Sikorsky S-76: Ask Nick Lappos
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It is a theorical question based on the RFM part II, section I System Descriptions. Pg. 1-11.
"The 30-second light has the additional function of annunciating that 30-second usage has been recorded. The occurrence of 30-second usage is latched by the DECU and reported by the illumination of the amber light when the engine is not running."
So I want to know if it is possible to start the engine in that condition, when the 30 sec. OEI ball is displayed, caused by a 30-second OEI power usage in the last flight. If starting the engine in these conditions is not possible, what would have to be done to clear the ball out?
Regards,
Rosenthal.
"The 30-second light has the additional function of annunciating that 30-second usage has been recorded. The occurrence of 30-second usage is latched by the DECU and reported by the illumination of the amber light when the engine is not running."
So I want to know if it is possible to start the engine in that condition, when the 30 sec. OEI ball is displayed, caused by a 30-second OEI power usage in the last flight. If starting the engine in these conditions is not possible, what would have to be done to clear the ball out?
Regards,
Rosenthal.
If its anything like other Turbomeca engines, the light will indicate that 30 sec power has been used - not necessarily that 30 sec power has been used for 30 seconds! It would be so much less confusing to call it OEI HI or the like, rather than "30 second power". Anyway, with that light on I would expect you to be able to start, though it might be inadvisable without first having a technician check the engine.
On the Makila 1A2 there is a magnetic reset on the engine. On the 2A it is via a soft key in the cockpit. With the Arriel, due to the age of the original engine, probably the former (reset on the engine) rather than the latter.
On the Makila 1A2 there is a magnetic reset on the engine. On the 2A it is via a soft key in the cockpit. With the Arriel, due to the age of the original engine, probably the former (reset on the engine) rather than the latter.
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Generally, if you use 30 second for any duration where it is a penalty, then the engine can not be insured to last another 30. It pretty well is one and done. Now there are allowables for starts and brief excursions but when these are exceeded it is just too bad.
TC
TC
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The engine usage is logged, but provided the 30 second usage was for less than 30 seconds in any one excursion, you can have up to 2 minutes of cumulative usage until the engine needs to be pulled.
Hi guys,
TC, it is not too bad:
Turbomeca Maintenance Manual stipulates under the "Exceeding the maximum accumulated time of operation at the OEI ratings"
Exceeding the operation accumulated time at the 30-second OEI rating
An accumulated time of 30-second operation at this rating is permitted.
Meaning that as long as you have not used a cumulated 30 sec of this rating, you are allowed to keep the engine in service in full respect the Airworthiness of the aircraft, whatever the category of operation needed.
Then, the modules 3&4 shall be removed for factory reset.
Best
Kami
TC, it is not too bad:
Turbomeca Maintenance Manual stipulates under the "Exceeding the maximum accumulated time of operation at the OEI ratings"
Exceeding the operation accumulated time at the 30-second OEI rating
An accumulated time of 30-second operation at this rating is permitted.
Meaning that as long as you have not used a cumulated 30 sec of this rating, you are allowed to keep the engine in service in full respect the Airworthiness of the aircraft, whatever the category of operation needed.
Then, the modules 3&4 shall be removed for factory reset.
Best
Kami
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You need to be able to take off with the ability to use 30 second power 3 times. Once on takeoff to get you out of harms way, once on an aborted landing, and once on final landing.
S-76D
________________________________________
Can anyone confirm what the NACA ducts on the doors of the S-76D are for?
Fresh Air for the Pax? Must be surely?
________________________________________
Can anyone confirm what the NACA ducts on the doors of the S-76D are for?
Fresh Air for the Pax? Must be surely?
The NACA duct air scoops on the S-76 cockpit and cabin doors are a baseline build standard. However, if the final delivery configuration is a VIP interior option with air conditioning, then the cabin NACA duct air scoops are removed, as the cabin air flow delivery system is redesigned to cater for a more demanding clientele not looking for ram air only cooling
.
