EC225

[JimL]

EC225,

See the answer given by HC in post #215.

Jim

[gnow]

DPATO and DPBL on EC 225

Just like to compare notes ...our DPATO is V1 and 50 ft and DPBL is V1 at 40 ft above deck . DPATO looks fine but I have this feeling that the DPBL is a little too low and fast...Appendix 9 says that the DP is 40 ft above decl and Ground Speed of 10 kts. Wonder what the rest of the EC 225 operators have selected as their DPBL and DPATO.
How does your NHP call when approaching DPBL and DPATO? It sounds like a good mouthful when saying the whole thing at that critical moment of the flight path. Anyone calling these points "Decision Points"?

[HeliComparator]

At the very least that will be the mass provided by the lesser of: maximum certificated take-off mass; compliance with Second Segment Climb Performance (from the clear area CAT A performance graphs); or the OEI en-route climb requirement (which is identical to PC1).

Plus of course twin engine in ground effect hover, however for most helis this is not the limiting factor, the OEI performance at 1000' above the takeoff / landing point is. In Bristow we use out of ground effect hover, though again the 1000' performance is normally the limiting one.

FACEC225 we switch the HTG for TRU 3 after 1st engine start, just after we turn on the Aux Pump. However Refer to the RFM Supplement 12 which tells you to turn it on after second engine start, but it doesn't matter, either is OK. Turning it on after 1st engine start means it will be at the required temperature when you want to do the test of the TRU3 after second engine start even it if is very cold.

when we have enter payload,we can find the vtoss indicator,we have the figure,is it necessary to change the figure for ourself operation?if we change what kind of effct to operation?many thanks

In addition to my earlier post, just to say that you should not change the calculated Vtoss for offshore takeoff or landing, since it will tell you the earliest time you can start to raise the nose on an OEI takeoff or go-around (at indicated Vtoss - 10kts), and thus minimise height lost and maximise the chance of missing the sea!

Just like to compare notes ...our DPATO is V1 and 50 ft and DPBL is V1 at 40 ft above deck . DPATO looks fine but I have this feeling that the DPBL is a little too low and fast...Appendix 9 says that the DP is 40 ft above decl and Ground Speed of 10 kts. Wonder what the rest of the EC 225 operators have selected as their DPBL and DPATO.
How does your NHP call when approaching DPBL and DPATO? It sounds like a good mouthful when saying the whole thing at that critical moment of the flight path. Anyone calling these points "Decision Points"?

We don't specifically refer to DPATO but we raise the nose at V1 (calculated Vtoss - 10 kts) so the helicopter will start climbing as soon as possible. With an engine failure before V1 you will have to lose some height to achieve Vtoss, but at what point you pass DPATO is difficult to say because of the variations of wind, remaining dropdown, pilot technique etc. I am not sure that it matters - what matters is to try to reach Vtoss before you hit the sea! If you have not reached Vtoss but have to level off due to the proximity of the surface, it will then depend on whether you can accelerate in level flight, or if level flight is causing you to decelerate. If the former, you will fly away, if the latter, you need to make a decision to ditch, ie inflate the floats, warn the pax and the flare off the speed and plonk it down at as low a speed as you can manage.

For landing, there are 4 possible outcomes of having an engine failure on approach:

1) you fly a sucessful go-around
2) you land safely on the deck
3) you cannot sucessfully go-around and have to ditch
4) you hit the rig structure somewhere, probably below helideck level.

Outcomes 1 to 3 are all quite safe (normally you would only have to ditch if winds were fairly light, so the heli should remain upright)

Outcome 4 is probably fatal, this is the one you must avoid.

Therefore the landing decision point is when you can no longer go-around without hitting the structure (never mind if the go-around might result in a ditching). Between that decision point and arrival, there may be some exposure to outcome 4) above, but hopefully just a couple of seconds. When you reach DPBL I don't know and it cannot really be worked out because of the same variations of wind, structure obstacles, pilot technique etc - it doesn't matter! What matters is the decision whether to attempt a go-around or continue with the landing, and that is where outcome 4 must be considered the primary issue.

HC

[gnow]

HC,

I totally agree with you on the DPATO and DPBL. These figures can never be a single set of figures. However this would be one of the questions that auditors like to ask and it may look good to have the figures! Like I mentioned in my posrt I was trying to "compare notes" with other operators. I have read an oil company 's Aviation Services Standards and Best Practice and there were several pages on the calculating of the above points.

[gnow]

This happened to me today. At about 10 nm to the airport in the cruise, the ENG light illuminated, NR Fadec comes on in VMS and NR went to 103.8%. At the same time the AMC 1 failure occurs. On checking with the status page it says AMC 1 fail and FADEC 2 fail.
AMC 1 failed ..no problem, just reconfigure and use AMC 2.
FADEC 2 failure..a bit tricky here as the FADEC LIGHT was not on. I raised and lowered the collective slowly and and found that the NR remained at 103.8% so it is not a FADEC failure and no securing of the engines.
After landing when No 2 eng was retarded to IDLE the GOV light comes Flashing on.
Anyone has experienced this not in the book malfunction before?

