Agusta A109E brake system
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,598
Received 456 Likes
on
242 Posts
Shawn, it might be possible but I think you'd need to be quite tall and walk quite a lot.
Who told you that - an Agusta salesman?
Who told you that - an Agusta salesman?
I'd heard about that too, we tried it once at an engineering base, engineer spinning the blades from the front where he could reach them, I watched the EDU we got a flicker on the hydraulic pressure gauges and got bored after about 5 revolutions.
If it does work I guess you'd need patience.
If it does work I guess you'd need patience.
Originally Posted by Dick Smith
Can anyone advise if you pump on the foot brakes without the rotor going, if it does anything? That is, will it stop the machine?
The toe brake controls are really actuator controls for the brake valves: if there is no pressure in the hyd system, they are inoperative.
I've been reading the 109S training notes (essentially the same hydraulic system as the 109E), and in every hyd diagram for the brakes and the nosewheel lock the notes show an emergency pressure line input. There is no narrative (that I can find) as to how that emergency pressure is used for the brakes or NW lock!
Using the schematic on page 3 of 29-21-3M it appears that the emergency pressure line routes via the landing gear selector valve into the triplex selector valve, but it seems to go through the landing gear selector valve first. My interpretation is that this would only give pressure from the emergency accumulator to the brakes & nosewheel in the event that the U/C lever is then moved to the emergency down after selecting the emergency system.
I suppose that you could try changing the Emergency Selector (under the landing gear lever) from Normal to Emerg when the brake pressure is zero, and see if it then charges the parking brake, but I am dubious as to how it would route through the landing gear valve. As to whether the emergency accumulator will hold its pressure any better than the normal accumulator, I don't know, but if it works, it may give you brakes to hold the machine until engine start and recharge of both hyd systems
The schematic is downloadable as a full size jpg here, or as a pdf here.
There is no reference (that I can find) as to how that emergency pressure is used for the brakes or NW lock!
If you select the landing gear handle to the emergency down position you will enable the parking brake and nosewheel lock through the emergency hyd system. This only enables the nosewheel lock and the parking brake...it does not give you toe brakes. The idea is that you'll still be able to stop following an emergency gear extension using the parking brake handle. Moving the landing gear locking lever to emergency doesn't do anything except allow the gear lever to be lowered to the emergency down position.
The emergency system DOES keep its charge pretty well, but putting the gear handle down just for brakes is at best an emergency procedure. Put the handle in emergency down and you must undergo maintenance action before resetting. Also, this will only work if you've left the accumulators pressurized...if you've dumped the accumulators (pre flight to check hyd rsvr levels) then no ammount of moving gear handle or park brake lever will help.
Hope all's well down there.
All the best,
HeloPat
A-109 brake
If it is any comfort to you - I used to work on Airbus 320 jet and if left on the apron with park brake engaged, its park brake accumulator pressure was depleted in about 6 - 8 hours... So 109E is not the only one with this problem... Chock it ALLWAYS even if it is level, as machine might move under some extreme downwash from (big) helicopter landing nearby.
I am aware of one incident where an EMS (A-109K2) helicopter landed on the (inclined) road, attending a road traffic accident, and one brake released, went unnoticed, so helicopter went off road and rolled over..
(Same EMS operator lost another K2 skids equipped, when it skidded (skied?) downhill on a ski piste.)
Now I work on A-109E too and can only confirm that breaking safetywire and moving Emergency lever only allows you to move LDGear handle to EMER position, thus releasing pressure (if there is any) from emergency utility accumulator to PARK brake ONLY! (no toe brakes!!) And this requires maintenance action, so you can use it only to prevent something bad to happen.
To release pressure from accumulators to see the correct level in Hyd sys 2 reservoir, you have to open the little door under the nose on the right side (no tools needed) and push one after the other two buttons (one accumulator each) and keep them pushed until hissing stops with a distinguished click) Correct level is marked on the rim of the glass - not on the sightglass itself!!
