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A md-83 digital flight guidance system (DFGS) circuit breaker opened after takeoff; IMC near convective weather. With all DFGS system indications frozen and contending with uncommanded yaw oscillations; the crew declared an emergency and diverted to a nearby VMC airport where an emergency landing was completed after a go-around for unsafe gear.
| Attributes | |
| ACN | 1172204 |
| Time | |
| Date | 201405 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZZZ.Airport |
| State Reference | US |
| Environment | |
| Flight Conditions | IMC |
| Light | Dusk |
| Aircraft 1 | |
| Make Model Name | MD-83 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Component | |
| Aircraft Component | Flight Dynamics Navigation and Safety |
| Person 1 | |
| Function | Pilot Not Flying Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Person 2 | |
| Function | Flight Attendant In Charge Flight Attendant (On Duty) |
| Qualification | Flight Attendant Current |
| Experience | Flight Attendant Airline Total 1 Flight Attendant Number Of Acft Qualified On 5 Flight Attendant Total 5 Flight Attendant Type 90 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Conflict Ground Conflict Less Severe Inflight Event / Encounter Weather / Turbulence |
Narrative:
During climb; both the autopilot and autothrottles disconnected. We were IMC in rain showers. Convective weather was in the area. The aircraft began un-commanded yaw oscillations. Most [of the] digital flight guidance system (DFGS) froze at the settings; which were displayed at the time of disconnect. Only the course setting and VHF navigation settings were operational. Circuit breaker C-18 was popped. We declared an emergency and requested vectors to the nearest suitable airport with VFR conditions. Considering weather and controllability issues; neither of us felt return to ZZZ was prudent. ATC gave us vectors to ZZZ1. We executed the following checklists: airplane oscillating or displaced in yaw; rudder control manual; emergency landing; mechanical checklist; normal checklist landing gear handle down with one or more red lights illuminated. We briefed the flight attendants. We also contacted dispatch and made PA to the passengers. On final; we had 3 red gear indication lights. The nose gear indication pin indicated normal extension. We executed a go-around in order to run the QRH gear extension checklist. During the go-around; the tower advised us that the gear appeared down. After running the QRH; gear indications became green. We landed xxr and stopped on the runway. Air field rescue and fire fighters (arff) inspected the plane. Company mechanics stowed the gear doors; pinned the gear and towed us to the terminal. I made several PA's to the passengers to advise them of the aircraft status while we were having the mechanics prepare to tow the plane. On a separate note; a business jet appeared to make an approach and go around to our runway xxr while we were disabled on the runway. As we were getting the gear pinned; airport operations one spotted the jet and radioed the tower. The tower responded that the jet was going around. The jet indicated 100 feet above the runway on our TCAS as he flew past us.
Original NASA ASRS Text
Title: A MD-83 Digital Flight Guidance System (DFGS) circuit breaker opened after takeoff; IMC near convective weather. With all DFGS system indications frozen and contending with uncommanded yaw oscillations; the crew declared an emergency and diverted to a nearby VMC airport where an emergency landing was completed after a go-around for unsafe gear.
Narrative: During climb; both the autopilot and autothrottles disconnected. We were IMC in rain showers. Convective weather was in the area. The aircraft began un-commanded yaw oscillations. Most [of the] Digital Flight Guidance System (DFGS) froze at the settings; which were displayed at the time of disconnect. Only the course setting and VHF NAV settings were operational. Circuit breaker C-18 was popped. We declared an emergency and requested vectors to the nearest suitable airport with VFR conditions. Considering weather and controllability issues; neither of us felt return to ZZZ was prudent. ATC gave us vectors to ZZZ1. We executed the following checklists: AIRPLANE OSCILLATING OR DISPLACED IN YAW; RUDDER CONTROL MANUAL; EMERGENCY LANDING; MECHANICAL CHECKLIST; NORMAL CHECKLIST LANDING GEAR HANDLE DOWN WITH ONE OR MORE RED LIGHTS ILLUMINATED. We briefed the flight attendants. We also contacted Dispatch and made PA to the passengers. On final; we had 3 red gear indication lights. The nose gear indication pin indicated normal extension. We executed a go-around in order to run the QRH GEAR EXTENSION checklist. During the go-around; the Tower advised us that the gear appeared down. After running the QRH; gear indications became green. We landed XXR and stopped on the runway. Air Field Rescue and Fire Fighters (ARFF) inspected the plane. Company mechanics stowed the gear doors; pinned the gear and towed us to the terminal. I made several PA's to the passengers to advise them of the aircraft status while we were having the mechanics prepare to tow the plane. On a separate note; a business jet appeared to make an approach and go around to our Runway XXR while we were disabled on the runway. As we were getting the gear pinned; Airport OPS ONE spotted the jet and radioed the Tower. The Tower responded that the jet was going around. The jet indicated 100 feet above the runway on our TCAS as he flew past us.
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.