EC135
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Educated guess at an empty weight of 1860kg, calculated from SPIFR with other (but similar weight) kit in place of left seat PFD/ND screens & second sticks.
What's a winch & floats? Say 140kg?, plus 200kg for pilots & kit - so 2200 for cash ZFW. 1:30 to 1:45 endurance from arrival at first winch job, if Droopy's calculations are OK'd by CAA!
What's a winch & floats? Say 140kg?, plus 200kg for pilots & kit - so 2200 for cash ZFW. 1:30 to 1:45 endurance from arrival at first winch job, if Droopy's calculations are OK'd by CAA!
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Description of Autotrim in EC-135
Can someone please pm me to discuss how the autotrim in the EC-135 works?
Either that or point me to somewhere that describes how it works?
Either that or point me to somewhere that describes how it works?
Sent to PM
My read.................A/TRIM
It trims the cyclic. Unlike older autopilots which just referenced themselves via the actuators against the force trim brakes until the actuators saturated (ran out of movement) the APM 2000 will reposition the cyclic via the Trim Actuators (which have an RVDT inside to tell the AP where they are.
)
The Trim Actuators (parallel actuator) when in SAS/AP-SAS will re-trim the cyclic via the 4 way beep switch or release while centreing the EHA's and SEMA's when you push the FTR. When in UPPER modes of the AP the 4 way trim will change the coupled modes, L/R for HEADING, Fore/Aft (Up/Down?) for ALT, IAS, V/S as appropriate and the AP will re-trim as/if required. The A/TRIM warning serves also to tell you that there is something amiss with the upper modes and the AP is not AP - ing and you should fly it hands on.
It is not very noticeable. Most prevalent trim movement is if you couple ALT and change a big chunk of power. You will see the cyclic move. GA will make it move a fair bit as well depending on software and speed at the time.
The AP in the 135 is a bit of a mess in some ways. The SEMA's (series actuator) were installed because the EHA's (yet another series actuator) are prone to drifting over time. So you have the "basic" SAS with analog computer and EHA's then Autopilot over the top also doing SAS at a better job with EHA's with analog SAS as redundancy and then Autopilot UPPER modes with SEMA's.
SEMA - Smart Electro Mechanical Actuator
EHA - Electro Hydraulic Actuator
When you "decouple" the cyclic is always in a "trimmed" position. Saves you having to keep an eye on the "galvanometers" to see if they are reaching the stops and having to centre them by pushing the FT release.
The YAW "trim" is indicated on the PFD. Push the corresponding pedal! Takes a while to get used to as the aircraft flies left hand down and about half a ball out of trim in the cruise. Thats why your STBY AH is in the panel on a funny angle!
P.S. WTF is a BACON Relay?
It trims the cyclic. Unlike older autopilots which just referenced themselves via the actuators against the force trim brakes until the actuators saturated (ran out of movement) the APM 2000 will reposition the cyclic via the Trim Actuators (which have an RVDT inside to tell the AP where they are.
)The Trim Actuators (parallel actuator) when in SAS/AP-SAS will re-trim the cyclic via the 4 way beep switch or release while centreing the EHA's and SEMA's when you push the FTR. When in UPPER modes of the AP the 4 way trim will change the coupled modes, L/R for HEADING, Fore/Aft (Up/Down?) for ALT, IAS, V/S as appropriate and the AP will re-trim as/if required. The A/TRIM warning serves also to tell you that there is something amiss with the upper modes and the AP is not AP - ing and you should fly it hands on.
It is not very noticeable. Most prevalent trim movement is if you couple ALT and change a big chunk of power. You will see the cyclic move. GA will make it move a fair bit as well depending on software and speed at the time.
The AP in the 135 is a bit of a mess in some ways. The SEMA's (series actuator) were installed because the EHA's (yet another series actuator) are prone to drifting over time. So you have the "basic" SAS with analog computer and EHA's then Autopilot over the top also doing SAS at a better job with EHA's with analog SAS as redundancy and then Autopilot UPPER modes with SEMA's.
SEMA - Smart Electro Mechanical Actuator
EHA - Electro Hydraulic Actuator
When you "decouple" the cyclic is always in a "trimmed" position. Saves you having to keep an eye on the "galvanometers" to see if they are reaching the stops and having to centre them by pushing the FT release.
The YAW "trim" is indicated on the PFD. Push the corresponding pedal! Takes a while to get used to as the aircraft flies left hand down and about half a ball out of trim in the cruise. Thats why your STBY AH is in the panel on a funny angle!
