Thanks. That was as I suspected.
kwlf wrote:
Out of pure curiosity what is the largest bill that one might reasonably expect for having the alternator debugged and potentially replaced if it malfunctions whilst away from home?
Depends on from where you have to fly the mechanic in …
The challenge is often, that the field you are stranded at either has no repair shop or at least non with a mechanic that you trust enough to use a wrench on your plane. Then it’s getting expensive and time consuming.
Assuming the drive belt is intact (if not, propeller has to come off to change it) it is as Silvaire says.
To bring an engineer out to say south of France is likely to cost you bigger part of 1k and that’s assuming he is a friend. If it is a company then probably 2k; I am basing this on drive-out charges for the FAA altimeter check. Might be better to land somewhere where they have somebody with a spanner.
The TB20 one is best part of 1k though.
On the original Q, I would depart but would
However I now have a backup alternator which with a net 15A output can power most of the plane, so I could just depart and fly home, pitot off. However again I have to add that I don’t have any avionics which need airspeed; an Aspen owner might have issues for example if entering IMC below 0C. Would definitely avoid icing conditions because TKS needs power.
I flew the gazelle helicopter with failed generator from home to maintenance base 45 minutes away. Standard load shedding and using iPhone gps just in case it all failed.
Amazed me that the battery lasted the whole trip no issues at all, even with radio on. I reckon it would have started the engine again!
Same I only need handheld, avgas, tablet and will fly it VMC all the way from Calvi to UK, I always carry jump battery start & plugs for both car & aeroplane and both use 12V connector, the aeroplane battery will last for +30min
Not much different from flying in Cubs/TMGs with no transponders or battery, I would not do that in a Cirrus, there are reasonswhy some aircraft have dual alternators, electric trim and fuel pump transfers being main ones…
Malibuflyer wrote:
The challenge is often, that the field you are stranded at either has no repair shop or at least none with a mechanic that you trust enough to use a wrench on your plane. Then it’s getting expensive and time consuming.
The situation that @kwlf described does not need to be so constrained. It’s a home built, with an Lycoming O-320, easily serviced by the owner. It takes about 10 minutes to remove the cowling on an e.g. RV, about an hour to diagnose the issue with tools carried on board, and about 30 minutes to replace anything that needs to be replaced. Even if as Peter mentioned the drive belt needs replacing and the prop needs to come off, it’s not the end of the world if you have safety wire and pliers with you.
Getting parts is probably the biggest issue, but ordering on your cell phone with overnight delivery is often an option.
I learned how to fly in a plane with no provision for a generator and no battery 
As Peter says, assuming that the belt is intact. ‘Cause if it’s not, you have to remove the prop to replace the belt, and that’s a bigger job. To reduce the urgency of this when I’m in the bush with my Lycoming, I carry this kind of belt:
https://www.myford.co.uk/acatalog/A—-SECTION-LINK-V-BELTING-FOR-THE-HEADSTOCK-DRIVE—70090-1405.html
It can be “built” around the ring gear pulley, and It’ll get me home.
Otherwise, you have understand the electrical load analysis for your plane. When I did the research on a factory Cessna Grand Caravan for battery only operation, in accordance with the guidance for VFR day flying, the battery would provide 30.49 minutes of electrical power, where 30.0 minutes is the requirement – not much reserve beyond the requirement there!
Technically, with no minimum equipement list, you have no argument that you may depart with an inoperative system. So, if you’re going to, you best be very confident that a secondary failure resulting from your decision won’t attract more attention to what you did!
During my helicopter training, while I was lifting out of a confined area (an exercise), the instructor simulated an alternator failure by pressing and illuminating the press to test of the alternator light. I acknowledged that alternator failure, continued picking up, and headed back toward the airport, just a mile away…. “What are you doing?” questioned my instructor with a shocked expression… “I’m returning to the airport with a failed alternator, ‘cause I’m sure not going to put back down into a hole in the bush, and shut down, to have the maintenance guy lug his toolbox through the bush, cursing me the whole way!”. Well… it seems I missed the point. The point of the exercise was to have me land back into the confined area. So, into the hole again. This time, as I picked up, transmission chip light – yeah, that one I’m putting back into the hole for! It seemed that I understood a little too much about the helicopter’s systems, knowing that I did not need the alternator for a mile flight home!
Yes, I have departed an airplane with a failed alternator.
Pilot_DAR wrote:
Technically, with no minimum equipement list, you have no argument that you may depart with an inoperative system. So, if you’re going to, you best be very confident that a secondary failure resulting from your decision won’t attract more attention to what you did!
According to EASA rules you don’t necessarily need a MEL.
NCO.IDE.A.105 Minimum equipment for flight
A flight shall not be commenced when any of the aeroplane instruments, items of equipment or functions required for the intended flight are inoperative or missing, unless:
(a) the aeroplane is operated in accordance with the MEL, if established; or
(b) the aeroplane is subject to a permit to fly issued in accordance with the applicable airworthiness requirements.
So the question is if the system is “required for the intended flight”. Also
ML.A.403 Aircraft defects
(a) Any aircraft defect that seriously endangers the flight safety shall be rectified before further flight.
(b) The following persons may decide that a defect does not seriously endanger flight safety, and may defer it accordingly:
(1) the pilot in respect of defects affecting non-required aircraft equipment;
(2) the pilot, when using the minimum equipment list, in respect of defects affecting required aircraft equipment — otherwise, these defects may only be deferred by authorised certifying staff;
(3) the pilot in respect of defects other than those referred to in points (b)(1) and (b)(2) if all the following conditions are met:
(i) the aircraft is operated under Annex VII to Regulation(EU) No 965/2012 (Part-NCO) or, in the case of balloons or sailplanes, not operated under Subpart-ADD of Annex II (Part-BOP) to Regulation (EU) 2018/395 or not following Subpart DEC of Annex II (Part-SAO) to Regulation (EU) 2018/1976;
(ii) the pilot defers the defect with the agreement of the aircraft owner or, if applicable, of the contracted CAMO or CAO;
(4) the appropriately qualified certifying staff in respect of other defects than those referred to in points (b)(1) and (b)(2), where the conditions referred to in point 3(i) and (ii) are not met.
So here the questions is if the defect “seriously endagers flight safety”. I would argue in the case of a VFR flight where you have planned in advance for how to safely conclude the flight given possibility of loss of electrical power, a dubious alternator is not a defect that seriously endangers flight safety.
Yes Ibra, that’s the link, thanks.
Airborne_Again wrote:
So the question is if the system is “required for the intended flight”
The first questions will be what is the intended flight, ’cause no matter how short, there will be an expectation of the VFR reserve added to the duration of the original intended flight. Knowledgeable pilots know that the design requirement will provide cautious operation for 30 minutes on the battery. And that 30 minutes could be your reserve, leaving a well planned flight having no electrical reserve.
If the pilot understand the systems well, the pilot would know that any aircraft with a fuel pump will have a second electrical fuel pump, and that would be in the seriously endangers flight category during an overshoot during the reserve portion of the flight. Similarly electric flaps or landing gear. So I’d have trouble accepting dispatch of an airplane with an electric fuel pump/flaps/gear, and an inoperative alternator, for anything more than a very brief “hop” flight. For a very simple day VFR only airplane with a minimum electrical system, and only the starter running off the battery, I would agree that you could get airborne, and turn off the master, and fly as long as you like.