Another tricky thing is oil level in transmission (not on all A-109E-depends on PN, SN) Make sure you do the correct procedure for your SN, otherwise you might easily end up with not enough oil in the system ( low TXMSN oil press caption might flicker) or overfilling it. In our case you must check level five min. after shutdown after rotor RPM decayed naturally and oil level shall be ABOVE MAX marking (max 5 mm above) in TXMSN sightglass with nearly empty in CGB sightglass (below MIN marking).
Regards,
hoistop
I am aware of one incident where an EMS (A-109K2) helicopter landed on the (inclined) road, attending a road traffic accident, and one brake released, went unnoticed, so helicopter went off road and rolled over..
(Same EMS operator lost another K2 skids equipped, when it skidded (skied?) downhill on a ski piste.)
Now I work on A-109E too and can only confirm that breaking safetywire and moving Emergency lever only allows you to move LDGear handle to EMER position, thus releasing pressure (if there is any) from emergency utility accumulator to PARK brake ONLY! (no toe brakes!!) And this requires maintenance action, so you can use it only to prevent something bad to happen.
To release pressure from accumulators to see the correct level in Hyd sys 2 reservoir, you have to open the little door under the nose on the right side (no tools needed) and push one after the other two buttons (one accumulator each) and keep them pushed until hissing stops with a distinguished click) Correct level is marked on the rim of the glass - not on the sightglass itself!!
Another tricky thing is oil level in transmission (not on all A-109E-depends on PN, SN) Make sure you do the correct procedure for your SN, otherwise you might easily end up with not enough oil in the system ( low TXMSN oil press caption might flicker) or overfilling it. In our case you must check level five min. after shutdown after rotor RPM decayed naturally and oil level shall be ABOVE MAX marking (max 5 mm above) in TXMSN sightglass with nearly empty in CGB sightglass (below MIN marking).
Regards,
hoistop
Makes an interesting comparison with a 365 equipped with power brakes.
This has an external pushbutton switch on the rh side of the nose that allows the brakes to recharged by the emergency electric pump without entering the cockpit.
However even this might not save you.
We had a pilot leave an aircraft for several days who failed to check that there was still brake pressure before pulling out the chocks.
Passers by were treated to the sight of a very tall pilot bent almost double trying to open a side panel and operate the switch while the aircraft was rolling away.
Aircraft fine ego badly bruised!!!!!
I just wonder how on earth this system got certified in the A109. I estimate that the weight of the 365 emergency pump is about 3 pounds plus say another 3 for piping.
It uses the LH main system for fluid supply. They must have really been scraping the weight saving barrel not to add a small pump for topping up the brakes on the 109. Maybe a mod is called for.
This has an external pushbutton switch on the rh side of the nose that allows the brakes to recharged by the emergency electric pump without entering the cockpit.
However even this might not save you.
We had a pilot leave an aircraft for several days who failed to check that there was still brake pressure before pulling out the chocks.
Passers by were treated to the sight of a very tall pilot bent almost double trying to open a side panel and operate the switch while the aircraft was rolling away.
Aircraft fine ego badly bruised!!!!!
I just wonder how on earth this system got certified in the A109. I estimate that the weight of the 365 emergency pump is about 3 pounds plus say another 3 for piping.
It uses the LH main system for fluid supply. They must have really been scraping the weight saving barrel not to add a small pump for topping up the brakes on the 109. Maybe a mod is called for.
