Cessna A150L and Grumman 164B mid-air collision near Ephrata, Washington, August 1, 1993
On August 1, 1993 at about 4:50 pm local time, 2 aircraft, Cessna A150L (N5958J) and Grumman 164B (N8407K), were involved in a mid-air collision near Ephrata, Washington (Ephrata airport). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
INADEQUATE VISUAL LOOKOUT BY BOTH PILOTS, RESULTING IN THEIR FAILURE TO SEE-AND-AVOID EACH OTHER'S AIRCRAFT. A FACTOR RELATED TO THE ACCIDENT WAS: FAILURE OF THE GRUMMAN 164B PILOT TO ADEQUATELY MONITOR THE UNICOM FREQUENCY.
INADEQUATE VISUAL LOOKOUT BY BOTH PILOTS, RESULTING IN THEIR FAILURE TO SEE-AND-AVOID EACH OTHER'S AIRCRAFT. A FACTOR RELATED TO THE ACCIDENT WAS: FAILURE OF THE GRUMMAN 164B PILOT TO ADEQUATELY MONITOR THE UNICOM FREQUENCY.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 1, 1993 · about 4:50 pm local time
- Place
- Ephrata, Washington · Ephrata · map
- Type
- Accident · mid-air collision
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Cessna A150L · all A150Ls on the register
- Registration
- N5958J · registry record · serial A1500258
- Damage
- Destroyed
- Flight
- Instructional flight · general aviation rules (Part 91)
- Aircraft 2
- Grumman 164B
- Registration
- N8407K · no longer on the register · serial 689B
- Damage
- Destroyed
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative for the Cessna A150L final · quoted from the NTSB record
A MID-AIR COLLISION OCCURRED AT AN ALTITUDE OF 50 TO 75 FT OVER THE THRESHOLD OF RUNWAY 2, WHICH INVOLVED A CESSNA 150, N5958J, & A GRUMMAN 164B, N8407K. THE CESSNA PILOT WAS A SOLO STUDENT, PRACTICING TOUCH-AND-GO LANDINGS. HE WAS ON FINAL APPROACH TO RUNWAY 2. THE GRUMMAN PILOT HAD ENTERED THE AIRPORT ENVIRONMENT FROM THE NORTH & WAS SPRAYING A HERBICIDE ON THE EDGE OF THE RUNWAYS FOR WEED CONTROL. WHILE IN THE PATTERN, THE STUDENT SAW THE GRUMMAN & THOUGHT IT WAS DEPARTING FROM RUNWAY 11. AFTER THAT, HE DID NOT SEE THE GRUMMAN. THE GRUMMAN PILOT STATED THAT AS HE APPROACHED THE AIRPORT, HE ANNOUNCED THAT HE WOULD BE SPRAYING THE WEST SIDE OF RUNWAY 20 & ON RUNWAY 11. HOWEVER, NEITHER THE STUDENT NOR 2 WITNESSES, WHO WERE MONITORING THE UNICOM FREQUENCY, HEARD THE GRUMMAN PILOT ANNOUNCE HIS INTENTIONS. THE GRUMMAN PILOT SAID THAT HE NEITHER SAW NOR HEARD THE CESSNA IN THE TRAFFIC PATTERN, BUT THE 2 WITNESSES VERIFIED THAT THE STUDENT HAD ANNOUNCED HIS POSITION AROUND THE PATTERN.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Grumman 164B final · quoted from the NTSB record
A MID-AIR COLLISION OCCURRED AT AN ALTITUDE OF 50 TO 75 FT OVER THE THRESHOLD OF RUNWAY 2, WHICH INVOLVED A CESSNA 150, N5958J, & A GRUMMAN 164B, N8407K. THE CESSNA PILOT WAS A SOLO STUDENT, PRACTICING TOUCH-AND-GO LANDINGS. HE WAS ON FINAL APPROACH TO RUNWAY 2. THE GRUMMAN PILOT HAD ENTERED THE AIRPORT ENVIRONMENT FROM THE NORTH & WAS SPRAYING A HERBICIDE ON THE EDGE OF THE RUNWAYS FOR WEED CONTROL. WHILE IN THE PATTERN, THE STUDENT SAW THE GRUMMAN & THOUGHT IT WAS DEPARTING FROM RUNWAY 11. AFTER THAT, HE DID NOT SEE THE GRUMMAN. THE GRUMMAN PILOT STATED THAT AS HE APPROACHED THE AIRPORT, HE ANNOUNCED THAT HE WOULD BE SPRAYING THE WEST SIDE OF RUNWAY 20 & ON RUNWAY 11. HOWEVER, NEITHER THE STUDENT NOR 2 WITNESSES, WHO WERE MONITORING THE UNICOM FREQUENCY, HEARD THE GRUMMAN PILOT ANNOUNCE HIS INTENTIONS. THE GRUMMAN PILOT SAID THAT HE NEITHER SAW NOR HEARD THE CESSNA IN THE TRAFFIC PATTERN, BUT THE 2 WITNESSES VERIFIED THAT THE STUDENT HAD ANNOUNCED HIS POSITION AROUND THE PATTERN.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the Cessna A150L from the NTSB's investigation tables, in plain English
Pilot
- Certificate: student
- Flight time: 17 hours in all; 17 in this make and model; 17 in the last 90 days; 17 in the last 30 days; 2 as pilot in command
- Medical certificate: Class 3 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 2,470 hours
- Last inspection: 100-hour inspection, November 24, 1992; 45 hours since
- Maximum gross weight: 1,600 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental O-200 (piston); 0 hours total
- Fire on the ground
- Operator: Civil Air Patrol, INC
The flight
- Departed from: EPH at 4:30 pm
- Destination: EPH
- Flight plan: none
- Runway 2, 6,699 ft by 150 ft
Weather at the time
- Light: daylight
- Wind: from 010° at 7 knots
- Visibility: 20 statute miles
- Sky: clear
- Temperature: 77°F (25°C), dew point 45°F (7°C)
- Altimeter: 30.00 inHg
- Observation at 4:51 pm from EPH
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
The factual record for the Grumman 164B from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane; instrument: helicopter; rotorcraft: helicopter
- Flight time: 17,500 hours in all; 10,000 in this make and model; 200 in the last 90 days; 75 in the last 30 days
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: ctr
The aircraft
- Last inspection: 100-hour inspection, July 10, 1993; 70 hours since
- Maximum gross weight: 5,600 lb
- Seats: 1
- Landing gear: fixed
- Engine: P&W R-1340-AN2 (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: EPH at 4:15 pm
- Destination: EPH
- Flight plan: none
- Runway 0
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.