B737 Next Generation Undifferentiated
Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 393; Flight Crew Type 2500
Situational Awareness
ATC Issue All Types; Aircraft Equipment Problem Less Severe
Flight Crew Executed Go Around / Missed Approach
Aircraft; Human Factors
As we were being vectored for landing on 05R; the Controller kept us high (RDU had switched runways from 23L to 05R). While tracking the 05R LOC; we were about to capture the 05R glideslope from above at approximately 6.5 to 7 miles from the runway and suddenly the glideslope needle jumped full scale up to the 'top of the case'. This gave the illusion of the aircraft suddenly diving for the ground. I immediately pulled up and abandoned the approach. The Controller vectored us back around for another approach for 05R. The subsequent approach and landing was uneventful.This is the second time in as many months that I have experienced this glideslope anomaly. The last one was in MKE at night. This glideslope anomaly is something that has just started happening. In over 43 years of flying; with many thousands of IMC approaches; this has never been a problem until now.
On arrival and approach to RDU; we configured early to get down to glidepath. Once on glidepath; we noticed that the flight director went blank with the course deviation indicator and glideslope indicator precessing dramatically from top to bottom (and left to right) of HSI. Getting confused as to what was happening; we abandoned the approach and were vectored around the pattern for an uneventful approach and landing.The Captain explained that this was the second time in the last month that he has seen this anomaly. He suggested we write this report to bring light to a possible adverse condition with the flight director system.
B737-700 flight crew reported executing a go-around on approach to RDU after experiencing a glide slope anomaly.