[HeliComparator]

I have read an oil company 's Aviation Services Standards and Best Practice and there were several pages on the calculating of the above points.

I sometimes wonder why the oil companies bother to use aviation service providers - they are clearly so much better at flying helicopters than we are! Or to put it another way, someone who doesn't understand the issues had to write a checklist sheet with enough tick-boxes to satify their boss and so get their bonus!

[HeliComparator]

This happened to me today. At about 10 nm to the airport in the cruise, the ENG light illuminated, NR Fadec comes on in VMS and NR went to 103.8%. At the same time the AMC 1 failure occurs. On checking with the status page it says AMC 1 fail and FADEC 2 fail.
AMC 1 failed ..no problem, just reconfigure and use AMC 2.
FADEC 2 failure..a bit tricky here as the FADEC LIGHT was not on. I raised and lowered the collective slowly and and found that the NR remained at 103.8% so it is not a FADEC failure and no securing of the engines.
After landing when No 2 eng was retarded to IDLE the GOV light comes Flashing on.
Anyone has experienced this not in the book malfunction before?

This is an AMC failure, not a FADEC failure.

Important point: The pilot should never act on anything they see on the STATUS page, it is really only for advice to the technicians.

FADEC failure is only indicated by the FADEC caption on the VMS engine page and the red repeater light near the engine switch

When the AMC fails the Nr datum stops being received by the FADEC so it reverts to its own datum. Since the FADEC does not have access to the airspeed data, it cannot reduce Nr down to 100% at higher speeds, hence the 103.8% in the cruise. The only device that has ARINC data connection with the FADEC is the AMC, so with AMC failure the FADEC has to work in isolation, including using its own pressure and temperature sensors which are less accurate than the airframe sensors. Probably because of this the flashing Gov is triggered and stored, to be displayed on shutdown even if the triggering problem has been dealt with.

We find that, compared to the other boxes on the aircraft, the AMC is fairly unreliable. Whilst it may recover in your case following a reboot, it is likely to fail again soon and so the best course of action is to replace it.

HC

[gnow]

HC,
The No 2 Fadec was replaced and aircraft went back to service. In my case even after reconfiguration the to AMC 2 the Nr remained at 103.8%. In any case I will have to pay more attention to he AMC on this aircraft now. You are right ..the AMCs in our fleet also tend to give a bit of hiccups every now and then

[drakkar]

Gnow, as HC has written, it's probably an AMC problem.
below 60 Kts, the AMC computes NR then FADECs take over to keep NR at 100%.
If it happens again, try to press the NR/ILS. This switch commands the NR to be reduced at 97,8% via the AMC. The vibration level will be more comfortable and if you have control over the AMC, you can rule out one option.

Drakkar

[gnow]

Normal Transmission Oil Pressure

In view of the recent ditching , I would like to compare notes again on the normal indicated transmission oil pressure. On the RFM it mentioned that Min Trans Oil Pressure is 0.4 bar.so it implies that anything above that figure is normal. However in the MGB drawings it says MP light comes on if the sensor senses a pressure of less than 3.7 bars. I have not seen many 225 flying with a MGB oil pressure of more than 3.7 bars on the MGB oil pressure gauge. I believe the MP light does not come on because the MGB oil pressure gauge taps its pressure after the oil has been splashed on the gearbox whereas the pressure switch for the MP light is just after the MP.
Any inputs on your indicated MGB oil pressure is appreciated

[HeliComparator]

Gnow, you are correct, the gauge measures the pressure at the far end of the oil galleries, whereas the MP pressure switch is at the inlet to the oil filter. Typically the indicated pressure will be 2.8 to 3.5 or so in flight. The indicated pressure when the MP light activates at 3.7 bar, is around 2.1 bar depending on oil temperature. Have a look at the relationship between MP and gauge pressure next time you shut down.

On the RFM it mentioned that Min Trans Oil Pressure is 0.4 bar.so it implies that anything above that figure is normal

No, it implies that anything below 0.4 is an emergency situation. Anything between 0.4 at the MGB.P switch and 3.7 at the MP switches is abnormal, and anything above 3.7 at the MP switch (roughly 2.1 bar at the gauge) is normal. However, if the pressure is normally indicating 3.5 bar, and one day it is suddenly indicating 2.2 bar, I would want to know why! Maybe an internally leaking solid pipe from the pumps etc due to cracks etc!

On our fleet, each day when we do the EPC we write down the oil temperatures and pressures for engines and gearbox (as well as cruise altitude and OAT) on a sheet that stays in the cockpit. So a pilot can look back to see what is "normal" for that particular aircraft.

HC

[clockman]

OILP

What are the Flight Manual OILP instructions for the EC225LP and which component, MGB or engine, is it please? Which was it in the 10may12 North Sea ditching? i note from HeliComparator below that you have pressure gauges too - on both MGB and engine?
I have found TCDS.R.002 Page 16 to 20 Issue 08, 20 January 2011, but it says nothing other than oil contents. Does Certification not check bearing life at oil pressures just below the OILP warning level? Does it merely presume no oil at all and therefore immediate shutdown, which is surely an extreme and unlikely situation during flight. A bearing failure may be costly since it could damage compressor and/or turbine blades and casings too, but what are the probability numbers associated with all this? Is a ditching better than trying to keep flying? Nope, because of the potential loss of life! See EASA 2007.C16.

