With the proliferation of devices to provide full GPS, AHRS, magnetic compass, pitot-static, ADSB, weather, charts, airport info, engine status, you name it and display it either on a dedicated EFIS and/or EMS or feed it to an ordinary tablet computer, it's quite possible to put all the functions necessary for VFR flight on one screen. That obviously sets up a situation where a software crash, hardware failure or electrical system anomaly could rob you of all instrument readings, which would be bad even in clear VFR conditions.
So, it seems prudent or have a minimal analog mechanical backup to the pretty screens. That would also provide a certain continuity as the electronics become obsolescent and are upgraded or replaced over time. At the same time, you don't want to fully duplicate the glass which would defeat the weight and cost savings of the modern electronics.
So what would be the minimal lightweight backup analog mechanical instrument set? Off the top of my head, I am thinking something like this, all 2 1/4" size if round gauges:
--Lift reserve indicator roughly calibrated for airspeed in level flight or ordinary ASI
--Single-pointer altimeter or Microtim (battery)
--Mechanical compass
--Mechanical slip-skid ball
--Mechanical or electric tachometer (battery) or Tiny Tach (battery)
--Mechanical, preferably miniature, oil pressure and temperature gauges
--Backup instrument lighting (battery) if equipped for night VFR
The two pitot-static instruments would have separate lines and ports from those feeding the EFIS. Personally, I like things simple and I can see having the first four flight instruments above placed at the top of the panel for primary use with the pretty screens secondary. The instruments above would also keep you legal if you wanted to fly without the gadgets at all.
Is there anything I missed or anything unnecessary I included?
Cheers,
Matthew
So, it seems prudent or have a minimal analog mechanical backup to the pretty screens. That would also provide a certain continuity as the electronics become obsolescent and are upgraded or replaced over time. At the same time, you don't want to fully duplicate the glass which would defeat the weight and cost savings of the modern electronics.
So what would be the minimal lightweight backup analog mechanical instrument set? Off the top of my head, I am thinking something like this, all 2 1/4" size if round gauges:
--Lift reserve indicator roughly calibrated for airspeed in level flight or ordinary ASI
--Single-pointer altimeter or Microtim (battery)
--Mechanical compass
--Mechanical slip-skid ball
--Mechanical or electric tachometer (battery) or Tiny Tach (battery)
--Mechanical, preferably miniature, oil pressure and temperature gauges
--Backup instrument lighting (battery) if equipped for night VFR
The two pitot-static instruments would have separate lines and ports from those feeding the EFIS. Personally, I like things simple and I can see having the first four flight instruments above placed at the top of the panel for primary use with the pretty screens secondary. The instruments above would also keep you legal if you wanted to fly without the gadgets at all.
Is there anything I missed or anything unnecessary I included?
Cheers,
Matthew
