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Warbelows Air Ventures Flight 401

14 Jun 2011 · Fairbanks, AK, United States

Beech 1900C and Era Aviation Piper PA-31-350 · Incident: near midair/TCAS alert/loss of separation on approach

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Event

NTSB case
OPS11IA653
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
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
Charter & commuter
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Not recorded

Aircraft 1 · Beech 1900C

Aircraft type
Beechcraft 1900
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
N121WV
Onboard fatalities
Unknown
Route
From not recordedTo Fairbanks, AK
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 135: Air Taxi & Commuter
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
Approach · VFR pattern downwind
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
Near midair/TCAS alert/loss of separation
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
None

Aircraft 2 · Piper PA-31-350

Aircraft type
Piper PA-31
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
N4112K
Operator
Era Aviation
Onboard fatalities
Unknown
Route
From Fairbanks International Airport (FAI), Fairbanks, AKTo not recorded
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 135: Air Taxi & Commuter
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
Initial climb
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
Near midair/TCAS alert/loss of separation
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

  • Personnel issues › Action/decision
  • Personnel issues › Task performance

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

An air traffic control operational error and near midair collision occurred between a Raytheon Beech 1900 and a Piper Navajo about 3.5 miles west of the airport. The Beech 1900 was northeast bound toward the airport descending to enter the traffic pattern for runway 20L, while the Piper had just departed from runway 20R and was climbing on a westbound heading. Both airplanes were operating under visual flight rules at the time of the incident, and were receiving air traffic control services from a tower air traffic controller. There were no reports of injuries or damage to either airplane.

The local controller, who had only been certified on the position for 5 weeks, stated that she was trying to establish vertical separation between the two airplanes by restricting the departing Navajo to remain at or below 2,000 feet. The Beech was still on the approach controller's frequency, so the local controller was not aware of what instructions had been issued to the pilot. The approach controller mistakenly believed that the Beech was in communication with the local controller. Neither the local controller nor the controller-in-charge, who was responsible for monitoring the operation and assisting the local controller, initiated any coordination with the approach controller to resolve the conflict.

NTSB review of local procedures and directives found that there was a misunderstanding of required procedures and controller responsibilities for operations in Terminal Radar Service Areas, including separation standards and procedures for transfer of communications between controllers.

Probable cause

Inadequate air traffic control actions that failed to establish and maintain required separation between the two airplanes. Contributing to the incident was inexperience on the part of the local controller, inadequate oversight by the tower controller-in-charge, and deficient facility procedures and training.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record OPS11IA653
Event ID
20110615X31614
Case number
OPS11IA653
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: 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: aa5de4842532d1e91272aae4c4f4e11fa18c932f8ad89eb62baa965f2bb1b133; retrieved 2026-09-13T18:19:20.296Z.