P.S. WTF is a BACON Relay?
Last edited by RVDT; 10th Jan 2009 at 03:47.
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P.S. WTF is a BACON Relay?
You know... the thing you sit on.
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Thanks for the info on autotrim. From what I can gather it only works if the attitude mode and autopilot is engaged? Is that correct?
What happens in the cruise if the pilot pushes and holds the stick away from the initial 'trim' posiition?
What happens in the cruise if the pilot pushes and holds the stick away from the initial 'trim' posiition?
Shawn, yes to the first question. To the second:- at speed it acts just like any other system in that the attitude and cyclic will return to datum as long as the trim release or beep trim have not been used. Below 40kt however the datum effectively follows cyclic displacement without you having to re-trim. It is however 18 months since I was current so would stand corrected.
Shawn,
1st - As long as the autopilot is ON you are in ATT mode. OFF you are in analog SAS. The A/TRIM switch and the light within and WARNING indication are to advise of a problem within the A/P.
2nd - If you push the stick it will NOT automatically trim. Let go of the stick and it will go back to the previous attitude. If you push the stick and press FTR or TRIM via the 4 way switch it will trim accordingly. In UPPER mode if you OVERRIDE ALT,IAS,GA,V/S,ALT.A,G/S or LOC you will get a warning indication on the PFD caption for the respective mode.
Now there are a few pitfalls, Google G-SPAU and G-IWRC accidents.
One thing I am not so sure of is the removal of the GONG and warning indication with A/P DECOUPLE in the latest software version. It served 2 purposes, it let you know if the A/P decoupled intentionally or NOT!
The issue with G-SPAU has been addressed in later software as the bug does not default to "N" any longer on startup.
A small point but the "HEADING" control should be on the ICP with a knob to turn it and push the knob to centre it. Same as the COURSE button. The AP controller should just have an engage pushbutton for heading - a la A109.
As I said before the AP on the 135 is a bit of a kludge.
Too many little things to be effected by heat, vibration etc etc..................
Although it is getting better slowly.
Bladecrack - the squint in the FCDS is in the AHRU!
1st - As long as the autopilot is ON you are in ATT mode. OFF you are in analog SAS. The A/TRIM switch and the light within and WARNING indication are to advise of a problem within the A/P.
2nd - If you push the stick it will NOT automatically trim. Let go of the stick and it will go back to the previous attitude. If you push the stick and press FTR or TRIM via the 4 way switch it will trim accordingly. In UPPER mode if you OVERRIDE ALT,IAS,GA,V/S,ALT.A,G/S or LOC you will get a warning indication on the PFD caption for the respective mode.
Now there are a few pitfalls, Google G-SPAU and G-IWRC accidents.
One thing I am not so sure of is the removal of the GONG and warning indication with A/P DECOUPLE in the latest software version. It served 2 purposes, it let you know if the A/P decoupled intentionally or NOT!
The issue with G-SPAU has been addressed in later software as the bug does not default to "N" any longer on startup.
A small point but the "HEADING" control should be on the ICP with a knob to turn it and push the knob to centre it. Same as the COURSE button. The AP controller should just have an engage pushbutton for heading - a la A109.
As I said before the AP on the 135 is a bit of a kludge.
Wikipedia - A kludge (alternately, kluge[1]) is a clumsy or inelegant solution to a problem or difficulty. In engineering, a kludge is a workaround, typically using unrelated parts cobbled together. Especially in computer programs, a kludge is often used to fix an unanticipated problem in an earlier kludge; this is essentially a kind of cruft. A kludge is an ad hoc engineering solution, inelegant in principle but possibly elegantly pragmatic, from klug [german] meaning clever.
Although it is getting better slowly.
Bladecrack - the squint in the FCDS is in the AHRU!
Shawn,
I'm sure RVDT will correct me if I'm wrong, but making the assumption the EC-155 and EC-135 systems are essentially similar when in basic ATT mode (ignoring Upper Mode engagement) I think you are possibly misinterpreting the meaning of Auto Trim. The Auto Trim basically means the AP is operating in Attitude mode, and that Auto-trimming will take place to ensure continuous series actuator (SEMA) centralisation, and control movement to maintain Attitude datums - particularly noticeable with the heading holding (not HDG Hold.)
There are two basic modes of operation - Follow up trim, which ECF call 'Tactical Mode' and a conventional mode, which ECF call 'cruise mode.'
