EC120
EC-120 Overtemp on Startup
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1 - I heard weekend before last (ROB ?) but don't know for sure;
2 - the one I fly before it came to us, last year;
3 - also heard (but haven't seen log book) of another that NAC had for a while - cooked before it came to them though.
How are they working out in Kruger Park ? I hear that the new pilots there really like them and they must be halfway decent to cope with the demands of game work ?
Care to comment, CA ?
2 - the one I fly before it came to us, last year;
3 - also heard (but haven't seen log book) of another that NAC had for a while - cooked before it came to them though.
How are they working out in Kruger Park ? I hear that the new pilots there really like them and they must be halfway decent to cope with the demands of game work ?
Care to comment, CA ?
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I wonder how many 206/as350/ non vemd machines are overtemped and overlooked because of a lack of teltale computer,
maybe the 120 is not easier to cook than any other turbine just easier to be found out when you have!
maybe the 120 is not easier to cook than any other turbine just easier to be found out when you have!
Whatsarunway,
You have just put your finger on one of the important reasons why engines should be monitored. The reduction of hot starts, or over-temping or over-torquing is important to all of us; elimination of these (accidental but not reported events) will reduce the number of engine failures - which are still the cause of about 26% of all accidents.
You have just put your finger on one of the important reasons why engines should be monitored. The reduction of hot starts, or over-temping or over-torquing is important to all of us; elimination of these (accidental but not reported events) will reduce the number of engine failures - which are still the cause of about 26% of all accidents.
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Very valid point. Although most newer Bells have the absolute over temp warning light on the TOT which is not supposed to be able to be reset by the pilot.
(Doesn't stop them colouring it in with a felt tip pen and continuing the two week charter though...)
(Doesn't stop them colouring it in with a felt tip pen and continuing the two week charter though...)
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Whatsarunway, JimL
Excellent points. So do you (or does anyone else) know whether the EC120 has a significantly lower rate of engine failure in practice than the helos without VMED?.
Excellent points. So do you (or does anyone else) know whether the EC120 has a significantly lower rate of engine failure in practice than the helos without VMED?.
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I flew EC120's for SANParks until January this year,mostly gamecapture , but also hot and heavy during surveys. I managed to fly 2300 hrs on type during the 5 years there.
We found the machine well up to the task at lower density altitudes, but tapering off with an increase in altitude. The B206 lobby that make statements of outperforming the EC120 under the same conditions suffer from selective scan during critical phases of flight. The VEMD never lies.
The SANParks engine was overtemped 2 weeks ago, for the first time during 5300hrs of operation. I will post the stats on total RSA reported overtemps here after I get the gen from Turbomeca.
Quick reference guide to hot start a EC 120:
Battery voltage below 17V
Not paying attention
Not resetting throttle completely if you open it up beyond the "Start"line on CP(linkage play)
We found the machine well up to the task at lower density altitudes, but tapering off with an increase in altitude. The B206 lobby that make statements of outperforming the EC120 under the same conditions suffer from selective scan during critical phases of flight. The VEMD never lies.
The SANParks engine was overtemped 2 weeks ago, for the first time during 5300hrs of operation. I will post the stats on total RSA reported overtemps here after I get the gen from Turbomeca.
Quick reference guide to hot start a EC 120:
Battery voltage below 17V
Not paying attention
Not resetting throttle completely if you open it up beyond the "Start"line on CP(linkage play)
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VEMD never lies?
I dont think the 120 can really be compared to the 206 when it comes to usefull load comfort speed and dare i say it , maintenence reliability,
i think the 206 has its advantages though ,
you can put five people into a 206 and be in ballance(maybe with 20 minutes fuel) but if you actually calculate the 120 W+B unless you have kids in the heli, its almost impossible,
althougt the 120 is very relaible, if you have a problem, the customer service from bell is second to none! eurocopter is , eh , not.
Is there any situation where the VEMD can lie, and whose word do you take?
the pilot or the computer?
Thankfully never came up for me but can you imagine trying to argue with the computer?
Also , the 120 only records he last 31 flights and if an overlimit occoured thirty two flights ago, nobody will ever know!
Good system but surely there are some flaws.
I dont think the 120 can really be compared to the 206 when it comes to usefull load comfort speed and dare i say it , maintenence reliability,
i think the 206 has its advantages though ,
you can put five people into a 206 and be in ballance(maybe with 20 minutes fuel) but if you actually calculate the 120 W+B unless you have kids in the heli, its almost impossible,
althougt the 120 is very relaible, if you have a problem, the customer service from bell is second to none! eurocopter is , eh , not.
