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BE33 pilot experiences a signal loss on his GPS during a visual approach at night with the GPS providing lateral guidance. When the signal is reacquired the autopilot is engaged and the aircraft attempts to return to the IAF. During the confusion an altitude deviation occurs.
| Attributes | |
| ACN | 926211 |
| Time | |
| Date | 201012 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | Bonanza 33 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | Descent |
| Route In Use | Direct |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | GPS & Other Satellite Navigation |
| Person 1 | |
| Function | Single Pilot |
| Qualification | Flight Crew Commercial |
| Experience | Flight Crew Last 90 Days 20 Flight Crew Total 2200 Flight Crew Type 2000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Altitude Excursion From Assigned Altitude Deviation - Procedural Clearance |
Narrative:
[I] was originally cleared to the IAF for GPS xx. Sunset had occurred; and the approach is not permitted at night; so with the appearance of VFR conditions; I elected to switch my approach to a visual. I was cleared direct to the airport; and given a descent to 2;500 MSL. My GPS was programmed direct to the IAF and coupled to the autopilot. Unfortunately the new clearance came as my GPS lost signal; so I set a 500 ft decent on my autopilot and switched to a heading about 15 degrees left of my course; or approximately direct to the airport. With night and broken clouds; I started to scan visually to determine if I could visually place my position waiting on my GPS to come live again. As my aircraft started to approach 2;500 ft my GPS came live. I had forgotten to reprogram it since it was in inactive mode; so when I pressed GPS/navigation on my autopilot; the plane turned back to the IAF. I started button pushing; and eventually uncoupled the autopilot; but not before descending to about 2;200 ft. Once I noticed it; I started to ascend back to 2;500 and turn back to the airport. ATC called to see how I was doing; and by that time I could see the airport; so canceled at that time. As I reflect on the event; it is obvious that I needed to keep ahead of the GPS and the subsequent autopilot couplings. Although is useful to have the GPS hold it's last known heading when signal is lost; I needed to amend my clearance with ATC to a heading; and set up the GPS to return to my new; intended clearance once signal is returned. I fly this route quite frequently; and could pinpoint my ground position quite precisely; thus allowed my cockpit organization to lapse. Admittedly; loss of signal with GPS is a more baffling situation than years past with radio navigation; where one's position and geometry was more defined.
Original NASA ASRS Text
Title: BE33 pilot experiences a signal loss on his GPS during a visual approach at night with the GPS providing lateral guidance. When the signal is reacquired the autopilot is engaged and the aircraft attempts to return to the IAF. During the confusion an altitude deviation occurs.
Narrative: [I] was originally cleared to the IAF for GPS XX. Sunset had occurred; and the approach is not permitted at night; so with the appearance of VFR conditions; I elected to switch my approach to a visual. I was cleared direct to the airport; and given a descent to 2;500 MSL. My GPS was programmed direct to the IAF and coupled to the autopilot. Unfortunately the new clearance came as my GPS lost signal; so I set a 500 FT decent on my autopilot and switched to a heading about 15 degrees left of my course; or approximately direct to the airport. With night and broken clouds; I started to scan visually to determine if I could visually place my position waiting on my GPS to come live again. As my aircraft started to approach 2;500 FT my GPS came live. I had forgotten to reprogram it since it was in inactive mode; so when I pressed GPS/NAV on my autopilot; the plane turned back to the IAF. I started button pushing; and eventually uncoupled the autopilot; but not before descending to about 2;200 FT. Once I noticed it; I started to ascend back to 2;500 and turn back to the airport. ATC called to see how I was doing; and by that time I could see the airport; so canceled at that time. As I reflect on the event; it is obvious that I needed to keep ahead of the GPS and the subsequent autopilot couplings. Although is useful to have the GPS hold it's last known heading when signal is lost; I needed to amend my clearance with ATC to a heading; and set up the GPS to return to my new; intended clearance once signal is returned. I fly this route quite frequently; and could pinpoint my ground position quite precisely; thus allowed my cockpit organization to lapse. Admittedly; loss of signal with GPS is a more baffling situation than years past with radio navigation; where one's position and geometry was more defined.
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.