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  1. #1
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    Default Aerial Set-up Restriction on Sloping Grade

    Has anyone ever heard of restrictions regarding setting up an aerial on a slope parallel to the axis of the chassis? Specifically, one manufacturer (one of the top 3) cautions against setting-up their aerial on a slope (cab facing down hill) and subsequently operating the stick over the cab. This configuration apparently has the tendency to create a "teetering" effect .......WTF ?

    I assumed that as long as you were able to get the chassis of the truck reasonably leveled, you would not be restricted outside of normal operating restrictions (loads and angles) since the truck should be balanced with the loads being transmitted to the ground from the outriggers and the outriggers only.

    LDR20TRK


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    Forum Member jlcooke3's Avatar
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    All manufacturers have restrictions when operating on any type of grade. The reason for the restriction for operating on a lateral grade over the front of the apparatus is a shift in the center of gravity to the front end of the truck. Check out IFTSA's Aerial Apparatus operator book it explains center of gravity and stabilazation better.

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    I realize that there are obviously restrictions when operating on grades. The question is whether there are restrictions if the truck is close to level while operating on a downhill facing grade. Putting it more simply, I parked the truck facing down-hill on a 10 percent grade with the ladder target straight ahead. After setting the outriggers/stabilizers, the front tires are about 18 inches off the ground. The truck is level front-to-back and side-to-side. Should there be any restrictions with operating the aerial straight over the cab ?

    LDR20TRK

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    While this may sem extreme, I belive it has to do with the ground contact points. The weight is still being transmitted to the ground and will no doubt "push" toward the lower side. I've heard of 'scopes sliding on hills in ice conditions. While the grade may have to be very steep to do this in dry conditions it has to have an effect on the amount of down pressure not being even (as designed). Everyone has to set limits in todays world or they'd be sued out of existence.

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    The short answer is that as long as the truck is level, there are no restrictions. Use the two levels to make sure the truck in level, both front to back and side to side.

    A couple of warnings:
    1) When operating on a slope, especially the one you described, keep the ladder in line with the truck body, i.e. operate over the front or rear. Extending to the sides will cause the ladder to twist and transfer to load to the side of one beam. Aerial ladders can and will fail when side loaded like this.

    2) Check your ladder truck operators manual. Some vehicles makers require all tires to maintain ground contact, others allow you to lift the wheels off the ground.

    We run a Pierce 105' rear mount. There is are hill we cannot setup on if we are facing downhill, put can setup on if we face uphill. The truck has to have all tires in ground contact and with the outriggers in the rear, we are limited in how much we can adjust when facing downhill.
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    Forum Member jlcooke3's Avatar
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    Stabilizers are used to increase the center of gravity of the vehicle while operating an aerial device. Anytime that you transfer enough weight past the "circle of gravity" created by the stabilizers you run the risk of a tip over or other equipment failure. Setting up on a downward facing slope and operating over the front of the vehicle you run a greater "chance" of a failure. Why? First off facing downhill the weight of the vehicle has been transferred to the front axle (which is typically, though not always) outside of the circle of gravity created by the stabilizers. Even though the vehicle levels out with the use of stabilizers more weight than normal is now be placed on the front stabilizers, operating over the front may exceed their capabilities. On downward facing slopes you should operate over the rear of the apparatus not the front or sides. On upward facing slopes you should operate over the front not the rear or sides.

    The short answer is that as long as the truck is level, there are no restrictions.
    That's a load of crap...ever heard of short jacking. Operating on slopes is equivalant to short jacking you are reducing the operating capabilities of the machine.

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    On certain apparatus, there is a sensor on the front axle. When the front axle is lifted off the ground the sensor activates and Aerial Ops stop until you use the over ride control to either Put the front wheels back on the ground or continue what you were wanting to do. Having the stabilizers and the front wheels on the ground create the "stable Base" for your operations. The teeter-tooter effect you speak of was mentioned to me by the enginner that came to do our training on our new aerial (2005 Pierce 100' PAP). If this was to happen you could have a catstrophic failure due to having the front end slapping the ground. Something its no supposed to do. I hope this helps. He also specifically mentioned doing just the opposite of what you asked. Facing uphill and working over the back getting the teeter-tooter effect.