Last edited by Hilife; 19th Aug 2012 at 15:52.
Some current aircraft have the DC driven aftermarket ECU/C4 system fitted, leaving the scoops intact externally. The interior wemac vents have been removed and sealed.
Last edited by Sir Korsky; 19th Aug 2012 at 19:02.
S76C++
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C+/++ Inverters
In the C+ RFM the inverters are turned ON after the first engine is started but in the C++ both engines should be started first. Could anyone shed some light on why that is different?
Thanks,
HS
Thanks,
HS
Not like C+ where a stepdown transducer failure looses one 26 VAC bus.
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Collective to yaw coupling felt in controls
Hello all,
Am flying an S76 again after some time away from Sikorskys. One of our two aircraft has noticable feedback from one control to the other, i.e. the collective moves when pushing pedal and vice versa, when making normal control inputs, both during ground taxi and in flight. All pilots notice it but I seem to be the only one who thinks there's something not quite right.
As I understand the system, collective to yaw coupling should not be felt by the pilot in normal flight (only at major control deflections, like when the T/R is at full pitch and additional pedal is added etc.) Any feedback felt between the collective and pedals would indicate a sticking point somewhere.
Are my memory banks foggy? Do I misunderstand the system and is the feedback perfectly normal? Is the rigging off? Is there some binding somewhere?
Hoping the interweb's collective wisdom on the S76 will resolve my anxiety. Thanks!
Am flying an S76 again after some time away from Sikorskys. One of our two aircraft has noticable feedback from one control to the other, i.e. the collective moves when pushing pedal and vice versa, when making normal control inputs, both during ground taxi and in flight. All pilots notice it but I seem to be the only one who thinks there's something not quite right.
As I understand the system, collective to yaw coupling should not be felt by the pilot in normal flight (only at major control deflections, like when the T/R is at full pitch and additional pedal is added etc.) Any feedback felt between the collective and pedals would indicate a sticking point somewhere.
Are my memory banks foggy? Do I misunderstand the system and is the feedback perfectly normal? Is the rigging off? Is there some binding somewhere?
Hoping the interweb's collective wisdom on the S76 will resolve my anxiety. Thanks!
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Revolutionary,
My experience flying a couple of examples of S76A++/C++/D is that the S76 normally has just a tiny bit of adverse collective-to-yaw coupling, especially if the controls are moved rapidly, or if the machine is new and "tight".
As I recall, somewhere in the maintenance manual or the flight check procedures even says something to the effect that a small amount is normal as long as you can overpower it without using excessive force on the collective. I suppose that this is subjective, and what is a "small amount" to one pilot could be "excessive" to another.
If there is excessive collective-to-yaw coupling then it is usually something binding somewhere aft of the mixing unit. Sometimes it is the rigging of the cables going back to the tail rotor, a bad bellcrank bearing, etc.
Also note that there is much more left pedal travel available than right pedal travel before the pedal bottoms out, so if you are checking the feedback between the collective and pedals then it doesn't take much right pedal before the pedal bottoms out and the collective moves up.
Hope this helps
My experience flying a couple of examples of S76A++/C++/D is that the S76 normally has just a tiny bit of adverse collective-to-yaw coupling, especially if the controls are moved rapidly, or if the machine is new and "tight".
As I recall, somewhere in the maintenance manual or the flight check procedures even says something to the effect that a small amount is normal as long as you can overpower it without using excessive force on the collective. I suppose that this is subjective, and what is a "small amount" to one pilot could be "excessive" to another.
If there is excessive collective-to-yaw coupling then it is usually something binding somewhere aft of the mixing unit. Sometimes it is the rigging of the cables going back to the tail rotor, a bad bellcrank bearing, etc.
Also note that there is much more left pedal travel available than right pedal travel before the pedal bottoms out, so if you are checking the feedback between the collective and pedals then it doesn't take much right pedal before the pedal bottoms out and the collective moves up.
Hope this helps