Police helicopter crashes onto Glasgow pub
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I guess exactly the same as for other displays.
No hood, but NVG-compatible displays(*). See my #2610.
(*) again, this doesn't mean the displays can be read through NVGs, but that they don't glow, so do not interfere with the use of NVGs.
No hood, but NVG-compatible displays(*). See my #2610.
(*) again, this doesn't mean the displays can be read through NVGs, but that they don't glow, so do not interfere with the use of NVGs.
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The front and rear police screens are of the flat TFT/LCD variety, the front screen generally has a shroud with a flip down shield on the right side to minimise glare, most pilots do however like to see the screen as it's natural to position the aircraft relative to the target without being asked to do so, so that the camera never goes out of control and the pilot and rear observer can see the target on the ground. The screen is dimmed and does not present a problem.
On a visit to another region I did see that their aircraft had a very small repeater screen fitted to the pilots coaming to assist with situational awareness, looked great, but just like the sheepskin seat covers it's an extra cost to justify.
On a visit to another region I did see that their aircraft had a very small repeater screen fitted to the pilots coaming to assist with situational awareness, looked great, but just like the sheepskin seat covers it's an extra cost to justify.
Actually Art,
The last set of sheepskin seat covers were about a third of the price of the EC ones, they last up to 3 years longer than the EC ones and are much more comfortable to sit on in both summer and winter.
Just dug out the paperwork - 4 point harness type - £308 delivered for the sheepskin as opposed to 974 euros plus ECUK "Standard" delivery for the EC type.
The last set of sheepskin seat covers were about a third of the price of the EC ones, they last up to 3 years longer than the EC ones and are much more comfortable to sit on in both summer and winter.
Just dug out the paperwork - 4 point harness type - £308 delivered for the sheepskin as opposed to 974 euros plus ECUK "Standard" delivery for the EC type.
Last edited by Fortyodd2; 3rd Mar 2014 at 14:44.
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40odd
Thanks, think it was North Mids seat covers we saw, finally got the boss to buy them once our 'standards' had worn out (again!) and in blue too! If they've been good enough for the forces for years.....
Thanks, think it was North Mids seat covers we saw, finally got the boss to buy them once our 'standards' had worn out (again!) and in blue too! If they've been good enough for the forces for years.....
Extract from IN
Attached are some extracted pages from a recent Information Notice to expand on Information on the logic of the fuel supply indication.
The pages have been redacted and altered with some additional information and changes to reflect incorrect or non standard terminology.
The manufacturer really needs a native EN speaking technical writer!
The pages are by no means conclusive and there is a lot of information NOT included so before commenting too much please read previous posts.
It does however give a good indication of the supply system layout to allay the lunatic fringe.
Usual caveats apply and -
As these are anonymous forums the origins of the contributions may be opposite to what may be apparent.
In fact the press may use it, or the unscrupulous, or sciolists*, to elicit certain reactions.
The pages have been redacted and altered with some additional information and changes to reflect incorrect or non standard terminology.
The manufacturer really needs a native EN speaking technical writer!
The pages are by no means conclusive and there is a lot of information NOT included so before commenting too much please read previous posts.
It does however give a good indication of the supply system layout to allay the lunatic fringe.
Usual caveats apply and -
As these are anonymous forums the origins of the contributions may be opposite to what may be apparent.
In fact the press may use it, or the unscrupulous, or sciolists*, to elicit certain reactions.
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Which is why, at lower fuel states, the total fuel remaining needs regular re-calculating, by adding up all three tanks, and pilots should NEVER turn both transfer pumps off.
Dependant on attitude, you want one or other transfer pump to move any useable fuel into a place where it can feed your engine(s) until you've landed safely.
The closer you get to MLA, the more frequently you calculate endurance - to MLA, not to dry tanks - and the more aware you should become of the likelihood of captions. Although anything below about 100 in the main tank will likely have generated one caption already, depending on attitude.