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    Quote Originally Posted by jlcooke3
    That's a load of crap...ever heard of short jacking. Operating on slopes is equivalant to short jacking you are reducing the operating capabilities of the machine.
    The question did not mention short jacking, so I do not think my answer is a "load of crap". The operators manual for our ladder states that when operating on a slope, with the jacks fully extended and the lateral and longitudinal indicators in the center of the green, that 100% of the ladder capacity is available. The limits on use come into play when the indicators are in the yellow (50%) plus the inherent danger of operating any aerial device perpendicular to a slope, i.e. cab of the truck facing up hill, the ladder at a 90 degree angle from the body.

    My town is very hilly, we train our aerial operators to always approach from the bottom of the hill in order to maximize the leveling capabilities of the aerial. We try to use the ladder either over the cab or within 45 degrees of the cab when on a hill.
    Last edited by KenNFD1219; 06-18-2006 at 04:19 PM.
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    Forum Member DeputyChiefGonzo's Avatar
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    Quote Originally Posted by jlcooke3



    That's a load of crap...ever heard of short jacking. Operating on slopes is equivalant to short jacking you are reducing the operating capabilities of the machine.

    Food for thought... one cannot short jack an E-One aerial.
    ‎"The education of a firefighter and the continued education of a firefighter is what makes "real" firefighters. Continuous skill development is the core of progressive firefighting. We learn by doing and doing it again and again, both on the training ground and the fireground."
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    Forum Member Rescue101's Avatar
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    Or,just to stir the pot,how about a Metz with a self leveling turntable?The safeties on the Metz will not allow you to exceed either "short"jacking or operation outside grade restrictions.Having run one "short"jacked I can tell you there is still a LOT of reach on the short side.On ice,even the best jack system can move if the grade/elevation is right. Interesting discussion. T.C.

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    MembersZone Subscriber N2DFire's Avatar
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    Quote Originally Posted by KenNFD1219
    The operators manual for our ladder states that when operating on a slope, with the jacks fully extended and the lateral and longitudinal indicators in the center of the green, that 100% of the ladder capacity is available.
    Ahh haa - the key words here are "operators manual for our ladder" - Your ladder isn't their ladder. Every Mfg. has different requirements - even different styles from the same Mfg. have different operating parameters.

    Quote Originally Posted by LDR20TRK
    I realize that there are obviously restrictions when operating on grades. The question is whether there are restrictions if the truck is close to level while operating on a downhill facing grade. Putting it more simply, I parked the truck facing down-hill on a 10 percent grade with the ladder target straight ahead. After setting the outriggers/stabilizers, the front tires are about 18 inches off the ground. The truck is level front-to-back and side-to-side. Should there be any restrictions with operating the aerial straight over the cab?
    The most correct short answer to the question.
    Quote Originally Posted by KenNFD1219
    2) Check your ladder truck operators manual.
    Take Care - Stay Safe - God Bless
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  12. #12
    Forum Member jlcooke3's Avatar
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    Quote Originally Posted by N2DFire
    The most correct short answer to the question.
    Quote:
    Originally Posted by KenNFD1219
    2) Check your ladder truck operators manual.
    And that was what I was getting at. Simply stating because an aerial is level doesnt mean that there are no limits on its operation.

    Capt I can see how the E-One aerial's with the underslung stabilizers can't be short jacked but what about the ones with out and down stabilizers i.e. the HP75 and the HP105 platform?

    And KenFD1219 I should have stated it better in my other post.

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    True, but gravity doesn't check truck make before attracting things to the ground. If you set up downhill, and operate over the cab of the truck with the front end off of the ground, the front stablizers will act as a pivot point, and when enough weight is transferred to the downhill side of the truck over the cab, it will put the front end on the ground and lift the back end up. Bad things happen when gravity wins.

    The exception being those trucks that have front stabilizers like the Scopes and some others. But many don't have the length to reach down a few feet to make sure the front end is stable if you run the truck to within the 5 degree tilt from front to back, the front will still be off the ground if you're on a ~3+ degree slope.

    Facing uphill keeps 6 points of contact on the ground and doesn't allow for pivot points (front tires, 4 outriggers). But as TC mentioned, if the ground is slippery enough the whole truck will walk downhill, even if you put down wheel chocks around the front tires. There won't be enough fiber in Walgreen's to cure your pucker factor if that happens and you're on the aerial.

