Boeing 737-2H4 incident near Lincoln, Nebraska, January 8, 2008
On January 8, 2008 at about 11:45 pm local time, a Boeing 737-2H4, registered N733TW, was involved in an incident during taxi (from runway) near Lincoln, Nebraska (Lincoln Muni airport). It was flown under scheduled airline rules (Part 121). No one was hurt; 38 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The improper installation of the swivel valve fittings by the operator's mechanic leading to the total loss of both hydraulic systems. Contributing to the incident were the swivel valves leaking and the total failure of the hydraulic system.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- January 8, 2008 · about 11:45 pm local time
- Place
- Lincoln, Nebraska · Lincoln Muni · map
- Type
- Incident
- Injuries
- No one was hurt; 38 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Boeing 737-2H4 · all 737-2H4s on the register
- Registration
- N733TW · no longer on the register · serial 22732
- Damage
- Not recorded
- Flight
- Flight · scheduled airline rules (Part 121)
The NTSB's narrative final · quoted from the NTSB record
Two days before the incident flight, the airplane was placed in maintenance for a "[Left/Hand Main Landing Gear] swivel valve leaking." The corrective action was accomplished by one of the operator's mechanics. The mechanic reportedly removed both the swivel valves on the left main landing gear. The aft swivel valve was removed and replaced with a new valve. The forward valve was removed and reinstalled. That valve was checked for leaks and the airplane was returned to service prior to the incident flight. The airplane, on a non-scheduled domestic passenger flight, was taxiing after landing, exited the taxiway, and became stuck in snow and mud despite the pilot's attempts to maintain directional control. The captain reported a total loss of all hydraulic systems. The airplane's maintenance manual 32-41-61 contained a warning that stated, "WARNING: MAKE SURE THAT THE SWIVEL JOINT AND HYDRAULIC LINES ARE ORIENTED AS SHOWN ... . THE HYDRAULIC LINE TO THE BRAKE ASSEMBLY MUST BE CONNECTED TO THE SWIVEL HOUSING AND THE HYDRAULIC LINE FROM THE ANTI-SKID VALVE TO THE SWIVEL FITTING AS SHOWN ... . IF THE ASSEMBLY OF THE SWIVEL AND THE HYDRAULIC LINES ARE ROTATED 180 DEGREES, THE HYDRAULIC LINES CAN BE CONNECTED BUT THE SWIVEL WILL NOT OPERATE. THIS CAN CAUSE THE HYDRAULIC LINES TO BREAK DURING EXTENSION AND RETRACTION AND CAUSE THE BRAKES PRESSURE TO BE LOST." Examination of the swivel valves after the incident revealed that both valves were not installed as depicted in the maintenance manual.
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
What happened, in order
- Sys/Comp malf/fail (non-power) during taxi (from runway) defining event
- Collision with terrain or object (not controlled flight into terrain) during taxi (from runway)
The NTSB's findings
- factor Aircraft › Aircraft systems › Hydraulic power system › (general) › Failure
- Environmental issues › Physical environment › Terrain › Wet/muddy › Not specified
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Maintenance personnel
- Environmental issues › Physical environment › Terrain › Snowy/icy › Not specified
Pilot
- Certificate: airline transport pilot, commercial pilot, flight engineer
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 15,000 as pilot in command
- Medical certificate: Class 1
- Seat: left
- Injury: no injuries
Co-pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land
- Flight time: 3,380 in this make and model; 15,000 as pilot in command
- Medical certificate: Class 1
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 71,959 hours
- Last inspection: continuous airworthiness programme, November 1, 2007
- Maximum gross weight: 116,000 lb
- Seats: 63
- Landing gear: retractable
- Engine 1: Pratt & Whitney JT8D-17 (turbofan); 0 hours total
- Engine 2: Pratt & Whitney JT8D-17 (turbofan); 0 hours total
- Operator: Ameristar Air Cargo, Inc.
The flight
- Departed from: AUS Austin TX at 3:59 pm
- Destination: Lincoln NE
- Flight plan: IFR
- Runway 36, 12,901 ft by 200 ft
- A second pilot was aboard
Weather at the time
- Light: night
- Wind: from 280° at 6 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 37°F (3°C), dew point 23°F (-5°C)
- Altimeter: 30.05 inHg
- Observation at 10:54 pm from LNK
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Cabi | 4 | |||
| Flight crew | 2 | |||
| Passengers | 32 |
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.