I, or someone else, has posted it before, but the slightly corrupted quote from Samuel Johnson (1709-1784) "The prospect of being hanged focuses the mind wonderfully" works well in aviation the closer one works to the published limits. The phrase regularly moves forward in my mind whenever the sphincter tightens!!
Dependant on attitude, you want one or other transfer pump to move any useable fuel into a place where it can feed your engine(s) until you've landed safely.
The closer you get to MLA, the more frequently you calculate endurance - to MLA, not to dry tanks - and the more aware you should become of the likelihood of captions. Although anything below about 100 in the main tank will likely have generated one caption already, depending on attitude.
I, or someone else, has posted it before, but the slightly corrupted quote from Samuel Johnson (1709-1784) "The prospect of being hanged focuses the mind wonderfully" works well in aviation the closer one works to the published limits. The phrase regularly moves forward in my mind whenever the sphincter tightens!!
Can you clarify something
These two things do not seem to be the same - which is correct?
1)
and this from point 5 here
2)
1)
pilots should NEVER turn both transfer pumps off.
Dependant on attitude, you want one or other transfer pump to move any useable fuel into a place where it can feed your engine(s) until you've landed safely
Dependant on attitude, you want one or other transfer pump to move any useable fuel into a place where it can feed your engine(s) until you've landed safely
2)
The pilot does not perform a manual action to switch to the supply tanks. The supply tanks are automatically and continuously fed fuel from the main tank.
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What is meant is that you don't have to move a selector to switch to the supply tanks once the main tank is empty (as you have to do on light aircraft).
I.e. you don't have such a selector on the EC135.
I'm not a native english speaker, but had no problem understanding that. Is it because I think mostly in French?
I.e. you don't have such a selector on the EC135.
I'm not a native english speaker, but had no problem understanding that. Is it because I think mostly in French?
Pitts,
Both statements are correct.
All the information you need to understand why is in this thread - but, just to give you a clue - where do the engines take the fuel from?
The diagrams above are the best yet to be posted. Digest them along with the info that Sid has posted and work it out.
Both statements are correct.
All the information you need to understand why is in this thread - but, just to give you a clue - where do the engines take the fuel from?
The diagrams above are the best yet to be posted. Digest them along with the info that Sid has posted and work it out.
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"The supply tanks are automatically and continuously fed fuel from the main tank."
I contend that if the above statement is true this accident would not have happened. A fully automatic system would not require the pilot to select the pumps to ON (or OFF) and the suggested 'automatic and continuous fed fuel from the main tank' would have reached the supply tanks and then the engines. It did not, because it is not automatic.
I contend that if the above statement is true this accident would not have happened. A fully automatic system would not require the pilot to select the pumps to ON (or OFF) and the suggested 'automatic and continuous fed fuel from the main tank' would have reached the supply tanks and then the engines. It did not, because it is not automatic.
"The supply tanks are automatically and continuously fed fuel from the main tank."
Granted, as so many EC-135 operators have pointed out, Art being the latest, it is not automatic.
It may be that the attorney for Eurocopter/Airbus Helicopters would be able to competently explain this away and point to the actual features and functions of the system ... buy why put out misleading info like that on the official site?
Makes no sense to me. zorab64: very nice post, thank you.
LW50,
If you want to follow that lead try reading the Australian CASA Regulations which have been written by "legal" folk.
Completely unintelligible to humans.
Cultural differences and language barriers do apply to some of these statements that are made.
For instance the PRIME pumps were referred to as supply tank pumps in the
document but that terminology is not used in the RFM or the AMM.
Can be hard work some times.
If I were an attorney, I might get a little mileage out of such an official statement in a civil case
Completely unintelligible to humans.
Cultural differences and language barriers do apply to some of these statements that are made.
For instance the PRIME pumps were referred to as supply tank pumps in the
document but that terminology is not used in the RFM or the AMM.
Can be hard work some times.
