S76C semi Glass panel with DAFCS

[WLM]

Hi Guys

Would you fly this aircraft if u had no AP1/AP2 functioning in IMC conditions? the DAFCS is FZ760 model by the way; our MEL states that if 1 of the AP is available, either 1 or 2, we can fly IMC??? furthermore after repeatably snagging the aircraft, it is simply released into service with the same know defect....

Of course we can fly the aircraft manually, ie no APs, and only with the AFCS mode then as per the standard S76C model but then u loose the AFCS and you're in IMC??? then what, on CAT A ops...

I have refused to fly this unit 3 times in IMC conditions but now looked at as being a troublemaker....
:sad:

[Nigel Osborn]

You have to follow your MEL requirements which should also state how long it is acceptable to have 1 system u/s.

[212man]

Well the FAA MMEL says this about the SHZ-760 DAFCS:

May be inoperative for:
a) VFR operations.
OR
b) One helipilot may be inoperative for two pilot IFR operations provided one pitch, roll, and yaw channel
remains operative and limitations listed in the RFM and applicable supplements are complied with.

So, it's not clear if you are talking about a two pilot or single pilot operation.

More to the point, is not whether you can fly with one helipilot (for 3 days, in this case) but that the snag is being continuously re-defered.

[WLM]

Thanks Nigel and 212

Yes I am well aware of the MEL and it seems we carry the FAA standard issue onboard; it's a 2 pilots ops btw

BUT what I am getting at, is leaving under VMC, legal as far as clause 1, then entering clouds above 2000' for extended period, ie IMC also legal as far as far as clause 2 if u have 1 pitch/yaw/roll; Which FAA moron decided it was ok to do so needs to be shot as if u loose AP2, you have no FD functions whatsoever left under AP1....

And that is exactly what the engineers are playing with, ie the fact that the MEL state it's ok to do so with only 1 AP functioning; I would like to see them in the combined monsoon scenario clouds, rain, thunder, gusting winds and see how they feel about it...

Cheers
WLM

[The Governor]

If the MEL says it's approved then you should possibly accept that the folks who certified the RFM may know what they are talking about.

You're not suggesting you need a fully functioning flight director for 2 instrument rated pilots to recover an aircraft to VMC with a servicable AP working one channel? As you said you are able to fly the aircraft manually.

If you are concerned about losing the remaining AP channel then limit your operations to VMC. If that is not practical youre going to fight a losing battle refusing to fly a servicable aircraft because you disagree with the MEL.

Flying an S76C with no APs, although allowable VMC, would be fatiguing and I would probably limit my FDP. Flying with one AP channel u/s really makes only a slight difference and just requires a less enthusiastic approach to handling (in my experience anyway). It does mean you won't be able to couple to the FD but that shouldn't really be an issue.

The issue is getting the aircraft servicable so you don't have to repeatably accept defered defects. The MEL is not the problem.

[helimutt]

Hey Gov, you sound like a real company man. Get the job done under any circumstances! :E;) I bet you extend your fdp to help out all the time too?:)

[ShyTorque]

In UK, the issue would be the legality of continued deferring of the defect.

The MEL should also state for how long the defect could be accepted, e.g. ten working days.

[Hullaballoo]

If the MEL says it's approved then you should possibly accept that the folks who certified the RFM may know what they are talking about.

The folks who approved the RFM don't write (or approve) the MEL... The MEL is an operational approval, and not a certification requirement. The RFM and MEL should be consistent, but I suppose that's only in a perfect world.

The MEL should specify how quickly the problem must be corrected. If it's repeatedly happening, you're raising valid questions, as the MEL isn't intended to be a "band-aid."

[The Governor]

You would expect the RFM to be a source document for creating an MEL that is only accepted with the relevant authority approval.

[212man]

The folks who approved the RFM don't write (or approve) the MEL... The MEL is an operational approval, and not a certification requirement. The RFM and MEL should be consistent, but I suppose that's only in a perfect world.

That's true insofar as the MEL is written by the operator, but it is based on the Master MEL (MMEL) which is written by the manufacturer. The MMEL will be written by a group of people that includes the same 'folks' who write the RFM.

In this particular example, the restrictions on flight with a degraded AFCS system will be listed in the RFM Limitations section, but the MMEL will set the time limits before repair (as well as the restrictions.) The main point, as I and others have said, is that the same defect should not be continuously re-defered! That is most certainly against the spirit and intent of the MEL process and points to a poor safety culture.

