A PA-46 pilot suffered several avionics and autopilot malfunctions but continued his approach in bad...

Attributes
ACN	945127
Time
Date	201104
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	PA-46 Malibu/Malibu Mirage/Malibu Matrix
Operating Under FAR Part	Part 91
Flight Phase	Initial Approach
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 45 Flight Crew Total 805 Flight Crew Type 190
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Inflight Event / Encounter Loss Of Aircraft Control
Miss Distance	Horizontal 500

Narrative:

Coming home in 'hard' IMC with fairly heavy wind and mod rain; two miles of visibility and ceilings of 400-500; were given heading 120 to intercept the ILS; descend to 3;000 with the autopilot armed for approach. The garmin 530 switched from GPS to vloc. Tuned and identified the localizer and glideslope was pegged but alive but no localizer showed up? So I flew pink line on the mfd. I was probably five miles outside of the FAF at 3;000 right on magenta line. About two or three miles outside the FAF the plane took off at 1;000 FPM ascent. I was overpowering autopilot; disconnected it and the pitch wheel was set (appropriately) by autopilot to climb so by the time I could disconnect autopilot and re-trim I was at nearly 3;600 ft! I quickly got my wits about me and realized there was no localizer; I descended to catch the glideslope while hand flying and trying to stay on the magenta line but went low just outside the FAF and got a low altitude alert from the tower. I said I was correcting and climbed; centered the glideslope and followed the magenta line (illegally; but it was all I could do; short of diverting to a VFR airport); toward the airport. Broke out at 400 AGL and landed. I was not pleased with the autopilot. Did I do something wrong? We have had gremlins like this before.

Original NASA ASRS Text

Title: A PA-46 pilot suffered several avionics and autopilot malfunctions but continued his approach in bad weather utilizing track guidance from his GPS; breaking out at 400 FT and landing safely.

Narrative: Coming home in 'hard' IMC with fairly heavy wind and mod rain; two miles of visibility and ceilings of 400-500; were given HDG 120 to intercept the ILS; descend to 3;000 with the autopilot armed for approach. The Garmin 530 switched from GPS to VLOC. Tuned and identified the localizer and glideslope was pegged but alive but NO LOCALIZER showed up? So I flew pink line on the MFD. I was probably five miles outside of the FAF at 3;000 right on magenta line. About two or three miles outside the FAF the plane TOOK off at 1;000 FPM ascent. I was overpowering autopilot; disconnected it and the pitch wheel was set (appropriately) by autopilot to climb so by the time I could disconnect autopilot and re-trim I was at nearly 3;600 FT! I quickly got my wits about me and realized there was no LOC; I descended to catch the glideslope while hand flying and trying to stay on the magenta line but went LOW just outside the FAF and got a low altitude alert from the Tower. I said I was correcting and climbed; centered the glideslope and followed the magenta line (illegally; but it was all I could do; short of diverting to a VFR airport); toward the airport. Broke out at 400 AGL and landed. I was not pleased with the autopilot. Did I do something wrong? We have had gremlins like this before.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

A PA-46 pilot suffered several avionics and autopilot malfunctions but continued his approach in bad weather utilizing track guidance from his GPS; breaking out at 400 ft and landing safely.