SkyWest Airlines Flight 4543
Bombardier Inc CL-600-2C10 · Accident: ground handling event during pushback
From Salt Lake City International Airport (SLC) to OKC Will Rogers World Airport (OKC)
Event
- NTSB case
- WPR11LA058
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 0 · all aircraft and ground
- Ground fatalities
- Unknown
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- Airline
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Instrument Meteorological Cond
Bombardier Inc CL-600-2C10
- Aircraft type
- Bombardier CL-600
- Category
- Airplane
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N614SK
- Operator
- SkyWest Airlines
- Onboard fatalities
- Unknown
- Route
- From Salt Lake City International Airport (SLC), Salt Lake City, UTTo OKC Will Rogers World Airport (OKC), Oklahoma City, OK
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 121: Air Carrier
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- Pushback/towing
- Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Ground handling event
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Personnel issues › Task performance
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
The airplane was operating 2 hours behind schedule and had been dispatched with its auxiliary power unit (APU) inoperative, a condition that was permissible based on the approved Minimum Equipment List. The ramp area was covered in snow and ice, and it was snowing during aircraft loading and the subsequent pushback attempt. The captain started both engines while the airplane was at the gate, utilizing an external air-start cart in lieu of the APU. The captain stated that he started both engines due to a concern that, by starting one engine only, he would encounter control problems taxiing in the slippery conditions. He recognized that he could also have attempted to start the second engine in the alleyway after pushback using a cross-bleed engine start, but was concerned that attempting such a start would require increased engine thrust on the operating engine and could be disruptive to ground personnel and other traffic within the alleyway.
During pushback, the tug was unable to gain enough traction to move the airplane and was subsequently replaced with a larger tug. The larger tug was able to push back the airplane; however, a short time later the thrust from the airplane's engines, which were running at idle, exceeded the traction available to the tug. The captain, seated in the left seat, experienced a sensation of unusual movement as the airplane began to overpower the tug, and he asked the tug driver if the driver still had control of the airplane. The tug driver confirmed that he had control; however, the airplane subsequently moved forward while still attached to the tug, which rotated to the right striking the airplane's fuselage.
According to ground personnel and flight crew guidance, if the ramp surface conditions were such that adequate traction was not available, engine start should have been delayed until the pushback was complete. However, an engine start was required prior to pushback due to the inoperative APU. No guidance existed for either the flight or ground crew regarding pushback procedures in low traction ramp conditions with an inoperative APU.
Probable cause
The tug driver’s loss of airplane control during pushback due to a loss of traction in slippery conditions on the ramp. Contributing to the accident was the ground crews’ and airline operators’ inadequate guidance with regard to pushback procedures during low ground traction conditions with an inoperative airplane auxiliary power unit.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record WPR11LA058
- Event ID
- 20101124X20432
- Case number
- WPR11LA058
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: local date, investigation status. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2010-11-24.
- API snapshot SHA-256: 6aaee47dde4edd0c5a83a601d55677261de9e26b6cc883de6e725f1a4cfc3002; retrieved 2026-09-15T15:34:59.889Z.