Powerchecks...
Thread Starter
Powerchecks...
Hi,
1 How do you do the power checks?
A) light on the skis?
B) hovering if necessary, to be near the limits?
I know the procedure but I would like to know if anyone thinks that it's better to do it near the OEI limits.
EDITED: I'm thinking in the 412 but it isn't a specific question.
Thanks.
Aser
1 How do you do the power checks?
A) light on the skis?
B) hovering if necessary, to be near the limits?
I know the procedure but I would like to know if anyone thinks that it's better to do it near the OEI limits.
EDITED: I'm thinking in the 412 but it isn't a specific question.
Thanks.
Aser
Last edited by Aser; 9th Oct 2005 at 19:20.
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Apologies for any errors, but this may help for 412:
Done below limits (at 55% Eng Tq) and then checked against graph. Although, I think its acceptable to pull to limit (N1/ITT) and record everything else. May become a problem if you are at busy area, and climbing rapidly
Edited: Presumably you mean PACs?
Done below limits (at 55% Eng Tq) and then checked against graph. Although, I think its acceptable to pull to limit (N1/ITT) and record everything else. May become a problem if you are at busy area, and climbing rapidly
Edited: Presumably you mean PACs?
Power Trend Checks, Topping Checks, Power Availability Checks?
The RFM for the 412 has a procedure for doing Power Assurance Checks...the maintenance manual has the procedure for the topping checks...there are several field expedient checks for determining power actually available for pinnacle landings, etc.....which one you looking for?
Aser.....mighty nice Co-Pilot you had with you at Heli-Tech...way too nice for you!
The RFM for the 412 has a procedure for doing Power Assurance Checks...the maintenance manual has the procedure for the topping checks...there are several field expedient checks for determining power actually available for pinnacle landings, etc.....which one you looking for?
Aser.....mighty nice Co-Pilot you had with you at Heli-Tech...way too nice for you!
Thread Starter
I mean Power Assurance Checks.
I've seen pilots doing it just getting the heli light on the skis then write everything , but another said he prefer to do it by pulling just NEAR the limits , but not reaching it.
I just wanted to hear more comments.
How often is a topping check done?
Sasless: I know the RFM but what do you mean with "field expedient checks"
Thanks for the comments on the co-pilot , I will post some pics on the huey thread.
Best regards.
Aser
I've seen pilots doing it just getting the heli light on the skis then write everything , but another said he prefer to do it by pulling just NEAR the limits , but not reaching it.
I just wanted to hear more comments.
How often is a topping check done?
Sasless: I know the RFM but what do you mean with "field expedient checks"
Thanks for the comments on the co-pilot , I will post some pics on the huey thread.
Best regards.
Aser
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The Power Assurance Check is used to track the trend of an engine over time and requires you to apply power until the target Q, based on the current temp and PA, is achieved (OEI) . Usually you will be light on the skids because the target Q is in the region of 40-50% but you can also do this in flight (I don't recommend it though). The AFM describes the procedure clearly and also says that you should do a PAC daily. We do them every 25 hours.
The engine topping check requires you to fly OEI and pull power until a limit is reached (Q, N1, or ITT, whichever comes first). Should be done when an engine or engine component has been changed (governor, etc...). I always do them on contract when I take over a machine to ensure that, when I need it, full OEI power will be available.
The engine topping check requires you to fly OEI and pull power until a limit is reached (Q, N1, or ITT, whichever comes first). Should be done when an engine or engine component has been changed (governor, etc...). I always do them on contract when I take over a machine to ensure that, when I need it, full OEI power will be available.
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PAC in our B430 is whilst on the ground, pull 93% N1 AND min Q of 50%.
Definately light on the wheels at this point and thinks about getting airbourne on windy days and when not much gas in the tank.
Hence PF always on the controls while the PNF jots the numbers.
Every 10 hrs per our maintenence ops.
Definately light on the wheels at this point and thinks about getting airbourne on windy days and when not much gas in the tank.
Hence PF always on the controls while the PNF jots the numbers.
Every 10 hrs per our maintenence ops.
412 PAC - best done at 55% Tq - puts the ITT into the expanded scale (>700deg) and is therefore more accurate. We no longer top out the engines (as was done on the 212) but insert a part-power stop. If, with that fitted, the N1 reads 92 - 92.8 when the Nr droops, the engine power is as it should be (Bell says).
Thread Starter
oldbeefer: could you explain how works the "part-power stop" ?
Thanks.
Thanks.
but insert a part-power stop. If, with that fitted, the N1 reads 92 - 92.8 when the Nr droops, the engine power is as it should be (Bell says).
Aser,
little bit rusty on 212/412 AFCUs now, but as I recall, the topping adjustment is accomplished by moving a cam on the AFCU assembly, which then determines how far a mechanical arm attached to the throttle can move. To carry out topping checks without the need to get airborne, and to conserve engine life, it is possible to insert a bush of sorts (the part power stop) to this cam assembly, that limits the movement of the arm even further. The theory is that if you can achieve 92-92.8% g with this 'obstruction' in place, with it removed you should be able to achieve the normal topping figures (102.4 etc depending on the engine series).
In effect, this achieves much the same result as the means by which OEI training is carried out; a throttle is backed off to reduce the topping value and then frictioned tightly to prevent inadvertent movement while the other throttle is then used for simulating failures.
little bit rusty on 212/412 AFCUs now, but as I recall, the topping adjustment is accomplished by moving a cam on the AFCU assembly, which then determines how far a mechanical arm attached to the throttle can move. To carry out topping checks without the need to get airborne, and to conserve engine life, it is possible to insert a bush of sorts (the part power stop) to this cam assembly, that limits the movement of the arm even further. The theory is that if you can achieve 92-92.8% g with this 'obstruction' in place, with it removed you should be able to achieve the normal topping figures (102.4 etc depending on the engine series).
In effect, this achieves much the same result as the means by which OEI training is carried out; a throttle is backed off to reduce the topping value and then frictioned tightly to prevent inadvertent movement while the other throttle is then used for simulating failures.
