FMEA VH-TBA SDS-EFI.xlsx

	A	B	C	D	E	F	G	H	I	J	K	L
1	RV-14 VH-TBA with SDS EFI - FMEA											Electrical Generation Rev 1
2	In Flight: Normal Switch Positions - L BATT Contactor CLOSED (ON) / R BATT Contactor CLOSED (ON) / X-TIE Contactor OPEN (OFF)
3	- Engine Bus / Essential Bus are tied and can be considered as one bus.
4	- Engine Bus is primarily powered via 'ENG BUS FEED BACKUP' with R BATT and MAIN ALTN as sources.
5	- Engine Bus is alternately fed via 'ENG BUS FEED' with L BATT and MZ30 as sources, or R BATT & MAIN ALTN as source (via X-TIE)
6	Risk	#	Item	Failure Mode	In-Flight Detection	Existing Controls	Liklihood	In-Flight Effect	Immediate System Loss	Severity	Pilot Action	Recovery State

7	Low	1	L Battery	EMS Shutdown (Short on 'L BATT POS' or Overvolt etc)	BATT Fault CAS	Reputable Supplier	Occasional	L Batt unable to feed Engine Bus Side.	Nil - Engine Bus still fed via Main Bus Diode Feed.	No Loss	L BATT to OFF (State Matching) X-TIE OPEN so Engine Bus retains 2 feed paths	If MAIN System needs to be isolated (smoke) then MZ30 is only engine bus souce.
8	Low	2	L BATT Contactor	Fail Open	No Detection	-	Occasional	L Batt unable to feed Engine Bus Side.	See (1)	No Loss	Not Detectible until Shutdown	If MAIN System needs to be isolated (smoke) then MZ30 is only engine bus souce.
9	Low	3	R Battery	EMS Shutdown (Short on 'R BATT POS' or Overvolt etc)	BATT Fault CAS	-	Occasional	R Batt unable to feed Main Bus (or engine bus via diode)	Nil - Main bus still fed via MAIN ALTN. Main alt can still function as L BATT is still in system via 'ENG BUS FEED BACKUP'.	No Loss	R BATT to OFF (state matching)	Normal Ops
10	Low	4	R BATT Contactor	Fail Open	No Detection	-	Occasional	R Batt unable to feed any bus	See (3)	No Loss	Not Detectible until Shutdown	Normal Ops
11	Low	5	X-TIE Contactor	Fail Open	No Detection	-	Occasional	- R BATT and MAIN ALTN have only single feed to engine bus - If ALTN fails, MZ30 cannot supply main bus (non-critical items).	Nil	No Loss	Nil - only detectible as part of non-normal on ground checks. Add to on ground checks? (note 1)	Normal Ops unless MAIN ALTN also fails - acceptable risk.
12	Low	6	MAIN ALTN	- Failure or Overvolt Shutdown etc - Short on B Lead & 70A MIDI Blown	- 'MAIN ALT LOW VOLTS' CAS - EIS MAIN BUS / ENG BUS Volts indications	Using B&C for Additional Reliability	Occasional	- MAIN Bus is fed only by the R BATT	Nil - but time limited now to R BATT endurance	No Loss	- If no action, MAIN BUS will run on R BATT. - X-TIE can be opened to allow MZ30 to power MAIN BUS	- MZ30 is powering both busses with both batteries giving sustenance as required. - No Load shedding is available (Note 2)
13	Low	7	SBY ALTN	-Shear Pin Fail -Regulator Fail -Short on feed & 30A MIDI Blown		Pre-Flight Checks (note 3)	Occasional	Loss of redundancy. If MAIN ALTN fails, then only operating on 2 batteries.	Nil	No Loss	Not Detectible until next runup	MAIN ALTN as pri power source, and if this fails only 2 batteries.
