unk Boeing 777 - 236 incident
Boeing 777 - 236 · Incident: near midair/TCAS alert/loss of separation en route
From Shemya, AK to Shemya, AK
Narrative check · The NTSB narrative appears to contradict this record's departure or destination. Values are shown as recorded, not corrected; compare with the narrative.
Event
- NTSB case
- OPS14IA011
- 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
- Unknown
Boeing 777 - 236
- Aircraft type
- Boeing 777
- 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
- N773AN
- Operator
- unk
- Onboard fatalities
- Unknown
- Route Possible conflict
- From Shemya, AKTo Shemya, 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 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 · change of cruise level
- 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
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
A loss of required separation occurred near Shemya, Alaska, between a Boeing 777-200 en route to Shanghai Pudong International Airport, Shanghai, China, and a Boeing 747-400 en route to Ted Stevens Anchorage International Airport, Anchorage, Alaska. There was no damage to either aircraft, and no injuries were sustained by the passengers or crewmembers.
The flight crew of the Boeing 777 requested to climb from flight level (FL) 360 to FL 370. Given the Boeing 777's position at the time, the requested climb would have conflicted with two other airplanes that were traveling at FL 370 but in the opposite direction. The air traffic controller identified the potential conflict between the Boeing 777 and the first airplane, but he did not identify the conflict between the Boeing 777 and the second airplane, the Boeing 747. The controller instructed the flight crew of the Boeing 777 to remain at FL 360 until they passed the first airplane and then to climb to FL 370. The flight crew of the Boeing 777 acknowledged and complied with the clearance, which resulted in a loss of required separation with the Boeing 747. Both flight crews received and responded to resolution advisories from their onboard traffic alert and collision avoidance systems after the controller issued the climb clearance. The Federal Aviation Administration (FAA) estimated that the minimum separation between the two aircraft was 1.04 miles laterally and 900 ft vertically.
Typically, two types of automated conflict detection were available to controllers in the Shemya radar coverage area: a "conflict probe" that provided controllers with extended warning time for future conflicts and a short-term conflict alert system that looked about 2 minutes ahead to detect conflicts between radar-observed aircraft. However, the FAA had intentionally disabled the extended conflict probe in the Shemya radar coverage area because of unresolved performance issues, and the only automated conflict detection assistance available to the controllers in this area was the short-term conflict alert system; this removed a layer of backup to controller judgment and reduced the overall safety of flight operations in this area. Postincident corrective actions resulted in the extended conflict probe being returned to service. If the extended conflict probe had been available at the time of the incident, it is likely that it would have detected the conflict and alerted the controller about it before he issued the incorrect clearance and that no loss of separation would have occurred.
Probable cause
The air traffic controller’s failure to identify a conflict between two aircraft and to issue an adequate clearance, which resulted in a loss of required separation. Contributing to the incident was the Federal Aviation Administration’s failure to provide controllers adequate automated conflict detection assistance, which removed a layer of backup to controller judgment and reduced the overall level of safety.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record OPS14IA011
- Event ID
- 20140819X44937
- Case number
- OPS14IA011
- 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, coordinates, damage. Values present in the bulk record are kept.
- The date is the local date; the NTSB stores the UTC date 2014-08-16.
- API snapshot SHA-256: fe613976d487ecf5fa6ce2041f1e0a3371b777ab8e8d597c463a9bf78a1f5a14; retrieved 2026-09-16T01:39:32.593Z.