Flight Crew Air Transport Pilot (ATP); Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 90; Flight Crew Total 7352; Flight Crew Type 1110
Troubleshooting; Workload
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Unstabilized Approach
Flight Crew Overcame Equipment Problem
Aircraft; Human Factors
Arriving the terminal area at KOKC I was receiving radar vectors for the ILS Rwy 17L approach and was on a downwind in IMC descending to 5;000 feet MSL. The controller subsequently vectored me to a heading of 310 and a descent to 4;000 feet. During the descent and while monitoring the heading I noticed that the flight director started commanding a turn to the right. I disconnected the Autopilot (AP) and hand flew with raw data while cycling the AP. During this troubleshooting it was busy because I was receiving descents and vectors for the ILS and configuring the aircraft for the approach; which included significant speed reduction. As the approach continued I lost the #1 Nav data; the pilot artificial horizon showed a left bank while the copilot artificial horizon showed a bank to the right; and I started getting altitude flags on the pilot altimeter with rapid changes in the indicated altitude. The copilot instruments were indicating correct information; however; it was impossible to see the glideslope indicator on the copilot HSI without leaning across the cockpit because it was hidden from view by parallax. I advised ATC that I was experiencing multiple problems on the pilot instruments with conflicting information being presented; and was flying using right side (copilot) instruments. I continued the approach and experienced a great deal of over-control issues due to the high workload introduced at a critical time in flight. I experienced substantial course deviations during the approach but did not have a full scale deflection of the copilot course indicator at any time during the approach. I maintained a higher than normal airspeed and altitude on the ILS to insure that I did not descend below the glideslope for the approach and make it less difficult to perform an abort of the ILS. I broke out slightly to the left of course at approximately 1/4 mile from the runway and about 200 feet higher than normal. There was more than adequate runway to land from this position so I landed slightly long after being cleared for the visual approach and cleared to land at that point. The Approach Controller did a superb job of assisting me on the approach and switched me to tower during the roll out phase. Taxi in was non-eventful.A better decision on my part would have been to ask for vectors for another approach during which time I could have configured the aircraft at a more normal pace and been much more prepared to fly a partial panel approach instead of trying to sort out technical problems and aircraft configuration changes while flying single pilot. This would have provided for a less stressful and more stable approach with increased safety.
BE20 pilot reported losing multiple flight instruments on approach to OKC.