Individually Owned: 150,657
Corporate Owned: 137,281
Lawton-Fort Sill Regional Airport
Aircraft Accident/Incident Report
Lawton, Oklahoma 73501
Sunday, February 22, 1998 10:21 CST
NTSB Narrative Summary Released at Completion of Accident
During cruise flight, the flight crew reported smelling an odor similar to burning/smoldering electrical equipment and noticed that the landing gear control circuit breaker had popped. The flight crew consulted the company's Quick Reference Handbook (QRH). The QRH addressed hydraulic problems and failed to discuss possible electrical problems related to the operation of the landing gear. The company's maintenance facility was appraised of the situation; however, the maintenance person on duty was not able to assist the flight crew. Three tower fly-bys were made. The flight attendant and tower personnel reported that the landing gear appeared to be down and the gear doors were closed. The flight crew elected to land with the light on the gear handle indicating an 'in-transit' condition and the two main landing gear indicators in the 'unsafe' condition. The left main landing gear on the twin-engine transport category airplane collapsed during the landing roll. Examination revealed that the weight-on-wheels relay, which is located in the avionics bay directly under the captain's station, shorted, and as a result, the landing gear control circuit breaker popped. The electrical short was attributed to the spill of a soda can on the flight deck on a previous flight. The investigation revealed that the cockpit floor was not carpeted or sealed to prevent fluids/moisture from seeping into the electrical compartment beneath the cockpit floor. A review of the emergency extension system for the airplane revealed that the landing gear could have been extended if the fight crew had pulled the emergency extension handle.
NTSB Probable Cause Narrative
the collapse of the left main landing gear during landing roll as result of a shorted weight-on-wheels relay. Contributing factors were the insufficient information available to the flight crew in the company's quick reference handbook (QRH), and the manufacturer's inadequate protection of the weight-on-wheels relay from moisture.
Event Information
| Type of Event | Incident |
| Event Date | 2/22/1998 |
| Event Day of the Week | Sunday |
| Time of Event | 1021 |
| Event Time Zone | Central Standard Time |
| Event City | LAWTON |
| Event State | OKLAHOMA |
| Event Country | -- |
| Zipcode of the event site | 73501 |
| Event Date Year | 1998 |
| Event Date Month | 2 |
| MidAir Collision Indicator | No |
| On Ground Collision occurred ? | No |
| Event Location Latitude | -- |
| Event Location Longitude | -- |
| Event Location Airport | LAWTON-FORT SILL REGIONAL |
| Event Location Nearest Airport ID | LAW |
| Indicates whether the acc/inc occurred off or on an airport | On Airport |
| Distance from airport in statute miles | -- |
| Degrees magnetic from airport | -- |
| Airport Elevation | 1110 |
| Weather Briefing Completeness | Not pertinent |
| Investigator's weather source | Weather Observation Facility |
| Time of the weather observation | 1029 Central Standard Time |
| Direction of event from weather observation facility (degrees) | 90 |
| Weather Observation Facility ID | LAW |
| Elevation of weather observation facility | 1110 |
| Distance of event from weather observation facility (units?) | 1 |
| Time Zone of the weather observation | CST |
| Lighting Conditions | Day |
| Lowest Ceiling Height | 2600 |
| Lowest Non-Ceiling Height | 1600 |
| Sky/Lowest/Cloud Conditions | Scattered |
| Sky Condition for Lowest Ceiling | Broken |
| Visibility Runway Visual Range (Feet) | 0 |
| Visibility Runway Visual Value (Statute Miles) | 0 |
| Visibility (Statute Miles) | 10 |
| Air Temperature at event time (in degrees celsius) | 11 |
| Dew Point at event time (in degress fahrenheit) | 7 |
| Wind Direction (degrees magnetic) | 100 |
| Variable Wind Indicator | Unknown |
| Wind Speed (knots) | 10 |
| Wind Velocity Indicator | Unknown |