[forwardassist]

Clockman, do your trolling elsewhere.

[clockman]

Extended Ops

Email sent: Date 13may2012 Time 13h18

To FAA, EASA, CAA, at
FAA Certification Office <[email protected]>
EASA Certification Office <[email protected]>
EASA AD <[email protected]>
EASA Report <[email protected]>
CAA Info <[email protected]>

Re: Helicopter Bearings Certification

Please consider introducing a helicopter certification requirement that requires the continuing operation of a faulty drive train for one hour with an OILP warning, noting that for such an event to occur in flight, it is most unlikely that either oil level or oil pressure will have reduced to zero, and that the bearing will still have residual oil content for a short time too. Bearing design evaluation required of course, and longer gear train spray cooling time.

My request is triggered by the 10may2012 ditching of Eurocopter Super Puma EC225 into the North Sea, apparently because of an OILP warning, and that the return to Aberdeen from the Oil Rig was 150 nm total - so halfway is 75 nm, and he slowed to 80 kts, so one hour needed to get you on "land" from anywhere.

Thankyou to all twin engined helicopter pilots for supporting such thinking - I hope you have already asked of course!
jimq

[clockman]

Unfortunately, the Special Bulletin S2-2012 shown on the UK AAIB website, says they ditched because a warning lit.
jimq

[RotaryWingB2]

I'm pretty sure you'll find that the FLM says, if you have a MGB P caption and a EMLUBE caption 'Land immediately' or words to that effect.

To get this the aircraft down safely, and wthout any injuries is a incredible feat, and in NO way an over reaction by the crew.

[PlasticCabDriver]

That's right, the AAIB report says they ditched because "a warning lit". And not:

- WARN red light and aural gong
- MGB.P caption illuminating on the Central Warning Panel (CWP)
- CAUT amber light
- XMSN caption illuminating on the CWP
- M.P and S/B.P illuminated on the vehicle monitoring system (VMS)
- SHOT illuminated on the MGB control panel
- Zero indication on the main gearbox oil pressure gauge.
In addition, CHIP illuminated on the VMS and the MGB oil temperature started to increase.

Or

The crew activated the emergency lubrication system.
During the descent, the MGB EMLUB caption illuminated on the CWP, for which the associated procedure is to land immediately.

Guess the AAIB must have got it wrong.

[Epiphany]

Clockman is either intellectually challenged or a Troll. Either way ignoring his comments is probably the bst course of action.

[clockman]

Extended Ops

1) I started with #236, to request a DESIGN FOR MUCH LONGER TIME when an OILP warning lit. I stick by that, but it seems my post has been misinterpreted as follows:
2) #237 was published AFTER the UK AAIB SB S2-2012 was available on 13mai2012.
3) #239 i certainly agree - they had a relatively SAFE ditching. Good piloting.
4) #240 provides the detail in the AAIB SB, in which the final item is that they ditched because a warning lit, and not because of a failure to fly.
5) #241 should think again please, for you are in the wrong game.

And thus #240 CONFIRMS the need for #236. Do you now agree?

Please all write to the OFFICIALS to say so - DEMAND DESIGN CHANGE, for YEARS have passed on this OFFICIALS FAILURE.

jimq

[clockman]

Triple failure

Todays helicopter instructions count for what they are - coping with the current design, and shutdown with a REAL warning is necessary if the cost of doing so, is less than the cost of continung to get you home. And that MAIN ROTOR must not fail as it did on G-REDL on 1april2009.

ETOPS was introduced on Civil fixed wing twin engine cruisers, so that if one engine failed, the other would still get you home, across half the Atlantic if ncessary.

So, a twin engined helicopter has to have enough power to stay airborne, and there is not enough power if one is shutdown, so throttle the problem one back, and use an emergency rating on the good one.

You need oil to keep an engine or gearbox running at max rating, but throttling back saves a load of force on a bearing. There is only one Main Rotor, and therefore there is only one final gearbox drive - it must not fail. Throttling back on a helicopter Main Rotor is to reduce airspeed - there will be a balance of airspeed against time to failure without high oil pressure. This needs design assessment to provide aircrew with some helpful info.

And, if you think about your whole AIRCRAFT DESIGN before Certification in this situation, you can optimise it to reduce the probability of ditching further. The Super Puma has two main oil pumps and a single failure stopped them both. And then the backup glycol system (which is there to cool the gears not to lubricate them) showed a warning - the odds are stacking up now - how could that happen? We are in triple failure territory now, and such a series of failures should never have happened.

The design certification procedures are ...... good enough? Or not? At least the emergency glycol system on the Super Puma was created as a back up of sorts, so somebody was thinking, but at a low cost level, not at strategic design.

What DRIVES improved design? OPERATORS and PILOTS should be complaining too ........ the cost of a ditching is surely counted in big numbers, especially if lives are lost.
jimq