Narrative:

When it came time to taxi; I asked pilot not flying to query ATC if we could depart off of runway 28R; intersection echo. After starting engines; ATC approved our runway 28R/east request; and assigned a new altitude of 3;000. On the taxi; pilot not flying reprogrammed the FMS with the new runway and queried ATC as to our departure instructions. ATC confirmed to fly the PORTE3 departure off of 28R. Prior to receiving takeoff clearance; I verified that 28R had been entered into the FMS; which it had. I briefed again that we would depart in LNAV mode and maintain 3;000; with the autopilot engaged. After receiving takeoff clearance; we took off from runway 28R/east. I engaged the autopilot. Shortly after takeoff; my FMS needle turned to the right approximately 60 degrees and the aircraft began making the turn. I asked pilot not flying to verify the turn we were making. Prior to the turn or after the turn began; we had a system annunciation indicating a 'steering fail.' though the FMS was loaded with the departure; the autopilot was following the needle to the right. Using the navigation control panel pilot not flying tried to switch to green needles but was unable. With the autopilot off; we wanted to verify what heading we we going to turn back to. Pilot not flying tried to engage LNAV however it would not accept the input. He then tried to verify the next waypoints on the FMS even though they didn't appear to be coupled to the CDI. Prior to initiating a turn back to the left; we were processing what the guidance was indicating; the failures; level off; turbulence; radio traffic and wanted to verify what our heading should be before making a turn back to the left. I started to make a turn back to the left at which time ATC gave us a heading to the left. Pilot not flying was able to verify that the 28R; PORTE3 departure was in the FMS. ATC gave us direct czq; which the FMS accepted. However; LNAV or any other lateral guidance would not engage on the left side. The rest of the flight was coupled to the right side.during this situation; there was no conflict with another aircraft or terrain. The navigation selector began taking input again by the end of our flight but the left side never accepted anything accept heading mode and would not capture altitude as well. In retrospect; turning to the left would have avoided the entirety of this situation. With that said; having multiple navigation problems; communicating in the cockpit our next turn; communicating with ATC; turbulence; having not flown very much together as a crew; were all contributing factors to what happened. Maintenance was able to clear the steering fail message and resetting the aircraft via a hard shut down seemed to clear the LNAV issues. The navigation controller continued to work. After having the necessary sign-offs; the next day flying we had another problem with the navigation controller. This time the controller hard failed. We again were unable selected any mode of navigation. On this flight; I wrote this item up as being hard failed. Maintenance found a faulty wire under the right side glare shield which was replaced and the navigation controller on both sides began working again. It was believed that the position of the wire affected whether the navigation control panel functioned or not.

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Original NASA ASRS Text

Title: Gulfstream II flight crew reports autopilot malfunction during departure from SFO on the PORTE 3 departure from Runway 28R. A right turn is initiated instead of the left turn at 2;500 FT as depicted. An FMS 'Steering Fail' annunciation is observed but the crew was slow to turn back to left until ATC issued a heading.

Narrative: When it came time to taxi; I asked pilot not flying to query ATC if we could depart off of Runway 28R; intersection Echo. After starting engines; ATC approved our Runway 28R/E request; and assigned a new altitude of 3;000. On the taxi; pilot not flying reprogrammed the FMS with the new runway and queried ATC as to our departure instructions. ATC confirmed to fly the PORTE3 Departure off of 28R. Prior to receiving takeoff clearance; I verified that 28R had been entered into the FMS; which it had. I briefed again that we would depart in LNAV mode and maintain 3;000; with the autopilot engaged. After receiving takeoff clearance; we took off from Runway 28R/E. I engaged the autopilot. Shortly after takeoff; my FMS needle turned to the right approximately 60 degrees and the aircraft began making the turn. I asked pilot not flying to verify the turn we were making. Prior to the turn or after the turn began; we had a system annunciation indicating a 'steering fail.' Though the FMS was loaded with the departure; the autopilot was following the needle to the right. Using the NAV control panel pilot not flying tried to switch to green needles but was unable. With the autopilot off; we wanted to verify what heading we we going to turn back to. Pilot not flying tried to engage LNAV however it would not accept the input. He then tried to verify the next waypoints on the FMS even though they didn't appear to be coupled to the CDI. Prior to initiating a turn back to the left; we were processing what the guidance was indicating; the failures; level off; turbulence; radio traffic and wanted to verify what our heading should be before making a turn back to the left. I started to make a turn back to the left at which time ATC gave us a heading to the left. Pilot not flying was able to verify that the 28R; PORTE3 Departure was in the FMS. ATC gave us direct CZQ; which the FMS accepted. However; LNAV or any other lateral guidance would not engage on the left side. The rest of the flight was coupled to the right side.During this situation; there was no conflict with another aircraft or terrain. The NAV selector began taking input again by the end of our flight but the left side never accepted anything accept heading mode and would not capture altitude as well. In retrospect; turning to the left would have avoided the entirety of this situation. With that said; having multiple navigation problems; communicating in the cockpit our next turn; communicating with ATC; turbulence; having not flown very much together as a crew; were all contributing factors to what happened. Maintenance was able to clear the steering fail message and resetting the aircraft via a hard shut down seemed to clear the LNAV issues. The NAV controller continued to work. After having the necessary sign-offs; the next day flying we had another problem with the NAV controller. This time the controller hard failed. We again were unable selected any mode of navigation. On this flight; I wrote this item up as being hard failed. Maintenance found a faulty wire under the right side glare shield which was replaced and the NAV controller on both sides began working again. It was believed that the position of the wire affected whether the NAV control panel functioned or not.

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.