| Wind Gust Indicator | Not Gusting |
| Wind Gust (knots) | 0 |
| Altimeter Setting at event time (in. Hg) | 29 |
| Density Altitude (feet) | -- |
| Intensity of Precipitation | Unknown |
| METAR weather report | -- |
| Event Highest Injury | None |
| On Ground, Fatal Injuries | 0 |
| On Ground, Minor Injuries | 0 |
| On Ground, Serious Injuries | 0 |
| Injury Total Fatal | -- |
| Injury Total Minor | -- |
| Injury Total None | 6 |
| Injury Total Serious | -- |
| Injury Total All | -- |
| Investigating Agency | NTSB |
| NTSB Docket Number (internal use) | 5035 |
| NTSB Notification Source | -- |
| NTSB Notification Date | Feb 22 1998 12:00AM |
| NTSB Notification Time | 1049 |
| Fiche Number and/or location -used to find docket information | IMAGE |
| Date of most recent change to record | May 19 2001 4:45AM |
| User who most recently changed record | dbo |
| Basic weather conditions | Visual Meteorological Cond |
| FAA District Office | -- |
Aircraft Involved |
|
|---|---|
Aircraft #1 |
|
| Aircraft Registration Number | N396AE |
| NTSB Number | FTW98IA130 |
| Missing Aircraft Indicator | N |
| Federal Aviation Reg. Part | Part 121: Air Carrier |
| Type of Flight Plan filed | IFR |
| Flight plan Was Activated? | -- |
| Damage | Minor |
| Aircraft Fire | None |
| Aircraft Explosion | None |
| Aircraft Manufacturer's Full Name | Saab-Scania AB (Saab) |
| Aircraft Model | 340B |
| Aircraft Series Identifier | 340B |
| Aircraft Serial Number | 340B-396 |
| Certified Max Gross Weight | 29000 |
| Aircraft Category | Airplane |
| Aircraft Registration Class | U.S. Registered/U.S. Soil |
| Aircraft is a homebuilt? | No |
| Flight Crew Seats | -- |
| Cabin Crew Seats | -- |
| Passenger Seats | -- |
| Total number of seats on the aircraft | 37 |
| Number of Engines | 2 |
| Fixed gear or retractable gear | Retractable |
| Aircraft, Type of Last Inspection | Continuous Airworthiness |
| Date of Last Inspection | Dec 27 1997 12:00AM |
| Airframe hours since last inspection | 334 |
| Airframe Hours | 3579 |
| ELT Installed | Yes |
| ELT Activated | No |
| ELT Aided Location of Event Site | Unknown |
| ELT Type | -- |
| Aircraft Owner Name | FIRST SECURITY BANK NA |
| Aircraft Owner Street Address | 79 SOUTH MAIN STREET |
| Aircraft Owner City | SALT LAKE CITY |
| Aircraft Owner State | UT |
| Aircraft Owner Country | |
| Aircraft Owner Zipcode | 84111 |
| Operator is an individual? | -- |
| Operator Name | SIMMONS AIRLINES |
| Operator Same as Owner? | No |
| Operator Is Doing Business As | -- |
| Operator Address Same as Owner? | No |
| Operator Street Address | P.O. BOX 612527, MD 1200 |
| Operator City | DFW AIRPORT |
| Operator State | TX |
| Operator Country | |
| Operator Zip code | 75261 |
| Operator Code | SIMA |
| Owner has at least one certificate | Yes - certificate holder |
| Other Operator of large aircraft? | No |
| Certified for Part 133 or 137 Operation | Unknown |
| Operator Certificate Number | -- |
| Indicates whether an air carrier operation was scheduled or not | Scheduled |
| Indicates Domestic or International Flight | Domestic |
| Operator carrying Pax/Cargo/Mail | Passenger Only |
| Type of Flying (Per_Bus / Primary) | Unknown |
| Second Pilot on Board | Yes |
| Departure Point Same as Event | No |
| Departure Airport Code | DFW |
| Departure City | DFW AIRPORT |
| Departure State | TX |
| Departure Country | |
| Departure Time | 919 |
| Departure Time Zone | CST |
| Destination Same as Local Flt | crash at destination city |
| Destination Airport Code | LAW |
| Destination City | |
| Destination State | |
| Destination Country | |
| Specific Phase of Flight | Cruise |
| Report sent to ICAO? | -- |
| Evacuation occurred | -- |
| Date of most recent change to record | May 19 2001 4:07AM |
| User who most recently changed record | dbo |
| Since inspection or accident | -- |
| Event Location Runway Number and Location | 35 |
| Runway Length | 8599 |
| Runway Width | 150 |
| Sight Seeing flight | No |
| Air Medical Flight | No |
| Medical Flight | -- |