The follow up trim operates below 40 KIAS, and allows the pilot to push against the cyclic and the AP will re-datum to the new attitude. There is obviously hysteresis built into the transition, such that on departure the AP will have reverted to cruise mode BY 40 KIAS, and on deceleration the AP starts to transition back to 'Tac' mode at 40 KIAS and has fully reverted BY 30 KIAS, to give a seamless feel to the pilot. In 'Tac' mode it's a bit like the SFENA system found on some Bell 212s.
In 'tac' mode the AP respects heading hold at all times (if the pedal micro-switches are released) whereas in cruise mode it is roll dependant, and varies between heading hold and turn co-ordination. In cruise mode the cyclic behaves as with any other ATT system, when displaced.
The Cyclic and Yaw Auto Trim functions can be de-selected independantly using the APMS (Auto Pilot Mode Select) panel, which could be quite useful in the event of a trim runwaway - the pilot can retain the remaining AP functions whilst deselecting the relevant channel. (By comparison, if I have a yaw trim problem in the S-92 and deselect it, the whol AFCS goes into SAS mode and I have no coupled functions at all. In the 155, I could take out Yaw A.Trim and keep ALT, IAS and NAV coupling and just use my feet to keep trimmed in yaw. Anyway, don't get me started.....)
With the 155, the transition during the departure is programed to not only adopt cruise mode, but to alter the nose down attitude to that required for a Vy climb - so the pilot sets 10 degrees nose down in the hover, the AP trims to that datum, the aircraft accelerates and as it passes 40 KIAS the nose starts to rise and adopts an 80 KIAS climb attitude. I understand it's part of an intention ECF had for a fully automated Cat A take off. Still requires a bit of cyclic beep in roll, though, otherwise you end up in a climbing turn!
I sincerely hope that this is not 'duff gen' in relation to the 135, and should it prove so I will delete the relevant portions- the limited 135 info I have, though, (conversion notes from a large UK onshore operator) suggests the systems are near identical.
I'm sure RVDT will correct me if I'm wrong, but making the assumption the EC-155 and EC-135 systems are essentially similar when in basic ATT mode (ignoring Upper Mode engagement) I think you are possibly misinterpreting the meaning of Auto Trim. The Auto Trim basically means the AP is operating in Attitude mode, and that Auto-trimming will take place to ensure continuous series actuator (SEMA) centralisation, and control movement to maintain Attitude datums - particularly noticeable with the heading holding (not HDG Hold.)
There are two basic modes of operation - Follow up trim, which ECF call 'Tactical Mode' and a conventional mode, which ECF call 'cruise mode.'
The follow up trim operates below 40 KIAS, and allows the pilot to push against the cyclic and the AP will re-datum to the new attitude. There is obviously hysteresis built into the transition, such that on departure the AP will have reverted to cruise mode BY 40 KIAS, and on deceleration the AP starts to transition back to 'Tac' mode at 40 KIAS and has fully reverted BY 30 KIAS, to give a seamless feel to the pilot. In 'Tac' mode it's a bit like the SFENA system found on some Bell 212s.
In 'tac' mode the AP respects heading hold at all times (if the pedal micro-switches are released) whereas in cruise mode it is roll dependant, and varies between heading hold and turn co-ordination. In cruise mode the cyclic behaves as with any other ATT system, when displaced.
The Cyclic and Yaw Auto Trim functions can be de-selected independantly using the APMS (Auto Pilot Mode Select) panel, which could be quite useful in the event of a trim runwaway - the pilot can retain the remaining AP functions whilst deselecting the relevant channel. (By comparison, if I have a yaw trim problem in the S-92 and deselect it, the whol AFCS goes into SAS mode and I have no coupled functions at all. In the 155, I could take out Yaw A.Trim and keep ALT, IAS and NAV coupling and just use my feet to keep trimmed in yaw. Anyway, don't get me started.....)
With the 155, the transition during the departure is programed to not only adopt cruise mode, but to alter the nose down attitude to that required for a Vy climb - so the pilot sets 10 degrees nose down in the hover, the AP trims to that datum, the aircraft accelerates and as it passes 40 KIAS the nose starts to rise and adopts an 80 KIAS climb attitude. I understand it's part of an intention ECF had for a fully automated Cat A take off. Still requires a bit of cyclic beep in roll, though, otherwise you end up in a climbing turn!
I sincerely hope that this is not 'duff gen' in relation to the 135, and should it prove so I will delete the relevant portions- the limited 135 info I have, though, (conversion notes from a large UK onshore operator) suggests the systems are near identical.
