on while flying for years.

First, I would unequivically(sp?) state that the stylish/fashion type boots (specialty skins, pointy toes, boot heels instead of walking heels, etc..) ARE NOT proper for aviation use. They are not professional in appearance.

However, the Roper styles are made of quality leather which is practically unexcelled for foot protection, are low-rise and round toed which make them very conservative in appearance, are made of a very soft and supple leather so they are EXTREMELY comfortable to wear for extended periods, hold a shine nicely if tended to like any other quality footwear product, protect your foot well from the elements found on a winter ramp, and of the most interest to Mr. learflyer... have kept my feet warm and toasty many a time when my buddy in the other side of the Lear cockpit was whining up a storm about how cold his feet were.

So just because someone wears boots in the cockpit, don't take it for granted that they are a Texan (I sure ain't!) and they are a cowboy hick (I am, without question, not!)... and please remember that it is better speak with experience than with your foot in your mouth.

 

[firstthird]

I agree, if you got it, use it. The it being anti-skid, I surely can't cycle the brakes 8 times a second or whatever the computer does.

That being said, the poster said that skidding always increases the distance to stop. I'm not sure about the Beech but cars can stop faster without it in one special case, that being a few inches of snow rather than ice. ABS tends to do a little cycling when there is enough snow to make it a little slick but if you were able to lock them up your car tires become like snow plows piling up the snow and increasing the friction as more snow piles up. It isn't very often when this is the case because ice underneath and the type of road you're on probably make a difference. But, because of this phenomena I'm think some car companies have buttons where you can turn the ABS off if desired. Anyway, this is about planes not cars so I'll stop here, and if the Beech has the ABS locked out below 20 knots, then I think the piling up snow theory doesn't work for an aircraft.

 

[Joe Jet Pilot]

Well Can't Speak For Cars

I have flown the Beechjet for several years now. When the anti-skid switch is placed from on to off, there will be a period of 3-5 seconds where you WILL NOT have any brakes at all. Anyone who flies the Beechjet should know this as testing the antiskid is part of the taxi check. Besides what the heck is someone doing looking for the switch during a critical phase of flight anyway. There is only one failure in the beechjet that will result in having no brakes at all, and that is the lose of both transducers.

For someone to decide during the rollout with TR's deployed that oops, I may wind up short, I'll turn off the anti-skid is just plain stupid. There is no way around it!

To abenaki:

Tell your friends to ditch this contract pilot before he kills someone!

 

[CL60]

Test pilot?

This one is easy.

Is this guy a test pilot? If not, then what is he doing performing an unauthorized procedure? Can the aircraft be dispatched without operational anti-skid? Does the manufacturer recommend turning off the A/S for short field landings? Is it an approved procedure? I hate hearing about incompetent pilots who make up their own rules as they stumble along.

This story reminds me of the fool in Redmond, CA. who tried to takeoff in a Corvette with only one operational engine. Ever heard of VMCG/A dummy?

 

[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). "
___________________________________________________




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."
____________________________________________________

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.
_________________________________________________

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:
---------------------------------------------
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.
---------------------------------------------

Amen.
The weed-out process in this biz never seems to work properly does it? I feel your pain.