Bonanza 35
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 30; Flight Crew Total 2600; Flight Crew Type 800
Situational Awareness; Human-Machine Interface
Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Aircraft; Human Factors
While I was flying an ILS approach to Runway 23 at ORF; the approach controller reported to me that he had received a low altitude alert. I informed him that I was in good VMC; and I elected to continue at my altitude (800 feet MSL; over open water) rather than climb. He informed me a second time; at which point I climbed to the altitude for the approach; continued; and landed without incident. The situation developed as follows: In my airplane I have a GNS 430W (NAV 1) and an SL30 NAV/COMM (NAV 2). My standard procedure is to use NAV2 for an ILS; reacquired. Since my experience is that once an ILS signal comes in; it stays in (especially since I was not at a sever angle to the approach course) I was not sure I could trust NAV 2; so I set up the ILS frequency in NAV 1; with the intention of switching the CDI from GPS to VLOC (VOR/LOC). I was given direct KLINK and then fly the approach (no Procedure Turn) so I (re)programmed the GPS KLINK-KORF. Upon reaching KLINK I turned in on the approach; but I neglected to switch the CDI. However; I thought that I had done so; and so followed the indications on NAV 1; which had me on course laterally (which was correct) and also vertically (which; of course; was not). I also overlooked the fact that the GS (not received) flag was showing on NAV 1.Basically; I just saw what I expected to see. I will have to be more diligent in the future. Upon my return home later that afternoon; when I had to fly an ILS (ceiling 800 overcast); I selected the ILS on both NAV 1 and NAV 2; and got identical needle movement; so there had been nothing wrong with NAV 2 and the ILS signal for the approach at ORF must just have been weak. By the time of the flight home; I had figured out what had happened; and was trying not only to be extra careful on the approach; but also deliberately comparing the two ILS signals to see whether I had a problem with my instruments.
BE35 pilot reports descending early on the ILS RWY 23 into ORF due to improper setup of Nav panel. ATC issues a low altitude alert and the reporter eventually climbs back to 1;600 feet from 800 feet.