Boeing 727-251 and Boeing EC-135 incident near Casper, Wyoming, June 2, 1987
On June 2, 1987 at about 4:12 pm local time, 2 aircraft, Boeing 727-251 (N297US) and Boeing EC-135 (USAF), were involved in the same incident near Casper, Wyoming. No one was hurt; 72 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The NTSB has not yet published a probable cause for this incident. Investigations usually take one to two years; this page updates when the final report is released.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 2, 1987 · about 4:12 pm local time
- Place
- Casper, Wyoming
- Type
- Incident
- Injuries
- No one was hurt; 72 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Boeing 727-251 · all 727-251s on the register
- Registration
- N297US · no longer on the register · serial 21789
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · scheduled airline rules (Part 121)
- Aircraft 2
- Boeing EC-135
- Registration
- USAF · no longer on the register
- Damage
- Not recorded
- Flight
- Flight of an unrecorded kind · military rules
The NTSB's narrative for the Boeing 727-251 final · quoted from the NTSB record
BOEING 727 (NORTHWEST FLT 354) & USAF EC-135 (SLUM 51) WERE INVOLVED IN A NR COLLISION AT FL 330. THE MISHAP OCCURRED ASFLT 354 WAS ENE BND ON J-158 & SLUM 51 WAS FLYING ON A RADIAL-DISTANCE (R/D) FLT PLN, FLYING BTN R/D PTS SOUTH OF J-158.AS SLUM 51 APCHD ITS MOST WESTERN PT, THE CREW REQD A RGT TURN TO A R/D PT THAT WAS NOT THE NEXT LISTED PT ON THEIR FLT PLN. THE TRAINEE CTLR (T/C) DIDN'T REALIZE SLUM 51 WAS REQG A ROUTE CHG, BUT THOUGHT THE FLT WANTED TO TURN BACK EAST TOTHE NEXT FILED R/D PT WITH A RGT TURN (INSTEAD OF A L TURN AS PREVIOUSLY DONE). THE T/C REPLIED, 'UNABLE RGT TURN, MAKE A LEFT TURN.' THE INSTRUCTOR HEARD THE REQ, BUT THOUGHT THE T/C'S REPLY WAS DISAPPROVAL OF A ROUTE CHG. AS THE CTLRS TURNED THEIR ATTN TO OTR (HVY/COMPLEX) TRAFFIC, SLUM 51 CONTD A 270 DEG L TURN (TO NORTH) & CONVERGED WITH FLT 354. THE 9020 (PRIMARY) COMPUTER WAS INOP; THE DARC (BACKUP) COMPUTER HAD NO CAPABILITY OF DISPLAYING PROJECTED ROUTES OR PROVID-ING CONFLICT ALERT. NO FLOW CTL RESTRICTIONS WERE IN EFFECT TO RDC THE AMOUNT OF TRAFFIC.
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 Boeing EC-135 final · quoted from the NTSB record
BOEING 727 (NORTHWEST FLT 354) & USAF EC-135 (SLUM 51) WERE INVOLVED IN A NR COLLISION AT FL 330. THE MISHAP OCCURRED ASFLT 354 WAS ENE BND ON J-158 & SLUM 51 WAS FLYING ON A RADIAL-DISTANCE (R/D) FLT PLN, FLYING BTN R/D PTS SOUTH OF J-158.AS SLUM 51 APCHD ITS MOST WESTERN PT, THE CREW REQD A RGT TURN TO A R/D PT THAT WAS NOT THE NEXT LISTED PT ON THEIR FLT PLN. THE TRAINEE CTLR (T/C) DIDN'T REALIZE SLUM 51 WAS REQG A ROUTE CHG, BUT THOUGHT THE FLT WANTED TO TURN BACK EAST TOTHE NEXT FILED R/D PT WITH A RGT TURN (INSTEAD OF A L TURN AS PREVIOUSLY DONE). THE T/C REPLIED, 'UNABLE RGT TURN, MAKE A LEFT TURN.' THE INSTRUCTOR HEARD THE REQ, BUT THOUGHT THE T/C'S REPLY WAS DISAPPROVAL OF A ROUTE CHG. AS THE CTLRS TURNED THEIR ATTN TO OTR (HVY/COMPLEX) TRAFFIC, SLUM 51 CONTD A 270 DEG L TURN (TO NORTH) & CONVERGED WITH FLT 354. THE 9020 (PRIMARY) COMPUTER WAS INOP; THE DARC (BACKUP) COMPUTER HAD NO CAPABILITY OF DISPLAYING PROJECTED ROUTES OR PROVID-ING CONFLICT ALERT. NO FLOW CTL RESTRICTIONS WERE IN EFFECT TO RDC THE AMOUNT OF TRAFFIC.
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 Boeing 727-251 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 12,230 hours in all; 10,000 in this make and model
- Medical certificate: Class 1 (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 191,500 lb
- Seats: 134
- Landing gear: retractable
- Engine: P&W JT8D (turbofan); 0 hours total
The flight
- Departed from: SFO San Francisco CA
- Destination: MSP Minneapolis MN
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Weather at the time
- Light: daylight
- Sky: clear
- Temperature: 0°F (-18°C), dew point 0°F (-18°C)
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 6 | |||
| Passengers | 54 |
The factual record for the Boeing EC-135 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot, military
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 6,000 hours in all; 3,300 in this make and model
- Medical certificate: Unknown (valid medical--no waivers/lim.)
- Seat: left
The aircraft
- Last inspection: inspection type not recorded
- Maximum gross weight: 325,000 lb
- Landing gear: retractable
- Engine: P&W J-57 (turbojet); 0 hours total
The flight
- Departed from: RCA Rapid City SD at 1:05 pm
- Flight plan: IFR
- Runway 0
- A second pilot was aboard
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 4 | |||
| Passengers | 8 |
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.