Last edited by ericferret; 15th Feb 2009 at 11:18.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,598
Received 456 Likes
on
242 Posts
My rule of thumb is NEVER to pull the chocks away on a hard surface. Try to remove them only gently. If they need a pull the wheel is leaning on them....nuff said
Join Date: Apr 2008
Location: miami
Age: 54
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
The procedure of moving that switch to emergency and throwing down the gear handle into the emergency position to set the parking brake was applied more than once in the US Coast Guard versions of the A109E, and thank goodness it works. The aircraft were landing on a pitching and rolling ship deck and the accumulators weren't getting charged due to a bad switch (details are kinda fuzzy on that, sorry, but corrosion issues led to some weird electrical issues while underway). The pitching up of the ship wasn't nearly as bad as the sudden pitching down and the slow roll towards the hangar. With regard to the electrical pump, we had the ability to activate such a thing without the rotors turning that would charge up the brake accumulators, but it was never shown in the system diagrams, why I can't answer. The CG has terminated that lease, so I know of at least 8 A109E's with that system on them, unless they took them out upon return to the factory.
Join Date: Jul 2002
Location: Downwind
Posts: 348
Likes: 0
Received 0 Likes
on
0 Posts
I have to say I thought this might have been Dick taking the mickey.
I'm amazed to find it's a genuine nightmare.
My unreserved apologies and my unrestrained disbelief that this hasn't been fixed in the 30+ years the fault has been out there.....
Even old FIATs had a better setup.
I'm amazed to find it's a genuine nightmare.
My unreserved apologies and my unrestrained disbelief that this hasn't been fixed in the 30+ years the fault has been out there.....
Even old FIATs had a better setup.
I was taught to chock the aircraft and then release the brakes if parking for a long period. On your return, and just before departure, reapply the brakes (the pressure is still in the accumulator) and remove the chock.
FNW
FNW
Join Date: Dec 2009
Location: Portugal
Age: 45
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
RULE's OF THUMB in A109E:
The HYD systems in A109 are:
#1 HYD System
- cyclic, collective and pedals
#2 HYD System
- cyclic, collective
UTILITY HYD SYSTEM
- Normal System: parking break, toe brake, rotor brake, landing gear retraction/extraction and nose wheel center lock.
- Emergency System: landing gear extraction, parking break & nose wheel center lock.
If you want to power the HYD systems of the A109E you have to start the engines in order to have the transmission working. Why?? Because the pumps of the diferent systems are MECHANICALLY driven by the main transmission! So if you the rotor rotating you have HYD power!
If you dont have the transmission working you dont have any HYD power! Watch Out! The chucks/socks are your friend, use it!
In the A109E despite the WIRED Emergency selector is in the Landing Gear pedestal, it powers not only the Landing Gear Extraction, but also the parking break and the nose wheel center lock!
If you press the 2 buttons near the front avionics bay you will deplet the emergency accumulator and will be without any emergency pressure (but only on ground because in flight you cannot press them)!!!
Bye!
I am an A109E (co)pilot! (HEMS in Portugal)!
The HYD systems in A109 are:
#1 HYD System
- cyclic, collective and pedals
#2 HYD System
- cyclic, collective
UTILITY HYD SYSTEM
- Normal System: parking break, toe brake, rotor brake, landing gear retraction/extraction and nose wheel center lock.
- Emergency System: landing gear extraction, parking break & nose wheel center lock.
If you want to power the HYD systems of the A109E you have to start the engines in order to have the transmission working. Why?? Because the pumps of the diferent systems are MECHANICALLY driven by the main transmission! So if you the rotor rotating you have HYD power!
If you dont have the transmission working you dont have any HYD power! Watch Out! The chucks/socks are your friend, use it!
In the A109E despite the WIRED Emergency selector is in the Landing Gear pedestal, it powers not only the Landing Gear Extraction, but also the parking break and the nose wheel center lock!
If you press the 2 buttons near the front avionics bay you will deplet the emergency accumulator and will be without any emergency pressure (but only on ground because in flight you cannot press them)!!!
Bye!
I am an A109E (co)pilot! (HEMS in Portugal)!
Join Date: Dec 2009
Location: Portugal
Age: 45
Posts: 12
Likes: 0
Received 0 Likes
on
0 Posts
In a A109E that will never happen because if want to have access to the pressure inside those accumulators you have to break the gold wire and put the landing gear in emerg!