Is there any situation where the VEMD can lie, and whose word do you take?
the pilot or the computer?
Thankfully never came up for me but can you imagine trying to argue with the computer?
Also , the 120 only records he last 31 flights and if an overlimit occoured thirty two flights ago, nobody will ever know!
Good system but surely there are some flaws.
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Hello everyone,
I though you might be interested how we finally fixed our T45 temp problem:
It was the Confirmation box!!
The bad news is, it was a intermident failure! The "fun" part being the -intermident-!!
You check the damn thing according to the maintenance manual it checks out just fine!
The final tip came from Australia - thanks Frogspawn!!
After a couple of e-mails across the world with some Turbomeca-techs, we eliminated all possible causes. Actually nothing was left!
In Australia there was a similar case so we just gambled on it! Voila!
Also considering the normal prices in this business, the confirmation box is a rather lowprice item!
Thanks again for all the tips!
Frogspawn, your man came up with the right idea!!
3top
I though you might be interested how we finally fixed our T45 temp problem:
It was the Confirmation box!!
The bad news is, it was a intermident failure! The "fun" part being the -intermident-!!
You check the damn thing according to the maintenance manual it checks out just fine!
The final tip came from Australia - thanks Frogspawn!!
After a couple of e-mails across the world with some Turbomeca-techs, we eliminated all possible causes. Actually nothing was left!
In Australia there was a similar case so we just gambled on it! Voila!
Also considering the normal prices in this business, the confirmation box is a rather lowprice item!
Thanks again for all the tips!
Frogspawn, your man came up with the right idea!!
3top
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Hi everyone,
interesting thread!
I only have about 750 hrs in the EC120B but NEVER even got close to a hot start!
Here it goes:
# NEVER even try to start below 17 V!b If you do, you risk a comlete electrical blackout with nothing to shut the throttle - here is one more: Watch these SAFT batteries!! There excellent until they get around 3 years - they show full charge but is just on the screen! With the aux-pump on and starting suddenly everything goes to below 15V in a hurrry!! We exchanged with a kit that uses a new maintenance free Concord....
# Don't worry about the 30 sec of the aux-fuel pump. It only puts pressure into the system until the engine-driven fuel pump takes over. Switch it on, at about 15 sec you crank the temp down, when Ng goes low, go ahead with the start! What if your fuel pressure goes low? The manual says to switch the aux-pump on! Again, no worry about the 30 sec or 60 sec or 300 sec!!
# Now the following WAS in the manual at some time, but I still use it as it works just perfect:
If you have some higher rest T4 showing, start in the shutoff position until Ng has 10%, then roll it into ground idle. You never will overtemp it. (This cools about as good as cranking to Ng10%, but the rest T4 doesn't start to climb again!)
I actually did various hot starts with a rest T4 of around 315°C, NO cooldown cranking, but starting at shutoff until 12% Ng. Sure, you want to watch T4 closely and modulate it accordingly, but I never even got to redline.
Now of course this was trying things out, so normally I crank it down to 230-200°C (but never more than Ng 10% on the cranking...), all while the aux-pump is on. The hotter rest T4 is, the higher you want Ng before rolling to ground idle, BUT never go beyond 14% ( personally I keep the limit at 12%) or you might risk to not light off.
Also on a regular start, be patient until you see the T4 rising a little faster after it passes 300°C. From there on you can push it a little towards the upper limit which will help to accelerate the engine faster ( remember: the hotter you can start the turbine the better - without exceeding limits!!!), and you get off the starter sooner.
On a regular cold start, if you leave the turbine to itself (with the throttle at ground idle) it will take forever to get to Ng 50%.
After T4 starts to go up faster passing 300°C, it will slow down and stop at around 650°C if you don't help it. So as soon as you see T4 rise slowing, start to roll on the throttle slowly. Actually if you are too slow you will reach Ng 50% before T4 ever sees 750°C.
Remember they couldn't make the 120 too good or they put these Squirrels out of business! LOL!!
3top
interesting thread!
I only have about 750 hrs in the EC120B but NEVER even got close to a hot start!
Here it goes:
# NEVER even try to start below 17 V!b If you do, you risk a comlete electrical blackout with nothing to shut the throttle - here is one more: Watch these SAFT batteries!! There excellent until they get around 3 years - they show full charge but is just on the screen! With the aux-pump on and starting suddenly everything goes to below 15V in a hurrry!! We exchanged with a kit that uses a new maintenance free Concord....
# Don't worry about the 30 sec of the aux-fuel pump. It only puts pressure into the system until the engine-driven fuel pump takes over. Switch it on, at about 15 sec you crank the temp down, when Ng goes low, go ahead with the start! What if your fuel pressure goes low? The manual says to switch the aux-pump on! Again, no worry about the 30 sec or 60 sec or 300 sec!!