14	Low	8	Wire: L BATT Contactor to STUD or X-TIE FEED	Wire Short	-BOTH BATT Fault CAS -MAIN ALT AMPS 60+	-Common Industry Practice -35mm2 Welding Cable double Sheathed -Crimped ends / Heat Shrink -Cable End Boots	Very Improbable	-Both BATTS Fault and Disconnect -MAIN ALTN would feed to ground via ENG BUS FEED BACKUP / Diode / Engine Bus / ENG BUS FEED (60+ amps) -Diode will likely fail. -MZ30 would see drop in volts and start up, feeding to the short then disconnect.	-Voltage would drop as all power sources to ground. - Both ECU's shutdown	Engine Stop	-Nil Action could correct -If engine not already stopped, MAIN ALT off would stop engine	Engine Stopped
15	Low	9	Wire: R BATT Contactor to STUD or X-TIE Contactor to START CONACTOR	Wire Short	-R BATT Fault CAS -MAIN ALT AMPS 60+ -"SBY GEN ACTIVE" CAS	-Common Industry Practice -35mm2 Welding Cable double Sheathed -Crimped ends / Heat Shrink -Cable End Boots	Very Improbable	-R BATT Fault and Disconnect -MAIN ALT Feeding to Ground (60+ amps) (voltage drop) -Diode should prevent L BATT feeding to ground -MZ30 Kicks into power ENG BUS	- Main Bus would see voltage drop - loss of Equipment on this bus. - ALTN off would lose power to Main Bus	Non-Crit Sys Loss	- DO NOT open X-TIE or Shutdown of ENG BUS would occur.	Loss of Main Bus
16	Low	10	Wire: ENG BUS FEED or ENG BUS FEED BACKUP (between Diode and ENG BUS)	Wire Short	-BOTH BATT Fault CAS -MAIN ALT AMPS 60+	-Common Industry Practice to run bus feeders unprotected -Short potentially would self clear (aka Fat Wire).	Very Improbable	-Both BATTS Fault and Disconnect -MAIN ALTN would feed to ground via ENG BUS FEED BACKUP short -MZ30 would see drop in volts and start up, feeding to the short then disconnect.	-Voltage would drop as all power sources to ground. - Both ECU's shutdown	Engine Stop	-Nil Action could correct -If engine not already stopped, MAIN ALT off would stop engine	Engine Stopped
17	Low	11	Wire: ENG BUS FEED BACKUP before Diode or MAIN BUSS FEED	Wire Short	-R BATT Fault CAS -MAIN ALT AMPS 60+ -"SBY GEN ACTIVE" CAS	-Common Industry Practice to run bus feeders unprotected -Short potentially would self clear (aka Fat Wire).	Very Improbable	-R BATT Fault and Disconnect -MAIN ALT Feeding to Ground (60+ amps) (voltage drop) -Diode should prevent L BATT feeding to ground -MZ30 Kicks into power ENG BUS	- Main Bus would see voltage drop - loss of Equipment on this bus. - ALTN off would lose power to Main Bus	Non-Crit Sys Loss	- DO NOT open X-TIE or Shutdown of ENG BUS would occur.	Loss of Main Bus
18	Low	12	Main Buss	Short of Bus to Ground	-R BATT Fault CAS -MAIN ALT AMPS 60+ -"SBY GEN ACTIVE" CAS	-Good Quality Bussman RTA Fuse Block used. -Exposed bus bar on back of fuse block painted with "Liquid Electrical Tape" -Bus Mounted vertically in Sub Panel, with riveted skin above.	Very Improbable	-R BATT Fault and Disconnect -MAIN ALT Feeding to Ground (60+ amps) (voltage drop) -Diode should prevent L BATT feeding to ground -MZ30 Kicks into power ENG BUS	- Main Bus would see voltage drop - loss of Equipment on this bus. - ALTN off would lose power to Main Bus	Non-Crit Sys Loss	- DO NOT open X-TIE or Shutdown of ENG BUS would occur.	Loss of Main Bus
19	Low	13	Engine Bus	Short of Bus to Ground	-BOTH BATT Fault CAS -MAIN ALT AMPS 60+	-Good Quality Bussman RTA Fuse Block used. -Exposed bus bar on back of fuse block painted with "Liquid Electrical Tape" -Bus Mounted on 45 with back facing down in the "Power Module" panel, protected from instrusion on all sides.	Very Improbable	-Both BATTS Fault and Disconnect -MAIN ALTN would feed to ground via ENG BUS FEED BACKUP / Diode / Engine Bus short -MZ30 would see drop in volts and start up, feeding to the short then disconnect.	-Voltage would drop as all power sources to ground. - Both ECU's shutdown	Engine Stop	-Nil Action could correct -If engine not already stopped, MAIN ALT off would stop engine	Engine Stopped
