I have a panel with a single GRT EFIS HX, MGL ASX-1 digital ALT/ASI, TT DF II autopilot, and GRT EIS. In addition, I have stand-alone, battery-operated GPS capability.
Cruising to OSH in smooth air with the EFIS controlling the autopilot in roll and pitch, the nose began abruptly oscillating up and down. I pushed the autopilot's ALT button to stop EFIS pitch control and the oscillations immediately stopped. Several times later in the flight, I tried EFIS pitch control and was always rewarded with mild pitch transients. If the EFIS cannot smoothly control the autopilot in pitch (as it has not for years), I can terminate EFIS control. Break. Break.
On the return from OSH, I took off early Saturday in MVFR weather and was able to get on top 50 miles west. Ten minutes later, the EFIS backlight failed. It came back on for a few seconds about 1 minute later and then stayed off for the next 6 hours. Cycling EFIS power did not help.
With the sun at my back and shining directly on the screen, I was just able to interpret some symbols and words but for the most part, the EFIS was hard if not impossible to interpret. Later when the sun rose to the point that the EFIS was shadowed by the glare shield (as it would have been in IMC), I was only able to interpret parts of the display when holding an LED Maglite against the screen at a 45-degree angle. I navigated among EFIS screens using my memory of soft key functions because the menus were unreadable even with the flashlight. Twice, I had to soft boot the EFIS because I had pressed a wrong key and became lost someplace in the menu trees.
Think about all the data on the EFIS screen that would not have been available without a visible EIS for engine and fuel data, backup GPS for navigation, stand-alone autopilot* to hold the wings level and maintain vertical speed (perhaps a luxury in VMC but a necessity in IMC and a real work saver in an RV in choppy air), and separate ALT/ASI. Thanks to the non-EFIS sources, I really only missed easy access to corrected fuel quantity (but had a paper copy of the correction tables) and XM NEXRAD, TAF, and METAR information (very nice to have in any conditions but I was VMC). And, thanks to the Maglite, I had access to almost everything on the EFIS a square inch at a time.
* I have an older version of the TT DF control head, one with an internal magnetometer; so, if the GPS input from the EFIS were to fail, the control head would lose track information but its display would revert to magnetic heading. The newer (improved?) version of the DF head does not have a magnetometer and thus provides far less redundancy for the EFIS.
John Nystrom
Placitas, NM
RV-7A N7VD
RV-3B N3NU
Cruising to OSH in smooth air with the EFIS controlling the autopilot in roll and pitch, the nose began abruptly oscillating up and down. I pushed the autopilot's ALT button to stop EFIS pitch control and the oscillations immediately stopped. Several times later in the flight, I tried EFIS pitch control and was always rewarded with mild pitch transients. If the EFIS cannot smoothly control the autopilot in pitch (as it has not for years), I can terminate EFIS control. Break. Break.
On the return from OSH, I took off early Saturday in MVFR weather and was able to get on top 50 miles west. Ten minutes later, the EFIS backlight failed. It came back on for a few seconds about 1 minute later and then stayed off for the next 6 hours. Cycling EFIS power did not help.
With the sun at my back and shining directly on the screen, I was just able to interpret some symbols and words but for the most part, the EFIS was hard if not impossible to interpret. Later when the sun rose to the point that the EFIS was shadowed by the glare shield (as it would have been in IMC), I was only able to interpret parts of the display when holding an LED Maglite against the screen at a 45-degree angle. I navigated among EFIS screens using my memory of soft key functions because the menus were unreadable even with the flashlight. Twice, I had to soft boot the EFIS because I had pressed a wrong key and became lost someplace in the menu trees.
Think about all the data on the EFIS screen that would not have been available without a visible EIS for engine and fuel data, backup GPS for navigation, stand-alone autopilot* to hold the wings level and maintain vertical speed (perhaps a luxury in VMC but a necessity in IMC and a real work saver in an RV in choppy air), and separate ALT/ASI. Thanks to the non-EFIS sources, I really only missed easy access to corrected fuel quantity (but had a paper copy of the correction tables) and XM NEXRAD, TAF, and METAR information (very nice to have in any conditions but I was VMC). And, thanks to the Maglite, I had access to almost everything on the EFIS a square inch at a time.
* I have an older version of the TT DF control head, one with an internal magnetometer; so, if the GPS input from the EFIS were to fail, the control head would lose track information but its display would revert to magnetic heading. The newer (improved?) version of the DF head does not have a magnetometer and thus provides far less redundancy for the EFIS.
John Nystrom
Placitas, NM
RV-7A N7VD
RV-3B N3NU