# Now the following WAS in the manual at some time, but I still use it as it works just perfect:
If you have some higher rest T4 showing, start in the shutoff position until Ng has 10%, then roll it into ground idle. You never will overtemp it. (This cools about as good as cranking to Ng10%, but the rest T4 doesn't start to climb again!)
I actually did various hot starts with a rest T4 of around 315°C, NO cooldown cranking, but starting at shutoff until 12% Ng. Sure, you want to watch T4 closely and modulate it accordingly, but I never even got to redline.
Now of course this was trying things out, so normally I crank it down to 230-200°C (but never more than Ng 10% on the cranking...), all while the aux-pump is on. The hotter rest T4 is, the higher you want Ng before rolling to ground idle, BUT never go beyond 14% ( personally I keep the limit at 12%) or you might risk to not light off.
Also on a regular start, be patient until you see the T4 rising a little faster after it passes 300°C. From there on you can push it a little towards the upper limit which will help to accelerate the engine faster ( remember: the hotter you can start the turbine the better - without exceeding limits!!!), and you get off the starter sooner.
On a regular cold start, if you leave the turbine to itself (with the throttle at ground idle) it will take forever to get to Ng 50%.
After T4 starts to go up faster passing 300°C, it will slow down and stop at around 650°C if you don't help it. So as soon as you see T4 rise slowing, start to roll on the throttle slowly. Actually if you are too slow you will reach Ng 50% before T4 ever sees 750°C.
Remember they couldn't make the 120 too good or they put these Squirrels out of business! LOL!!
3top
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Hi 3top,
Thanks for the gen. I've saved your suggestions to digest slowly. I was shown a similar hot starting procedure by one more experienced pilot but it's not in the manual so the owner would not approve ! Better than a hot start though. Very interesting what you say about the battery life - I will pass this on to the owner.
I undertand that the hot start problems that have been experienced in South Africa recently also relate to the battery dropping during the start and consequently leaving the throttle stuck open - not much that a pilot can do about that. Even pulling the fuel shut off would not be fast enough.
Thanks for the gen. I've saved your suggestions to digest slowly. I was shown a similar hot starting procedure by one more experienced pilot but it's not in the manual so the owner would not approve ! Better than a hot start though. Very interesting what you say about the battery life - I will pass this on to the owner.
I undertand that the hot start problems that have been experienced in South Africa recently also relate to the battery dropping during the start and consequently leaving the throttle stuck open - not much that a pilot can do about that. Even pulling the fuel shut off would not be fast enough.
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I recently had a hotter than normal start on the 120 and although the heater knob was fully closed (it was summer) the P2 flag was displayed on the VEMD. Had it checked out by maint and they adjusted the bleed valve, no problem since.
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Billywizz,
the P2 valve and the switch that brings the "P2" onto the VEMD are 2 different things, side by side. If the valve doesn't close any further you can bet that the valve is closed and probably the microswitch is loose and that is why the "P2" stays.
Best is to observe T4 at a steady state, open and close the Valve, you should have no more than 15°C variation (normally no more than 10°C)
3top
the P2 valve and the switch that brings the "P2" onto the VEMD are 2 different things, side by side. If the valve doesn't close any further you can bet that the valve is closed and probably the microswitch is loose and that is why the "P2" stays.
Best is to observe T4 at a steady state, open and close the Valve, you should have no more than 15°C variation (normally no more than 10°C)
3top
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Hey goaround 7,
one more thing about the battery:
a) It is also NOT in the manual, nevertheless the EC guys from Mexico told us at one of their visits, that is recommended to leave the gen on at all times, even at and/or after shut down! Punch off the BAT but leave the GEN on. Supposedly it has something to do with battery drain through some of the electronics.
b) If you stay overnight or wait all day long for your pax, disconnect the battery. Take off either of the terminals, I normally take off the positive.
c) If you play around in the cockpit without actually starting the ship, use a APU to power the radios and GPS, you won't believe how fast these things suck down the battery. Then you show 22V instead of 25.8V for the start. Botch it a little and your done - it shuts off below 15V
to the "non authorized" Starting Procedure:
As mentioned in my previous post, this procedure WAS in the POH at some time.
Actually it started out without it, then they put this in (Sept.'99), and then they took it out again.
In October 2001 it was still there. Also that you would activate the starter before rolling into the start position. Now you place the throttle in the start position before activating the starter....
My guess is, that some people overdid it with the Ng, and tried to light off at 17% or higher. Most likely you don't start at all. So what you have now is a puddle of fuel somewhere in the turbine.