[Shawn Coyle]

Bit of clarification on MMEL and MEL
MMEL may be written by the manufacturer, but it will be carefully scrutinized by the authorities at very high level. MMEL will be pretty generic and may not include specific bits of equipment.
MEL done by operator using MMEL and scrutinized by local rep of authority. Should include all the Flight Manual Supplements for that serial number airframe.
Worthwhile to check MEL against limitations of basic manual and all supplements to ensure it's covered everything. Operator and local authority rep may not be well trained to develop MEL.

[212man]

That's true Shawn, but it's also a fact that an MEL cannot be less restrictive than the MMEL, so if an operator wishes to include items that are not covered in the 'generic' MMEL the authority will want a lot of good 'gen' to support approval.

I once had to write an MEL before the manufacturer had written the MMEL - it resulted in pretty detailed analysis by all relevant systems specialists and I would say the eventual MMEL was not generic.

One area I think alot of MELs fall down on is not interpreting the 'national authority's' requirements for things like navaids. When a crew is looking through the MEL to see if they can dispatch with a u/s DME, the last thing they need to see is 'As required by local regulations'!

[Hullaballoo]

The MMEL will be written by a group of people that includes the same 'folks' who write the RFM.

To clarify: that may be true in your part of the world, but is not in the U.S. The MMEL is approved by the Aircraft Evaluation Group, which is a part of Flight Standards (ie, operations). The RFM is approved by Flight Test Pilots/Flight Test Engineers, as part of the certification requirements of Part 27/29; they need not be included in the MMEL approval process, although that would be ideal.

In fact, the MMEL grants relief to the RFM because an aircraft doesn't meet its type design (meaning everything is installed and functional). Consequently, RFM limitations (say, for a busted AFCS) assume the failures occur in flight; the MMEL assumes they occur before takeoff and are known to the crew. Therefore, the MMEL may impose additional limitations, such as minimum crew requirements or flight conditions (VFR), in addition to when the corrective action must take place.

[SpareParts]

About the original question and not about MEL regs.

I assume your flying a standard configuration S76 right?

So therefor if you loose one autopilot you can no longer fly coupled but you will retain your sas from both autopilots unless the whole computer is completely toast. But even in that case the remaining autopilot computer takes 100% movement authority giving the same control as two autopilots. So you need to be specific why the one autopilot is U/S? Is the computer hooped or are you getting like a trim failure or w/e and the autopilot de-couples.

I know its frustrating to fly without being able to be coupled to the flight director but the aircraft is still just as safe. Infact literally all you loose is a convienance more than anything seeing as there are many many halicopters out there that fly IFR operations with nothing more than a Autopilot SAS system installed. The S76 is even type certified in the states for single pilot IFR with only one functioning autopilot. Theres no where out there that says the Flight director needs to be operable to fly the aircraft safely. Bluntly just because you can't couple doesn't mean the autopilot isn't working.

I think the nature of the fault more detailed then just A/P U/S would be necessary for anyone here to give a proper opinion on whether or not the helicopter is safe or not.

Cheers
SP

[212man]

S76 is even type certified in the states for single pilot IFR with only one functioning autopilot

That's not what the RFM says. The limitations section (Part 1, Section 1) clearly states that for SPIFR you need two APs with ATT mode, whereas for two-pilot IFR you only need 1 APP with ATT mode. This matches the MMEL.....strangely enough ;)

[Brian Abraham]

Anyone able to offer an insight why? On the Sperry equipped 76A you could couple with only one system available, but not so on the C version. Sure would have been handy at times - 412 similarly afflicted.

[SpareParts]

Sorry 212man i should re read the RFM before i start going on a long rant lol:} I was wrong about SPIFR. You are correct in that you need two AP's in ATT for that. But the point i was trying to make is that the aircraft is most likely still perfectly safe to fly if your Flight Director wont couple to your AP because many things can cause this happen. Some potentially dangerous and most not life or death so much more detail of the exact fault if known is required to know if the helicopter is safe and fit for flight. I would "ASSUME" the engineers know that the fault is minor and thats why they keep returning the aricraft to service even though you cannot couple.

Brian; on the S76's its all about what operations the aircraft is being used for that dictates its AP coupling limitations.

For example on the 7600 AP's in both 412's and 76's are identical in design but obviously custumized for each aircraft. There is a jumper (or 2 i cant remember off the top of my head) placed between pins on the AP computers that tell them if they are allowed to couple with just one fully functiong AP or not. Its as simple as removing or installing this jumper to change configurations. I'm not absolutly certain on the details but i believe only SAR and EMS aircraft are allowed to fly 3Q with only one fully functional AP. The Sperry 7000 AP system is the same way which you find on older aircraft.

[Shawn Coyle]

And more to the point, do people train with one channel and the FD only?
Do the sims replicate the situation faithfully?