GI-275
I have read this report a few times since I have two GI-275s installed in my Mooney. What I have, is not what the report claims is in the incident aircraft. The difference being the options and setup configuration. There are three units available from Garmin: A basic unit, a unit with a battery and an ADAHRS board, and a unit with a battery, ADAHRS board and autopilot reference. To replace the attitude indicator, the incident aircraft had the unit with a battery and ADAHRS configured as a Primary ADI (attitude and direction indicator). In this configuration, only the ADI page will display. There was no autopilot in the airplane so it did not have the autopilot reference board (unlike my airplane).
The second unit in that plane had the battery and ADAHRS and was configured as a Primary HSI. When configured as a Primary HSI, it will only display the HSI and HSI + Map pages. It will not display anything else. When configured this way, it will not automatically revert to an ADI if the other unit fails. There will be will be no reversionary switch installed on the panel. Other standby instruments must remain in the panel and this airplane still had the old airspeed, altimeter and T&B. Yes both units in this airplane were the same but configured differently.
Why anyone would spend the exact same money to install the exact same unit configured as a Primary HSI versus what I have, a MFD/Standby ADI
is beyond my comprehension. As a MFD/Standby ADI it will automatically revert to being an ADI if it senses something is amiss with the Primary ADI. There is also a required revisionary switch installed on the panel that would change from whichever page is being used to the Standby ADI page. Configured as a MFD/Standby ADI, many pages are available: first always will be ADI, and in order selected by the installer, HSI, HSI Map, Map, CDI, Traffic, Terrain. If you followed this, you're probably realize the versatility
of the MFD and wonder why they configure the 2nd unit as a Primary HSI. The pilot was not the owner, wonder if the pilot realized he wasn't dealt the full hand.
As to the failure itself, the picture in the report showed airspeed. track not heading, no pitch or roll. Was that an actual picture soon after? 14 Climbing 15,000 in Canada in January, and it hit the fan when entering the clouds. Was ice involved? Was the pitot heat on? Will a frozen over pitot show 0 airspeed or last airspeed? Realize a 6000 hour ATP rated pilot with a failed attitude indicator ought to be able to fly partial panel on those steam gauges unless he had no airspeed. And he apparently didn't realize he exceeded VNE by 70 knots until Garmin told on him.
Why did the ADI fail to begin with? Don't know. You can bet Garmin is looking at the data. But the instrument configuration was so short-changed by the installer, there may be some other lacking in the installation.