At the next start up you may or not get a nice long flame shooting out the pipe!
However as you observed, you have a hard time cranking the thing down and still start without a T4 running redline. Besides, this also eats a lot more battery.
In any case run the fuel pump first, it doesn't matter how long it runs - when it is on 18-20 sec, do your cooling crank, and as soon as Ng is low enough for T4 to rise again, go ahead and start.
It is easier to do the "Ng 10% at cut off" thing though.
To EC generally and their frequent changes of procedures:
Just went head on with my boss for going exactly with the manual for Nr adjustment. He claimed the Factory instructions are wrong. I argued, he did the adjustment according to the manual, and guess what, he was right! They wrote it the other way around!
Moral: Your POH is like the bible, mostly it is okay, but some stories I know for a fact are not true!!
This morning I put some new leaves in the Flight Manual (POH), Revision 8a, I think: Section 8 where it explains the button functions of the cyclic and collective:
The new yellow(temporary) leave says "floats" on the floats switch and it says "floats" on the hydraulic off switch, too!
So much for a detailed review BEFORE sending revisions into the field.
I believe the Hot starting procedure is along the same line.
Let's do - ahh better not - or maybe we should after all?
Ask EC WHY they removed the "10% Ng at off position" again?
I would like to know too! Meanwhile I keep using it to keep T4 in check!
note: When I asked the Ec-techs visiting, they couldn't say for what reason the procedure was changed back...
Actually because of this post I observed a couple of temps this morning a little closer:
Cold start: If you don't help T4 after it starts to rise faster after 300°C it will get stuck around 635°C and Ng acceleration will go to near zero.
Repeated 3 hot starts with "my" procedure, hottest with 265°C rest T4. Roll to start after reaching 10% Ng and roll back a little after lightoff. T4 will settle at 740°C everytime before sinking when you help a little to maintain this until Ng reaches 50%.
Ask your owner, whether he prefers a "nearly burned one" every chance or a rather safe "cool" start!
You can perfectly combine both:
Normally if I know I have to start up in short order, I will crank right away after I note down the flight report. This way you took out a lot of heat right away. You still can crank again before starting, while you have the pump on. Just give it a little Ng before rolling into the START position...
3top
goaround 7,
if it helps I can scan the old revision pages that outline the procedure, maybe that helps discussing things with your boss and/or EC. In case your bird is new enough and the Flight Manual never received these changes!
Let me know!
If you want them I need your e-mail.
3top
one more thing about the battery:
a) It is also NOT in the manual, nevertheless the EC guys from Mexico told us at one of their visits, that is recommended to leave the gen on at all times, even at and/or after shut down! Punch off the BAT but leave the GEN on. Supposedly it has something to do with battery drain through some of the electronics.
b) If you stay overnight or wait all day long for your pax, disconnect the battery. Take off either of the terminals, I normally take off the positive.
c) If you play around in the cockpit without actually starting the ship, use a APU to power the radios and GPS, you won't believe how fast these things suck down the battery. Then you show 22V instead of 25.8V for the start. Botch it a little and your done - it shuts off below 15V
to the "non authorized" Starting Procedure:
As mentioned in my previous post, this procedure WAS in the POH at some time.
Actually it started out without it, then they put this in (Sept.'99), and then they took it out again.
In October 2001 it was still there. Also that you would activate the starter before rolling into the start position. Now you place the throttle in the start position before activating the starter....
My guess is, that some people overdid it with the Ng, and tried to light off at 17% or higher. Most likely you don't start at all. So what you have now is a puddle of fuel somewhere in the turbine.
At the next start up you may or not get a nice long flame shooting out the pipe!
However as you observed, you have a hard time cranking the thing down and still start without a T4 running redline. Besides, this also eats a lot more battery.
In any case run the fuel pump first, it doesn't matter how long it runs - when it is on 18-20 sec, do your cooling crank, and as soon as Ng is low enough for T4 to rise again, go ahead and start.
It is easier to do the "Ng 10% at cut off" thing though.
To EC generally and their frequent changes of procedures:
Just went head on with my boss for going exactly with the manual for Nr adjustment. He claimed the Factory instructions are wrong. I argued, he did the adjustment according to the manual, and guess what, he was right! They wrote it the other way around!
Moral: Your POH is like the bible, mostly it is okay, but some stories I know for a fact are not true!!
This morning I put some new leaves in the Flight Manual (POH), Revision 8a, I think: Section 8 where it explains the button functions of the cyclic and collective:
The new yellow(temporary) leave says "floats" on the floats switch and it says "floats" on the hydraulic off switch, too!
