Brakes (On or Off)
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Brakes (On or Off)
This is a question for all the boys who fly wheels.
I would like to get your opinion and the reasoning behind your choice as it applies to this question.
You are on final approach to any area where a rolling landing is not possible. (i.e. rig, helipad, confined area, etc) Is the parking brake "on" or "off " on final approach.
Cheers
I would like to get your opinion and the reasoning behind your choice as it applies to this question.
You are on final approach to any area where a rolling landing is not possible. (i.e. rig, helipad, confined area, etc) Is the parking brake "on" or "off " on final approach.
Cheers
For N Sea ops the SOP is brakes on and nosewheel locked for rig/ship approaches. For airfields brakes off/nosewheel unlocked. In the old Whirlwind it didn't matter if the brakes were on or off!!!!
HF
HF
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Brakes off, unless you really really can't roll at all.
Learned this while landing on a large pad at Max AUW. Building near pad blanked my headwind low final, decreasing performance shear, tried to slow it down with full intermediate, landed about 12 deg nose up (15max) about 15kts ground speed with brakes on. Couple chirps and then the nose really wanted to come down.
Hindsight, leave brakes on would have rolled very little.
Of course totally preventable if I realized what was going on earlier, but sometimes you don't realize these things. Brakes off gives you a few more options.
_______________
Here's a thought for everyone. When Winnipeg was flooding I was flying 6,000lb loads of sandbags from a muddy location to a distant dyke. Picked up load, wheels sank in mud. Trying to rip mains out of ground, I got very very close to dynamic rollover.
Question: Would the wheels have released more easily if the brakes were off?
Learned this while landing on a large pad at Max AUW. Building near pad blanked my headwind low final, decreasing performance shear, tried to slow it down with full intermediate, landed about 12 deg nose up (15max) about 15kts ground speed with brakes on. Couple chirps and then the nose really wanted to come down.
Hindsight, leave brakes on would have rolled very little.
Of course totally preventable if I realized what was going on earlier, but sometimes you don't realize these things. Brakes off gives you a few more options.
_______________
Here's a thought for everyone. When Winnipeg was flooding I was flying 6,000lb loads of sandbags from a muddy location to a distant dyke. Picked up load, wheels sank in mud. Trying to rip mains out of ground, I got very very close to dynamic rollover.
Question: Would the wheels have released more easily if the brakes were off?
Concur with Nick, I'll land with brakes off (but toes on the brakes, just in case..) nearly all the time. Also, nose wheel/tail wheel lock in, regardless of whether the brakes are on or off, to give directional stability when the collective is dumped. I've seen a Sea King rotate about 25 degrees, when the tail wheel lock was out, and it's not a pretty sight. Just as important on start up, as well. If it's a pitching or moving deck, or an offshore platform, local requirements come to the fore. Company regs (eg North Sea quoted before), Squadron SOP's, etc will dictate what has been learnt the hard way by others, and saves a lot of relearning. Odd points to consider are deck size and surface; if there's a net made of large diameter rope, you may be advised to leave the brake off, to allow the tyres to roll off the rope and into a hole. Some S76 landings, when the torsion bar between the mains push the other wheel down, need a bit of movement in the wheels which would not be there if the brakes were on.
HFrog, Whirlwinds with brakes. What will they think of next
Matthew, Was your load internal, and if so, wasn't it an option to sling the things? I'll bite, my guess is that the brakes off would allow some rotation of the wheels, thus reducing the suction/stiction of the gear stuck in the mud, thus allowing a better chance of coming out of the gloop.
HFrog, Whirlwinds with brakes. What will they think of next
Matthew, Was your load internal, and if so, wasn't it an option to sling the things? I'll bite, my guess is that the brakes off would allow some rotation of the wheels, thus reducing the suction/stiction of the gear stuck in the mud, thus allowing a better chance of coming out of the gloop.
Last edited by John Eacott; 29th Apr 2002 at 04:52.
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John,
Most of the time the sandbags were external (cargo net) and other things we hauled internal (people, dive gear, zodiacs, dog food for deer stranded on a little island....awwww cute).
I believe it was a full internal load when we got stuck well...turnover time a little slower and the load was a little bigger helped us sink more than usual. We fly faster and end up burning less gas with the internal load so for the longer distances we preferred the internal load.
Most of the time the sandbags were external (cargo net) and other things we hauled internal (people, dive gear, zodiacs, dog food for deer stranded on a little island....awwww cute).
