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B738 first officer reported that a false glideslope capture resulted in an unstabilized approach; followed by a go-around.
| Attributes | |
| ACN | 1710286 |
| Time | |
| Date | 201912 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | SMF.Tower |
| State Reference | CA |
| Environment | |
| Flight Conditions | IMC |
| Aircraft 1 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Final Approach |
| Flight Plan | IFR |
| Person 1 | |
| Function | Pilot Not Flying First Officer |
| Qualification | Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument |
| Experience | Flight Crew Last 90 Days 171 Flight Crew Total 2505 Flight Crew Type 2505 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Altitude Undershoot Deviation - Procedural Published Material / Policy Deviation - Speed All Types Inflight Event / Encounter Unstabilized Approach |
Narrative:
On descent and approach into smf we were descending via the SLMMR3; I was the pilot monitoring. At approximately pozur we were cleared for the ILS runway 16L once reaching tenco. We set 1;900 ft. In the MCP window for levey and we were in LNAV/VNAV. Approximately at dirbe we were fully configured target speed was set and we were slowing. We were on the VNAV descent path and shortly after passing dirbe VOR/localizer and glideslope captured; tdze was set in the MCP window. I was changing to the tower frequency and when I looked up the airspeed was about vref and the trend was still slowing rapidly. I called airspeed and reached up to advance the throttles about the same time the captain did. I looked to the attitude indicator and the aircraft was pitching about 15-20 degrees up. I called to push the nose down and at the same time pushed forward on the control column. Again VOR/localizer and GS were both captured and the auto throttles were on. The captain recovered and we were only between 1/2 dot and 1 dot above glideslope and still outside the FAF; but at this point continuing the approach did not seem like a good idea so I called for a go-around. We were still outside levey and above 2;000 ft. And tower assigned us runway heading and continue descent and maintain 2;000 ft. We were then vectored around for another approach and landed. This could have been a false glideslope capture but we were on the VNAV descent path and on or slightly below the glideslope indicator.
Original NASA ASRS Text
Title: B738 First Officer reported that a false glideslope capture resulted in an unstabilized approach; followed by a go-around.
Narrative: On descent and approach into SMF we were descending VIA the SLMMR3; I was the Pilot Monitoring. At approximately POZUR we were cleared for the ILS Runway 16L once reaching TENCO. We set 1;900 ft. in the MCP window for LEVEY and we were in LNAV/VNAV. Approximately at DIRBE we were fully configured target speed was set and we were slowing. We were on the VNAV descent path and shortly after passing DIRBE VOR/LOC and glideslope captured; TDZE was set in the MCP window. I was changing to the tower frequency and when I looked up the airspeed was about Vref and the trend was still slowing rapidly. I called airspeed and reached up to advance the throttles about the same time the Captain did. I looked to the attitude indicator and the aircraft was pitching about 15-20 degrees up. I called to push the nose down and at the same time pushed forward on the control column. Again VOR/LOC and GS were both captured and the auto throttles were on. The Captain recovered and we were only between 1/2 dot and 1 dot above glideslope and still outside the FAF; but at this point continuing the approach did not seem like a good idea so I called for a go-around. We were still outside LEVEY and above 2;000 ft. and Tower assigned us runway heading and continue descent and maintain 2;000 ft. We were then vectored around for another approach and landed. This could have been a false glideslope capture but we were on the VNAV descent path and on or slightly below the glideslope indicator.
Data retrieved from NASA's ASRS site 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.