So much for a detailed review BEFORE sending revisions into the field.
I believe the Hot starting procedure is along the same line.
Let's do - ahh better not - or maybe we should after all?
Ask EC WHY they removed the "10% Ng at off position" again?
I would like to know too! Meanwhile I keep using it to keep T4 in check!
note: When I asked the Ec-techs visiting, they couldn't say for what reason the procedure was changed back...
Actually because of this post I observed a couple of temps this morning a little closer:
Cold start: If you don't help T4 after it starts to rise faster after 300°C it will get stuck around 635°C and Ng acceleration will go to near zero.
Repeated 3 hot starts with "my" procedure, hottest with 265°C rest T4. Roll to start after reaching 10% Ng and roll back a little after lightoff. T4 will settle at 740°C everytime before sinking when you help a little to maintain this until Ng reaches 50%.
Ask your owner, whether he prefers a "nearly burned one" every chance or a rather safe "cool" start!
You can perfectly combine both:
Normally if I know I have to start up in short order, I will crank right away after I note down the flight report. This way you took out a lot of heat right away. You still can crank again before starting, while you have the pump on. Just give it a little Ng before rolling into the START position...
3top
goaround 7,
if it helps I can scan the old revision pages that outline the procedure, maybe that helps discussing things with your boss and/or EC. In case your bird is new enough and the Flight Manual never received these changes!
Let me know!
If you want them I need your e-mail.
3top
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Twice i've nearly cooked an ec120 engine(on two seperate machines) both times have been due to a faulty FCU.
Just be ready for
hit starter , hear sounds, look at t4 gauge ,nothing, nothing, nothing, nothing, oh my god! followed by a sprained wrist in trying to close the throttle real quick.
1500hrs in the things and every hour wishing i was in a squirell!
Just be ready for
hit starter , hear sounds, look at t4 gauge ,nothing, nothing, nothing, nothing, oh my god! followed by a sprained wrist in trying to close the throttle real quick.
1500hrs in the things and every hour wishing i was in a squirell!
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I agree with 3top, leave the gene on always, I never touch it and was told by our engineers that it has somethink to do with a battery drainage problem.....
Disconnect it when away overnight or when not using the machine.
The pilot and co-pilots map lights are hot wired so be careful not to leave them on.
I have seen guys endorse pilots with the technique of starting by turning the throttle on similar to the 206. I have found that it just don't work right.
I don,t have the latest flight manual at hand but I generaly then direct the pilot to start with the throttle in the detent (or just slightly before is the best position just incase you need a quick shutoff).
the first set of nozzels fire it up well to around 300-350, but the second are a bit slow so you may need to give it a bit.....
As 3top says the turbine preferrs it (around 700) and you save the gene a bit.
With sarting with the throttle as I do you should have no problems even if the battery drops off.
Do you guys judge the health of the battery by the sound of the igniters aswell?.........you can usually pick it every time.
Good luck
Disconnect it when away overnight or when not using the machine.
The pilot and co-pilots map lights are hot wired so be careful not to leave them on.
I have seen guys endorse pilots with the technique of starting by turning the throttle on similar to the 206. I have found that it just don't work right.
I don,t have the latest flight manual at hand but I generaly then direct the pilot to start with the throttle in the detent (or just slightly before is the best position just incase you need a quick shutoff).
the first set of nozzels fire it up well to around 300-350, but the second are a bit slow so you may need to give it a bit.....
As 3top says the turbine preferrs it (around 700) and you save the gene a bit.
With sarting with the throttle as I do you should have no problems even if the battery drops off.
Do you guys judge the health of the battery by the sound of the igniters aswell?.........you can usually pick it every time.
Good luck
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oxi,
I check the battery by how fast it goes down once the starter is engaged. If there is any doubt, that I get the turbine to Ng 50% I cut it, latest at 16V!!! That's your last chance to unlock the throttle.
206 procedure is to much Ng for the Arrius before lighting off.
Though it still is the old procedure, but it works better for me:
Cold start: Engage the starter and roll imediately to ground idle.
Hot start: Engage starter and roll to ground idle at Ng 10%
Charme everytime!
3top
I check the battery by how fast it goes down once the starter is engaged. If there is any doubt, that I get the turbine to Ng 50% I cut it, latest at 16V!!! That's your last chance to unlock the throttle.
206 procedure is to much Ng for the Arrius before lighting off.
Though it still is the old procedure, but it works better for me:
Cold start: Engage the starter and roll imediately to ground idle.
Hot start: Engage starter and roll to ground idle at Ng 10%
Charme everytime!
3top