I'm not looking for replies - although you are welcome to if you like .=C2
- This posting is simply food for thought.
I built a RV-8 with dual busses that can be split.=C2- Each buss can be p
owered by its own ships battery (2 batteries on board - one forward and one
aft) and each buss can power all critical items.=C2- (Note - the engine
is not electrically dependent since I use P Mags)=C2- I installed two EFI
Ss - one primary and the second is mainly used as an engine monitor, but it
can also convert to the backup attitude/nav EFIS in case the primary fails
.=C2- Additionally, each EFIS has its own backup battery.=C2- So, with
multiple redundancies, I felt comfortable with using it in IFR.=C2- That
is not to say that the RV is a stable platform in IMC, especially when hand
flying - but that is another story for another time.
So, I am in VFR pattern, left base to final, in turbulent air, and I someho
w bumped one of the multifunction buttons on the primary display.=C2- ( T
hat is another subject worthy of discussion - that is, being able to make s
elections or changes on the EFIS during bumpy flight conditions)=C2- When
I bumped the button, both EFISs went blank.=C2- Confusing, needless to s
ay.=C2- Now I have no airspeed indications - in fact, I have no indicatio
ns at all!=C2- So, I simply set a power setting that I knew would work (a
nd my AOA was still functional), so landing was fairly straight forward.=C2
- =C2-BUT, I thought - what if that had happened in IMC?!?=C2- Of cou
rse, in IMC one would simply engage the autopilot and command it to level f
light, but there would still be that moment of confusion.
What happened was I had bumped a multifunction button that controlled the d
imming function on the EFIS.=C2- I wired them such that dimming one EFIS
simultaneously dimmed the other. I couldn't think fast enough during a crit
ical phase of flight to analyze what might have happened.
Lessons learned - 1. Know how to quickly readjust the dimming function.=C2
- 2. While it is convenient, consider not wiring the dimming functions to
gether - rather make each EFIS independently dimmable.
