Sikorsky S-92: From Design to Operations
I guess similar (lots is)
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Just looking at it, appears to be the same.
I personally don't like cross-feeding the engines if I don't have to, although I have no such restriction. I've heard horror stories of flaming out a motor when you push the selector to cross-feed due to corrosion in the valve. Then again it could be an urban legend.
I personally don't like cross-feeding the engines if I don't have to, although I have no such restriction. I've heard horror stories of flaming out a motor when you push the selector to cross-feed due to corrosion in the valve. Then again it could be an urban legend.
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Do they know yet what caused this? I see from the diagram that there are both dual vents and high level sensors. How high was the pressure being used to refuel? What is the limit?
Hi Outwest:
Hope this partially answers your question.
If the delivery pump pressure is unknown, or exceeds 3.8 bar (55 psi), then
gravity refuel must be used.
[3.8 Bar or 55PSI should give you Approx 120 USG or 100 IMPG or 840 Lbs or 454 LTRS / Minute (providing I got the math right.)]
There are primary and secondary high level pre-check tests to be carried out when commencing pressure refueling to confirm that the high level switches in the tanks will cut off refueling at the proper time.
Max fuel capacity with pressure refueling 764 USG 2890 Ltrs 5175 LBS.
Max fuel capacity with gravity refueling 713 USG 2700 Ltrs 4830 LBS.
Hope this partially answers your question.
If the delivery pump pressure is unknown, or exceeds 3.8 bar (55 psi), then
gravity refuel must be used.
[3.8 Bar or 55PSI should give you Approx 120 USG or 100 IMPG or 840 Lbs or 454 LTRS / Minute (providing I got the math right.)]
There are primary and secondary high level pre-check tests to be carried out when commencing pressure refueling to confirm that the high level switches in the tanks will cut off refueling at the proper time.
Max fuel capacity with pressure refueling 764 USG 2890 Ltrs 5175 LBS.
Max fuel capacity with gravity refueling 713 USG 2700 Ltrs 4830 LBS.
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Thanks for that Albatross,
From what you describe that means that power must be applied to the a/c to pressure refuel. The 61 system does not need dc or ac power to activate the high level shut-offs. Sometimes the old ways are better
Although the Sikorsky limit for the 61 is 50 psi, we have a company limit of 30. If you have ever been standing in the cabin of a 61 taking fuel at 50 psi you will know why......the sound is scary
So, assuming that the checks were carried out, does this mean that BOTH vents were plugged/obstructed?
Nick, if one vent was obstructed and the refueling was at the limit (55 psi), would that cause this?
p.s. Albatross, are you sure it can take MORE fuel with pressure than gravity?
From what you describe that means that power must be applied to the a/c to pressure refuel. The 61 system does not need dc or ac power to activate the high level shut-offs. Sometimes the old ways are better
Although the Sikorsky limit for the 61 is 50 psi, we have a company limit of 30. If you have ever been standing in the cabin of a 61 taking fuel at 50 psi you will know why......the sound is scary
So, assuming that the checks were carried out, does this mean that BOTH vents were plugged/obstructed?
Nick, if one vent was obstructed and the refueling was at the limit (55 psi), would that cause this?
p.s. Albatross, are you sure it can take MORE fuel with pressure than gravity?
Last edited by Outwest; 2nd Mar 2008 at 08:01.
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I recall a base transitioning to H-60s having burst tanks and found the civilian refuler pumping well over 55 PSI as "No one told me it pumped at less than the H-1!"
Our pilots are taught to start engines in crossfeed and then go to main just prior to takeoff to "Ensure the crossfeed lines are purged and full."
Our pilots are taught to start engines in crossfeed and then go to main just prior to takeoff to "Ensure the crossfeed lines are purged and full."
Outwest; what an inquisitive man you are! 
"The 61 system does not need dc or ac power to activate the high level shut-offs. Sometimes the old ways are better."
Apparently Sikorsky believes that the old ways are better and is awash with traditionalists. No power need be applied to the a/c. if pressure refueling. The power for the precheck and the high lever cutoff switches are powered by the Batt Utility Bus which is hot at all times. Of course if refueling to a specific level rather than just "Full" or "Please put in 1500 liters." then you need either AC or DC external power or the APU operating and APU GEN operating.
"p.s. Albatross, are you sure it can take MORE fuel with pressure than gravity?"
Yes I am sure it can take MORE fuel with pressure than gravity. Notice position of fuel caps is not on top of the sponsons.
Not all that much of a difference 51 USG or 26.5 a side.
Trust me - I never lie!
Thanks for all the questions - they make me get into the books to try and confirm truth and enlightenment. Make the smallest mistake in grammar, punctuation, syntax or aircraft systems on these forums and these folks will be all over you like Hyenas on a gut wagon.
"The 61 system does not need dc or ac power to activate the high level shut-offs. Sometimes the old ways are better."
Apparently Sikorsky believes that the old ways are better and is awash with traditionalists. No power need be applied to the a/c. if pressure refueling. The power for the precheck and the high lever cutoff switches are powered by the Batt Utility Bus which is hot at all times. Of course if refueling to a specific level rather than just "Full" or "Please put in 1500 liters." then you need either AC or DC external power or the APU operating and APU GEN operating.
"p.s. Albatross, are you sure it can take MORE fuel with pressure than gravity?"
Yes I am sure it can take MORE fuel with pressure than gravity. Notice position of fuel caps is not on top of the sponsons.
Not all that much of a difference 51 USG or 26.5 a side.
Trust me - I never lie!