  14. #14
    Forum Member Rescue101's Avatar
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    I've never personally seen the condition with fire apparatus but I did see the results of it happenong to a tractor-trailer log picker.There was a brown streak from the log pile to the final resting place against a big bull pine at just about the center of the log loader seat.So I've added it to the toolbox under dumb s**t you should NEVER do. T.C.

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    Forum Member Bones42's Avatar
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    I bet there was a brown streak in the operators shorts as well.
    "This thread is being closed as it is off-topic and not related to the fire industry." - Isn't that what the Off Duty forum was for?

  16. #16
    dazed and confused Resq14's Avatar
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    Quote Originally Posted by jlcooke3
    Capt I can see how the E-One aerial's with the underslung stabilizers can't be short jacked but what about the ones with out and down stabilizers i.e. the HP75 and the HP105 platform?
    Has nothing to do with underslung or not. The control system prevents the electric-over-hydraulics from lifting the ladder out of its bed unless there is appropriate ground pressure on all four outriggers. When the aerial is flying, should the center of gravity shift causing one or more outriggers to have weight removed off of them, the aerial remains operational for safety's sake.

    That said, you can always be naughty and short jack (with the underslung this translates to only deploying one side of outriggers), then use the manual aerial hydraulic valves... not that it's a user-friendly way of doing business.

    TC - your flying shopping cart's "safeties" are all well and good, until one of them doesn't do what it's supposed to do. You're becoming accepting of new-fangled gizmos and gadgets in your old age... who woulda thunk it? The only flying in shopping carts I do is at Hannafords or Shaws... and even then it's a stretch to get me in those places.
    Last edited by Resq14; 06-20-2006 at 06:51 PM.
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    Forum Member Rescue101's Avatar
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    14,Read your own response.Your "beer can" has it's own set of electronic safeties.As far as I've been able to research there has never been a failure of Metz electronics resulting in injury to personnel or damage to the machine.Whether or not you like the "shopping carts"is irrevalent.They are a pretty intricate piece of machinery that can do some things a lot of "our"aerial devices don't do as well;and QUICKLY.Are they the device for everyone? Not hardly. But look at the wide range of angles that can be operated on,it's pretty impressive.Now one of the features I really like on the E-one buckets is the ability to tip the bucket under the boom,makes slicing a roof childs play.Most of the others don't work this way,the shopping cart included. T.C.
    Last edited by Rescue101; 06-22-2006 at 09:23 AM.

  18. #18
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    Default E-One

    To respond to the comment on the E-One not being able to short jack, I have this to say: First off HP75 HAS the ability to short jack and it also has the capability to short jack both sides and have 10% operation off each side to assist in an alley.

    The HP100, the CR100, the HM100 and the HP95 platform all have a jack spread under 14'. The HP100 (the most common 100' straight stick) has a 12' jack spread. The thing to note about the jacks on these units is that they are underslung and they can be slid under a car if nessary. That being said there is not many places, if any, that another manufacturer can set up there truck that an E-One can't. Also there are alot of places that any other truck will have to short jack, where an E-One can fully jack.

    Also the E-One torque box is so strong that they dont have to use a counter weight like so many manufacturers do, that may be the teeter-totter effect you are experiencing.

    Just another note is when you are looking at the strength of a torque box, look at the distance between the cab and the body when the truck is jacked and when its not, you will see alot of flex in all the other units. Also ask them to open the doors when the truck is fully jacked with the cab off the ground to see how much pressure is transfered to the body from the torque box. Oh and YES I am an E-One fan, so be kind!!

  19. #19
    dazed and confused Resq14's Avatar
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    Quote Originally Posted by Rescue101
    14,Read your own response.Your "beer can" has it's own set of electronic safeties.
    Never said *I* didn't trust them... It's just that I 've never taken you to be a fly-by-wire kinda guy....



    (and yes I'm just kidding around)
    Last edited by Resq14; 06-22-2006 at 06:45 AM.
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  20. #20
    Forum Member Rescue101's Avatar
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    By choice I'm not.However in this day and age it's Virtually(snicker)impossible to get equipment that isn't fly by wire.And certainly not limited to fire apparatus;planes,boats,tow trucks are all going that way.T.C.

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