I had my first experience flying partial panel in IMC on Monday, coming home from Boston. It wasn’t the classic partial panel — a vacuum failure — but a failure of the attitude indicator instrument itself, followed by the airspeed indicator while I was on an ILS approach. The AI had been sluggish for a while, but I had told myself that it was still usable as long as I allowed for a few seconds’ lag. In IMC and moderate turbulence (with a bit of light icing to distract me), however, it was totally useless, and I ended up relying on the turn coordinator to keep the wings more-or-less level, with the heading indicator as a backup.
I’ve heard that partial panel in a slick plane with retractable gear can be a nightmare, but the Cherokee is so slow, draggy, and spiral-resistant that it wasn’t more than an irritant. I’m not sure that simulated partial panel under the hood does anything to prepare you for it, though, because the hardest part is recognizing that you have a problem in the first place (I’m also not convinced that flying under a hood does much to prepare you for flying in actual IMC, but that’s another posting.)
Losing the ASI wasn’t a big deal, since I was already on the glideslope and had a 10,000 ft runway ahead of me, so I just kept a generous power setting on the tachometer and burned off the extra speed in a long flare.
The plane is grounded until the pitot system is cleaned out and tested, the AI is fully overhauled, and new wiring is installed for the intermittent landing light.