Fokker F28 MK0100 incident near Atlanta, Georgia, November 11, 1990
On November 11, 1990 at about 11:10 pm local time, a Fokker F28 MK0100, registered N850US, was involved in an incident near Atlanta, Georgia. It was a flight of an unrecorded kind under scheduled airline rules (Part 121). No one was hurt; 75 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
FROZEN MOISTURE IN THE STABILIZER ACTUATOR HYDRAULIC SERVO VALVE WHICH RESULTED IN REDUCED MOVEMENT OF THE SERVO VALVE AND LIMITED ITS ABILITY TO RESPOND TO FLIGHT CONTROL INPUTS. THE LACK OF RESPONSE FROM THE SERVO VALVE RESULTED IN THE JAMMED STABILIZER MESSAGE. A FACTOR WAS THE INADEQUATE DESIGN OF THE SERVO VALVE WHICH PRECLUDED MOISTURE DRAINAGE.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- November 11, 1990 · about 11:10 pm local time
- Place
- Atlanta, Georgia
- Type
- Incident
- Injuries
- No one was hurt; 75 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Fokker F28 MK0100
- Registration
- N850US · no longer on the register · serial 11276
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
DURING DESCENT THE AFCAS STABILIZER TRIM & AUTOPILOT DISENGAGED. BOTH WERE RESET WITH A 2ND DISENGAGEMENT. NOSE DOWN CONTROL PRESSURES WERE ENCOUNTERED & THE FLT CREW ATTEMPTED TO USE MANUAL TRIM, FOLLOWED BY A JAMMED STABILIZER MASTER WARNING. AFCAS STABILIZER TRIM WAS LEFT OFF IAW ABNORMAL PROCEDURES. FDR DATA SHOWED THE STAB THEN CREEPED TO A FULL ACFT NOSE DOWN POSITION & HYD PRES TO THE STAB ACTUATOR WAS AUTOMATICALLY REMOVED, PER DESIGN. SUBSEQUENT TESTING OF THE HORIZONTAL STABILIZER CONTROL UNIT ASSEMBLY SHOWED THAT, AFTER SPRAYING THE SERVO VALVE WITH WATER AND COLD SOAKING, ICE WOULD FORM INSIDE THE END CAP AND A JAMMED SERVO VALVE CONDITION WOULD OCCUR. THE END CAP AND SPRING EXHIBITED SUBSTANTIAL RUST CORROSION. CREW MOVEMENT OF THE MANUAL TRIM RESULTED IN THE JAMMED STAB WARNING.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; instrument: airplane
- Flight time: 15,127 hours in all
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,674 hours
- Last inspection: continuous airworthiness programme, October 10, 1990; 147 hours since
- Maximum gross weight: 98,100 lb
- Seats: 109
- Landing gear: retractable
- Engine: Rolls-Royce TAY650715 (turbojet); 0 hours total
The flight
- Departed from: PHL Philadelphia PA at 9:32 pm
- Destination: ATL Atlanta GA
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: dusk
- Wind: from 300° at 4 knots
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 61°F (16°C), dew point 39°F (4°C)
- Altimeter: 30.00 inHg
- Observation at 10:50 pm from ATL
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 5 | |||
| Passengers | 70 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.