Very clear and helpful diagrams RVDT.
Whilst they highlight the effects of spillage through the overflow, and address the consequences of different pitch fore and aft, they are silent on the consequences of lateral pitch. It seem just as obvious that fuel would still "spill" back into the main tank, but not necessarily at the same rate for each supply tank, depending on the angle and duration of bank. The transfer pumps can only supply fuel equally to the supply tanks, so assymetrical fuel spillage will only be remedied when there is sufficient fuel in the main tank to more than fill the supply tanks. As the equal flow from the transfer pumps fills the tanks, the one with more fuel will be filled first, and the excess will overflow back to the main tank, and so on until both tanks are full. Not so easy when total fuel is at or below supply tank capacity, and of course not possible with the transfer pumps off. With the transfer pumps off, there must exist the possibility for there to be a flight profile which results in the supply tanks holding close to the same volume of fuel as opposed to the designed-in difference.
Were such a situation to arise, engine flameouts could be much closer together than expected...
Whilst they highlight the effects of spillage through the overflow, and address the consequences of different pitch fore and aft, they are silent on the consequences of lateral pitch. It seem just as obvious that fuel would still "spill" back into the main tank, but not necessarily at the same rate for each supply tank, depending on the angle and duration of bank. The transfer pumps can only supply fuel equally to the supply tanks, so assymetrical fuel spillage will only be remedied when there is sufficient fuel in the main tank to more than fill the supply tanks. As the equal flow from the transfer pumps fills the tanks, the one with more fuel will be filled first, and the excess will overflow back to the main tank, and so on until both tanks are full. Not so easy when total fuel is at or below supply tank capacity, and of course not possible with the transfer pumps off. With the transfer pumps off, there must exist the possibility for there to be a flight profile which results in the supply tanks holding close to the same volume of fuel as opposed to the designed-in difference.
Were such a situation to arise, engine flameouts could be much closer together than expected...
A coordinated angle of bank will have no effect on differential spillage of the two supplytanks as the gravity vector will allways point straight down...
skadi
skadi
Reduced fuel asymmetry
@falcon900
It has been mentioned in this thread that the aircraft flies left side low in the cruise.
Given the now reported fuel tank geometry it would appear that this could only increase the fuel asymmetry.
On the other hand, never having looked into an open bucket of fuel in flight, it does seem quite possible that a few litres could have slopped from one supply tank to the other just as the levels began to fall in a manner that reduced the fuel asymmetry from the designed ~5 litres. Within a few minutes the levels would have fallen and prevented any further slopping.
It has been mentioned in this thread that the aircraft flies left side low in the cruise.
Given the now reported fuel tank geometry it would appear that this could only increase the fuel asymmetry.
On the other hand, never having looked into an open bucket of fuel in flight, it does seem quite possible that a few litres could have slopped from one supply tank to the other just as the levels began to fall in a manner that reduced the fuel asymmetry from the designed ~5 litres. Within a few minutes the levels would have fallen and prevented any further slopping.
JimJim, Skadi,
I agree with what you are saying, but the design assymetry is only 4kgs to start with. With the ability of fuel to be displaced out of the overflows and from side to side, and with the transfer pumps off, is it totally inconceivable that some combination of manoeuvering/ buffeting caused this to be reduced?
I am looking for a scenario which would have caused the second flameout to have followed very closely on the first, before the pilot had an opportunity to figure out what was going on. It is beginning to feel like a bit of a lost cause, but I am still trying!
I agree with what you are saying, but the design assymetry is only 4kgs to start with. With the ability of fuel to be displaced out of the overflows and from side to side, and with the transfer pumps off, is it totally inconceivable that some combination of manoeuvering/ buffeting caused this to be reduced?
I am looking for a scenario which would have caused the second flameout to have followed very closely on the first, before the pilot had an opportunity to figure out what was going on. It is beginning to feel like a bit of a lost cause, but I am still trying!