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B737-800 flight crew reported their approach became unstabilized when VNAV was mistakenly de-selected.
| Attributes | |
| ACN | 1291417 |
| Time | |
| Date | 201508 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | JFK.Airport |
| State Reference | NY |
| Aircraft 1 | |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Initial Approach |
| Flight Plan | IFR |
| Person 1 | |
| Function | Pilot Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Events | |
| Anomaly | Deviation - Procedural Published Material / Policy Inflight Event / Encounter Unstabilized Approach |
Narrative:
On approach to runway 13L; as PF; I lost VNAV guidance because I mistakenly hit the VNAV button. After multiple attempts I could not get VNAV to re-engage. Since we were on a visual approach; I elected to continue without it. Meanwhile; while trying to slow below 170 KIAS to approach speed; the throttles kept pushing themselves up. As I tried to manage the airspeed; the throttles were hampering my effort to reduce airspeed. I elected to disengage the autothrottles and continued the approach. During this time we had become high on the approach. I pitched over to get back on a visual glide path. At some point on the approach; we got a 'sink rate; sink rate' warning. I do not recall if we were below 500 feet in which case; we should have gone around. We determined we were in a safe position to land so we continued the approach and landed uneventfully.PF should coordinate with PNF to coordinate any MCP/FMC changes so as not to distract from flying.pm should be ready to be able to offer back-up visual guidance by use of V/south mode when primary means is lost. If we thought we were close to 500 feet when we hear the 'sink rate; sink rate' warning; we should have done the conservative thing and gone around.
Original NASA ASRS Text
Title: B737-800 flight crew reported their approach became unstabilized when VNAV was mistakenly de-selected.
Narrative: On approach to Runway 13L; as PF; I lost VNAV guidance because I mistakenly hit the VNAV button. After multiple attempts I could not get VNAV to re-engage. Since we were on a visual approach; I elected to continue without it. Meanwhile; while trying to slow below 170 KIAS to approach speed; the throttles kept pushing themselves up. As I tried to manage the airspeed; the throttles were hampering my effort to reduce airspeed. I elected to disengage the autothrottles and continued the approach. During this time we had become high on the approach. I pitched over to get back on a visual glide path. At some point on the approach; we got a 'sink rate; sink rate' warning. I do not recall if we were below 500 feet in which case; we should have gone around. We determined we were in a safe position to land so we continued the approach and landed uneventfully.PF should coordinate with PNF to coordinate any MCP/FMC changes so as not to distract from flying.PM should be ready to be able to offer back-up visual guidance by use of V/S mode when primary means is lost. If we thought we were close to 500 feet when we hear the 'sink rate; sink rate' warning; we should have done the conservative thing and gone around.
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.