Well flog me with a warm lettuce...................... (P.Keating one time Prime Minister of Australia.)
As 212 man sez.......................
The 135 does Auto Trim (follow up) below 40 knots. Just tried it. It is not very fast but works fine.
The RFM Supplement doesn't mention it and it is not in the AMM Systems Description. Although I am sure it is in the MM for the AP.
There is evidently an APM 2000 Pilot's Manual for the EC135. Never seen one and it does mention in the RFM Supplement that "Section 4.2 Operation - The sequence of AFCS mode shown within is not mandatory."
As 212 man sez.......................
The 135 does Auto Trim (follow up) below 40 knots. Just tried it. It is not very fast but works fine.
The RFM Supplement doesn't mention it and it is not in the AMM Systems Description. Although I am sure it is in the MM for the AP.
There is evidently an APM 2000 Pilot's Manual for the EC135. Never seen one and it does mention in the RFM Supplement that "Section 4.2 Operation - The sequence of AFCS mode shown within is not mandatory."
You might want to go back to your TRTO and suggest they expand the detail in their briefings and ground school notes! It's a pretty fundamental aspect of the aircraft's handling
In the USA? What's a type rating?
Was pretty much skimmed over on the frame course in Donauworth as well.
I will enquire with SAGEM on getting an APM 2000 Operators manual and find out whether it is "approved" documentation.
Was pretty much skimmed over on the frame course in Donauworth as well.
I will enquire with SAGEM on getting an APM 2000 Operators manual and find out whether it is "approved" documentation.
RVDT, I don't think you will find an operator's manual, as the functionality is installation specific. There is, however, a CMM ( Componant Maintenance Manual) which should be part of the maintenance manual CD that comes with the aircraft. Also, the SDS should add some meat.
Shawn, 212 man,
I have put in a request to SAGEM and going on past experience should have a reply within 6 months.
212,
I have dredged the SDS and it is very vague about the A/TRIM function. It is referred to variously between Attitude Trim and Automatic Trim depending on which document you are reading. No mention of the change in mode with speed as quoted by 212 man although it is there. I think it is a case of "who knew?"
As there is nothing in the published documentation that is required to operate and maintain the thing, how would you?
There is no Chapter 22 in the EC135 ECMM. There is an SDS description in the AMM but is very vague and I can't find anything about it.
The RFM Supplement 9.2-48 OPERATION 4.2.2 Takeoff and Climbout
NOTE: If unsymmetrical stick forces occur during hover, press FTR switch briefly.
This is the way I have been operating it for ~250 hours.
Might drop a line to my maulwürfe in ECD.
I have put in a request to SAGEM and going on past experience should have a reply within 6 months.
212,
I have dredged the SDS and it is very vague about the A/TRIM function. It is referred to variously between Attitude Trim and Automatic Trim depending on which document you are reading. No mention of the change in mode with speed as quoted by 212 man although it is there. I think it is a case of "who knew?"
As there is nothing in the published documentation that is required to operate and maintain the thing, how would you?
There is no Chapter 22 in the EC135 ECMM. There is an SDS description in the AMM but is very vague and I can't find anything about it.
The RFM Supplement 9.2-48 OPERATION 4.2.2 Takeoff and Climbout
NOTE: If unsymmetrical stick forces occur during hover, press FTR switch briefly.
This is the way I have been operating it for ~250 hours.
Might drop a line to my maulwürfe in ECD.
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Quick Question: If i want to fly the aircraft without anycyclic augmentation system of follow trim...basically the same as with the FTR permanently depressed, what cb do i pull and is there any rule against it?...for instructional reasons before you ask!!
i.e You mean if the FTR switch was stuck "closed".
You cannot simulate this as the clutches require electrical power to open. If the switch was stuck closed which is highly unlikely as there are two sets of contacts both of which would have to be stuck.
Hardly a difficult situation. Like flying a B206 - yawn.
"If" it did happen - Pull CB "ATT TRIM REL" Overhead panel 12VE Breaker 7CC 1 Amp driven off PP10E Bus.
Is it illegal - most probably.
You cannot simulate this as the clutches require electrical power to open. If the switch was stuck closed which is highly unlikely as there are two sets of contacts both of which would have to be stuck.
Hardly a difficult situation. Like flying a B206 - yawn.
"If" it did happen - Pull CB "ATT TRIM REL" Overhead panel 12VE Breaker 7CC 1 Amp driven off PP10E Bus.
Is it illegal - most probably.