Thanks for all the questions - they make me get into the books to try and confirm truth and enlightenment. Make the smallest mistake in grammar, punctuation, syntax or aircraft systems on these forums and these folks will be all over you like Hyenas on a gut wagon.
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Well Albatross, when I stop asking questions and learning stuff I'll be..... you know the rest
So as I understand the 92 high level shut-offs are electrically powered, but off a "hot" buss. The 61 system needs no electric power whatsoever, nil, nada, if you want full tanks. They are strictly mechanical unless as you say you only want a certain amount.
So if fuel caps are not on top of the sponsons does that mean if you top it off with pressure fueling and open the fuel cap you are going to get a bath?
Yes, I agree this place can get nasty if you don't have your facts straight
So as I understand the 92 high level shut-offs are electrically powered, but off a "hot" buss. The 61 system needs no electric power whatsoever, nil, nada, if you want full tanks. They are strictly mechanical unless as you say you only want a certain amount.
So if fuel caps are not on top of the sponsons does that mean if you top it off with pressure fueling and open the fuel cap you are going to get a bath?
Yes, I agree this place can get nasty if you don't have your facts straight
Last edited by Outwest; 2nd Mar 2008 at 22:05.
"So if fuel caps are not on top of the sponsons does that mean if you top it off with pressure fueling and open the fuel cap you are going to get a bath?"
You are correct in your assumption.
In order to prevent this sad state of affairs there is a "window" in the fuel cap which is "silver" when no fuel is present and "Black" when there is fuel at or above the level of the cap.
In addition to being an aid during the preflight walkaround in order to confirm that the air has been removed from the tanks this thoughtful design feature is also useful when pressure refueling in order to know when the tanks are nearly full.
It is wise to check before pressure refueling that no "helpfull" soul, mistakenly anticipating gravity refueling, has opened one of the fuel caps.
(especialy the opposite, starboard, #2 side, cap)
You are correct in your assumption.
In order to prevent this sad state of affairs there is a "window" in the fuel cap which is "silver" when no fuel is present and "Black" when there is fuel at or above the level of the cap.
In addition to being an aid during the preflight walkaround in order to confirm that the air has been removed from the tanks this thoughtful design feature is also useful when pressure refueling in order to know when the tanks are nearly full.
It is wise to check before pressure refueling that no "helpfull" soul, mistakenly anticipating gravity refueling, has opened one of the fuel caps.
(especialy the opposite, starboard, #2 side, cap)
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Thanks for taking the time to post those shots Albatross......as they say a picture is worth a ......
Will still be interesting to find out what caused the burst sponson......
Will still be interesting to find out what caused the burst sponson......
Rotorfix,
I think you'll find that it was not 'High level shut-off valve related' - as the tank was not full it seems more likely to be an air venting problem. Another operator had the same problem, but on land. There seem to be two separate problems that have the same outcome.
Thanks for the gen on the TR problem - I knew it had happened but didn't know the RIPS harness detachment was effect and not cause
I think you'll find that it was not 'High level shut-off valve related' - as the tank was not full it seems more likely to be an air venting problem. Another operator had the same problem, but on land. There seem to be two separate problems that have the same outcome.
Thanks for the gen on the TR problem - I knew it had happened but didn't know the RIPS harness detachment was effect and not cause
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Three out of 6 (or possibly only 5) Scatsta based S-92's went kaput yesterday including one that has overnighted on deck of North Cormorant. Give me back ma tigers, not half as comfy but they got me home on time more often.
As one of the guys who sit down the back what does 'maint comp fail' mean? Couple of us noticed it on display all way out from Scatsta two trips back and are curious.
Cheers
Joe
As one of the guys who sit down the back what does 'maint comp fail' mean? Couple of us noticed it on display all way out from Scatsta two trips back and are curious.
Cheers
Joe
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Regarding the elastomeric bearing failure. This is nothing new for Sikorsky. Has happened on the hawk series many times. But, a tech rep told me the occurrence rate has gone way down thank to some improved bonding method.
Guess they need to improve the improvement!
Guess they need to improve the improvement!
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I would say the same consequences as a tail rotor rips harness coming adrift (as they do), I believe that the last incident referred to caused considerable damage to the stabiliser assy. Are there going to be any plans to reduce the inspection interval of these tail pivot bearings ? I would have thought this would be quite a cause for concern, such an important component failing.
NST
NST
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What does 'maint comp fail' mean?
The Maintenance Data Computer has failed.
The Maitenance Data Computer (MDC) tracks and records aircraft system information, and monitors individual aircraft systems subcomponents down to the sensor level. The MDC monitors and records the performance of approximately 256 individual components. These components and their operational condition can be displayed on any of the cockpit displays and enable the pilot to monitor the status of aircraft systems and to initiate a buiit in test of components. The MDC also controls some helicopter systems eg avionics cooling fans and fuel prime pumps.
The Maintenance Data Computer has failed.
The Maitenance Data Computer (MDC) tracks and records aircraft system information, and monitors individual aircraft systems subcomponents down to the sensor level. The MDC monitors and records the performance of approximately 256 individual components. These components and their operational condition can be displayed on any of the cockpit displays and enable the pilot to monitor the status of aircraft systems and to initiate a buiit in test of components. The MDC also controls some helicopter systems eg avionics cooling fans and fuel prime pumps.
Are there going to be any plans to reduce the inspection interval of these tail pivot bearings ?
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S-92 with 5 main blades?
I recall (or dreamed) something about a 5-bladed S-92 with more powerful engines or was this on someone's wish list way back when the S-92 was being nit-picked?
Any validity to this rumor (or dream)?
Any validity to this rumor (or dream)?