Alaska Airlines Flight 601
McDonnell Douglas MD-82 · Incident: near collision between aircraft en route
From Reno Tahoe International Airport (RNO) to Seattle–Tacoma International Airport (SEA)
Event
- NTSB case
- LAX94IA331
- 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
- Incident
- 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
- 0
- 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
- Visual Meteorological Cond
McDonnell Douglas MD-82
- Aircraft type
- McDonnell Douglas MD-82
- 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
- N954AS
- Operator
- Alaska Airlines
- Onboard fatalities
- Unknown
- Route
- From Reno Tahoe International Airport (RNO)To Seattle–Tacoma International Airport (SEA), Seattle, WA
- 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
- En route · climb to cruise
- First occurrenceThe 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
- Near collision between aircraft
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- None
Cause areas
- Atc personnel(supervisor) › Air/ground communications, not maintained
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
ALASKA AIRLINES FLIGHT 601 (ASA601), N954AS, WAS ON A STANDARD INSTRUMENT DEPARTURE WHEN IT NEARLY COLLIDED WITH A MOONEY M20C, N91Y. THE MOONEY WAS TRANSITING THE RENO AIRSPACE AT 12,500 FEET MSL AND HAD JUST BEEN HANDED OFF FROM THE TRACON DEPARTURE CONTROLLER TO THE ARRIVAL CONTROLLER. THE LOCAL CONTROLLER DID NOT INFORM ASA601 TO CONTACT DEPARTURE CONTROL AFTER TAKEOFF. DURING ASA601'S INITIAL CLIMB, THE DEPARTURE CONTROLLER/AREA MANAGER LEFT HIS POSITION TO ANSWER A PHONE CALL FROM A FACILITY TECHNICIAN TO DISCUSS TRACON BUSINESS. AT THE SAME TIME, THE ARRIVAL CONTROLLER WAS TELLING THE MOONEY TO CHANGE TRANSPONDER CODES IN PREPARATION FOR A HANDOFF TO CENTER; AT THAT TIME, THERE WAS SOME CONFUSION BETWEEN THE MOONEY PILOT AND THE CONTROLLER ABOUT THE TRANSPONDER CODE. THE ARRIVAL CONTROLLER SAID HE DID NOT SEE THE DATA BLOCK FOR ASA601 BECAUSE HIS ATTENTION WAS DIVERTED TO THE MOONEY. THE CHANGING OF THE TRANSPONDER CODE AND THE MOONEY'S INTERMITTENT MODE C TRANSPONDER KEPT ASA601'S TCAS SYSTEM FROM ACQUIRING THE MOONEY. AFTER HIS PHONE CALL, THE DEPARTURE CONTROLLER TRIED TO CALL ASA601, BUT WITHOUT SUCCESS. HE THEN CALLED THE LOCAL CONTROLLER AND WAS INFORMED OF THE NEAR COLLISION.
Probable cause
FAILURE OF THE AREA SUPERVISOR/DEPARTURE CONTROLLER (SUPVR/CTLR) TO STAY AT HIS RADAR POSITION AND ENSURE THAT REQUIRED COMMUNICATIONS WERE MAINTAINED. FACTORS RELATED TO THE INCIDENT WERE: FAILURE OF THE LOCAL TOWER CONTROLLER INSTRUCT THE FLIGHTCREW OF ASA601 (N954AS) TO CONTACT DEPARTURE CONTROL, FAILURE OF THE ARRIVAL/DEPARTURE CONTROLLERS TO ISSUE TRAFFIC ADVISORIES, SUPERVISOR/DEPARTURE CONTROLLER'S DIVERTED ATTENTION, AND INTERMITTENT OPERATION OF THE TRANSPONDER IN THE MOONEY, THUS NOT ACTIVATING THE TCAS OF ASA601.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record LAX94IA331
- Event ID
- 20001206X02067
- Case number
- LAX94IA331
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
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: investigation status, damage. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 11f4cd03707949a9f5e0652cdb75b683c659312ba24ee57788eed962e493ec1a; retrieved 2026-09-18T18:09:36.783Z.