I believe it was a full internal load when we got stuck well...turnover time a little slower and the load was a little bigger helped us sink more than usual. We fly faster and end up burning less gas with the internal load so for the longer distances we preferred the internal load.
Matthew,
OT, but IIRC you are flying the Phrog, have you seen this page? Interesting account from a Marine
OT, but IIRC you are flying the Phrog, have you seen this page? Interesting account from a Marine
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Matt,
I think not, for if you are picking them up out of the mud fighting the suction, whether or not they could rotate (breaks off) or not (Brakes on) wouldn't be a factor IMO.
Just my guess.
I think not, for if you are picking them up out of the mud fighting the suction, whether or not they could rotate (breaks off) or not (Brakes on) wouldn't be a factor IMO.
Just my guess.
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I think that brakes off allows a smoother landing for the pax.
On the S-76 and other wheeled types I have flown, from a steady hover I feel that as the collective is lowered, the mainwheels need to rotate slightly backwards as the aircraft pitches nose down and settles vertically on the ground. If the wheelbrakes are on, all the pitching is done around the mainwheels once they make contact and the nosewheel seems to want to touch harder.
On the S-76 and other wheeled types I have flown, from a steady hover I feel that as the collective is lowered, the mainwheels need to rotate slightly backwards as the aircraft pitches nose down and settles vertically on the ground. If the wheelbrakes are on, all the pitching is done around the mainwheels once they make contact and the nosewheel seems to want to touch harder.
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John, thanks for the link. Some new manoevres I must try. KIDDING. I couldn't believe the video of a quickstop in a H46, which was authorized then, but you don't see us flying like that now. The buttonhook would be good to see at the airshow (if you don't crash at the end), but that would be our only use for it.
I especially like the photo of a formation the same size as Canada's fleet.
(Image found on http://www.f4aviation.co.uk/Oldstuff/h46/h46.htm check that site for all the other pics and good stories.)
I especially like the photo of a formation the same size as Canada's fleet.
(Image found on http://www.f4aviation.co.uk/Oldstuff/h46/h46.htm check that site for all the other pics and good stories.)
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John,
I and my worst englich at werk again.
The video was of a normal quickstop done in an H46, seen on Discovery Channel a few years ago. It amazed me. I read the story of the buttonhook and thought that would be even more so. There is no video of the buttonhook as far as I'm aware.
BTW, the H46 in the video had the brakes off doing the quickstop into a tall grass field....keeping this on topic.
I and my worst englich at werk again.
The video was of a normal quickstop done in an H46, seen on Discovery Channel a few years ago. It amazed me. I read the story of the buttonhook and thought that would be even more so. There is no video of the buttonhook as far as I'm aware.
BTW, the H46 in the video had the brakes off doing the quickstop into a tall grass field....keeping this on topic.
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What about as a safety measure in case of a single engine failure after LDP.
Wouldn't you want to stick at first ground contact.
We are talking about landing sites where there is any room to run it on.
Cheers
Wouldn't you want to stick at first ground contact.
We are talking about landing sites where there is any room to run it on.
Cheers
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Xnr,
If you land with the brakes locked, the result would probably be tire damage (worn flat in a few seconds) and even loss of control (as the wheels skid, perhaps unevenly).
Best to land, get full weight on the wheels, then use the brakes with pumping action.
If you land with the brakes locked, the result would probably be tire damage (worn flat in a few seconds) and even loss of control (as the wheels skid, perhaps unevenly).
Best to land, get full weight on the wheels, then use the brakes with pumping action.
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brakes!
Nick,
Are you saying that the 76 brakes are strong enough to stop that machine" in it's tracks" during a single engine landing to a rig/ helipad.
Or, are the 76 brakes just for " handling" purposes during taxiing/ normal touchdown.
We once missed releasing the brakes and did a slow rolling CAT B landing. Honestly, the brakes did nothing to "dead stop' that aircraft nor did they grab and bang the nosewheel down as everyone thinks will happen.
To be fair, though, maybe the pressure was not at its maximum or we did not set it hard enough.
So, can you tell us if the 76 brakes are
a) for "handling" purposes only or
b) to actually "deadstop" that beast during an OEI CAT A landing.
I've heard arguments for both sides that make sense.
Thanks!
Are you saying that the 76 brakes are strong enough to stop that machine" in it's tracks" during a single engine landing to a rig/ helipad.
Or, are the 76 brakes just for " handling" purposes during taxiing/ normal touchdown.