20	Low	14	Essential Bus or Wire: ESS BUS FEED	Short of Bus to Ground or Wire to Ground	-BOTH BATT Fault CAS -MAIN ALT AMPS 60+	-Wire run from ENG BUS to ESS BUS copper bar is very short, protected with chafe protection and rubber boots on each end. -Horizontal breakers are linked with 0.062" brass, covered in heat shrink except for screw locations. -Vertical linkages are made with #10 Tefzel. -ESS BUS FEED is chafe protected and boots on both ends.	Very Improbable	-Both BATTS Fault and Disconnect -MAIN ALTN would feed to ground via ENG BUS FEED BACKUP / Diode / Engine Bus / ESS BUS Feed Short. -MZ30 would see drop in volts and start up, feeding to the short then disconnect.	-Voltage would drop as all power sources to ground. - Both ECU's shutdown	Engine Stop	-Nil Action could correct -If engine not already stopped, MAIN ALT off would stop engine	Engine Stopped
21	Low	15	ENG BUSS Fat Wire Tie Point	Loose Connection or Corrosion	"SBY GEN ACTIVE" CAS but with no "MAIN ALTN LOW VOLTS"	-Using Quality Parts -Stainless stud to minimise corrosion -non-conductove cover	Occasional	-ENG BUS FEED would lose power to the ENG BUS -MZ30 would see drop in volts and kick in (to no effect). -ENG BUS would remain fed by the ENG BUS FEED BACKUP / Diode from R BATT and MAIN ALTN	Nil	No Loss	Nil Action required. Loss of redundancy in case MAIN ALTN fails.	Likely confustion as to why SBY GEN was active with MAIN ALTN still working.
22	Med	15	ENG BUSS Fat Wire Tie Point	Short to Ground	-BOTH BATT Fault CAS -MAIN ALT AMPS 60+	-Using Quality Parts -Non-Condictive Cover	Improbable	-Both BATTS Fault and Disconnect -MAIN ALTN would feed to ground via ENG BUS FEED BACKUP short -MZ30 would see drop in volts and start up, feeding to the short then disconnect.	-Voltage would drop as all power sources to ground. - Both ECU's shutdown	Engine Stop	-Nil Action could correct -If engine not already stopped, MAIN ALT off would stop engine	Engine Stopped
23	Low	16	MAIN BUS Fat Wire Tie Point	Loose Connection or Corrosion	-Main bus items would shut down (MFD)	-Using Quality Parts -Stainless stud to minimise corrosion -non-conductove cover	Occasional	-Main Buss items would get no power and shut down -MAIN ALTN Buss Sense would see zero volts and try and increase output of alternator. -Regulator would likely shutdown alternator -MZ30 would then see drop in volts and kick up keeping ENG BUS powered.	-Items only powered by MAIN BUSS would be lost.	Non-Crit Sys Loss	- No action could recover the bus. Might be seen as a ALTN FAIL -If pilot opens X-TIE, this would not re-power the BUS.	Loss of Main Bus
24	Low	16	MAIN BUS Fat Wire Tie Point	Short to Ground	-Main bus items would shut down (MFD)	-Using Quality Parts -Non-Condictive Cover	Improbable	-R BATT Fault and Disconnect -MAIN ALT Feeding to Ground (60+ amps) (voltage drop) -Diode should prevent L BATT feeding to ground -MZ30 Kicks into power ENG BUS	- Main Bus would see voltage drop - loss of Equipment on this bus. - ALTN off would lose power to Main Bus	Non-Crit Sys Loss	- No action could recover the bus. Might be seen as a ALTN FAIL -If pilot opens X-TIE, this could result in the shut down of the ENG BUS also.	Loss of Main Bus
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53	Notes / Action Items
54		1	Consider some on ground checks (perhaps at 50 hourly) to check X-TIE is fucntioning. L BATT on (only L screen starts up), X-TIE on (both screens start up) etc.
55		2	If the TOTAL LOAD is above 30A, then since the X-TIE is open, BOTH batteries would deplete slowly. The main power users are PITOT HEAT (and FLAPS) but these can be turned off / not used etc. Need to do a worst case load analysis to see if a MAIN BUS shed relay is needed. If the X-TIE is left OPEN, then the R BATT only would deplete. Better to have this as an alternate source for the engine bus, and shed the main bus if need be. PITOT should remain in ESS BUS as this may be needed for IFR flight. FLAPS can stay on MAIN BUS as these are non-critical.
56		3	SBY gen should be checked at pre-flight, by turning off MAIN ALTN. Sby should kick in with "MAIN ALT LOW VOLTS" and "SBY GEN ON". Bus volts should change from 14.4 volts on MAIN ALTN, to 14.2 volts in SBY GEN. If lower than this, then the MZ30 is not working.
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