We once missed releasing the brakes and did a slow rolling CAT B landing. Honestly, the brakes did nothing to "dead stop' that aircraft nor did they grab and bang the nosewheel down as everyone thinks will happen.
To be fair, though, maybe the pressure was not at its maximum or we did not set it hard enough.
So, can you tell us if the 76 brakes are
a) for "handling" purposes only or
b) to actually "deadstop" that beast during an OEI CAT A landing.
I've heard arguments for both sides that make sense.
Thanks!
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donut king,
The brakes in your case were probably not set very hard. It is certainly possible to stop the tire completely while moving forward if you press hard enough, and truly skid the tire. I have left a few dark black streaks to prove that.
With aircraft tires, a few skids is all ittakes to ruin the tire, and a long skid will thin the tire and rupture it.
Landing with the brakes on could also ruin the wheel in some helicopters. One very inexperienced pilot at Sikorsky bent the gear on an S-58 by landing with the brakes on!
In S-76, a smooth hard brake application, without skidding the tire, is assumed in the running landings we do for certification. They are not cosmetic brakes, donut king, they will stop you, and will skid the tire if pressed too hard. Take care to let them cool, or you will warp the disks and the Chief Pilot will have a discussion with you!
Don't expect automobile performance however. Cars have better wheels and brakes, and so they should, so comparivively a car's brake effectiveness is very mch more noticible.
The brakes in your case were probably not set very hard. It is certainly possible to stop the tire completely while moving forward if you press hard enough, and truly skid the tire. I have left a few dark black streaks to prove that.
With aircraft tires, a few skids is all ittakes to ruin the tire, and a long skid will thin the tire and rupture it.
Landing with the brakes on could also ruin the wheel in some helicopters. One very inexperienced pilot at Sikorsky bent the gear on an S-58 by landing with the brakes on!
In S-76, a smooth hard brake application, without skidding the tire, is assumed in the running landings we do for certification. They are not cosmetic brakes, donut king, they will stop you, and will skid the tire if pressed too hard. Take care to let them cool, or you will warp the disks and the Chief Pilot will have a discussion with you!
Don't expect automobile performance however. Cars have better wheels and brakes, and so they should, so comparivively a car's brake effectiveness is very mch more noticible.
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Nick, what if you're landing on an elevated pad, about 70' in diameter (in a 76)? I can understand not setting the brakes if there is some room to roll, but in event of an engine failure just before landing on a small deck there would be absolutely no margin of error concerning brake application. I think having them on is one less thing to worry about.
Most checklists provide about 4 checks before landing to ensure that the brakes or either on or off.(post t/o, cruise, descent and landing checks.)
In a 2 crew aircraft, making a run on landing to run- or taxiway, with the brakes set is more a sign of bad CRM then PDM.
Most checklists provide about 4 checks before landing to ensure that the brakes or either on or off.(post t/o, cruise, descent and landing checks.)
In a 2 crew aircraft, making a run on landing to run- or taxiway, with the brakes set is more a sign of bad CRM then PDM.
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With brakes on, you get some deceleration from the tires, but you also get a nose down pitching moment. With OEI aerodynamic braking is still effective, more effective alone than braking is alone. The two together should give you maximum braking effort, but if you allow the nose to fall too much, then you may be relying only on the less efficient rubber braking or the amount of aft cyclic required to allow aerodynamic braking may get you into aft tip clearance problems.
Whether you have brakes on or off you should fly your profile to zero speed if the pad is small. If you can't do that, then I imagine just putting the mains on and keeping the nose up gives you more braking distance, since you may be able to put the nose over the edge...just don't go too far.
Sudden OEI short final to a pad I'd say overshoot is your best bet 99% of the time. Better to set up the approach you want than accept what you're doing.
Of course, all of the above was not type specific for anything. I fly an H46 where your fuselage attitude is a constant angle to the rotor planes. Thus, nose down is much worse for us...running on low speed with nose slightly up is best.
Whether you have brakes on or off you should fly your profile to zero speed if the pad is small. If you can't do that, then I imagine just putting the mains on and keeping the nose up gives you more braking distance, since you may be able to put the nose over the edge...just don't go too far.
Sudden OEI short final to a pad I'd say overshoot is your best bet 99% of the time. Better to set up the approach you want than accept what you're doing.
Of course, all of the above was not type specific for anything. I fly an H46 where your fuselage attitude is a constant angle to the rotor planes. Thus, nose down is much worse for us...running on low speed with nose slightly up is best.