Hiller UH-12E accident near Mack, Colorado, May 13, 1989
On May 13, 1989 at about 1:48 pm local time, a Hiller UH-12E (helicopter), registered N5594N, was substantially damaged in an accident near Mack, Colorado. It was an aerial application (crop spraying) flight under agricultural flying rules (Part 137). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
THE PILOT'S FAILURE TO MAINTAIN PROPER ALTITUDE DURING A SWATH RUN.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- May 13, 1989 · about 1:48 pm local time
- Place
- Mack, Colorado · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Hiller UH-12E · all UH-12Es on the register
- Registration
- N5594N · no longer on the register · serial 1453
- Damage
- Substantial damage
- Flight
- Aerial application (crop spraying) flight · agricultural flying rules (Part 137)
The NTSB's narrative final · quoted from the NTSB record
THE PILOT STATED THAT DURING A SWATH RUN HE LET THE HELICOPTER GET TOO LOW AND THE SKIDS CONTACTED THE ALFALFA CROP FOLLOWED BY THE SPRAY APPARATUS. THE PILOT WAS UNABLE TO GAIN ALTITUDE AND THE HELICOPTER CONTINUED TO DESCEND INTO THE GROUND AND ROLLED OVER. AN EYE-WITNESSES CONCURRED WITH THE PILOT'S STATEMENT BUT DECLINED TO GIVE A WRITTEN STATEMENT.
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 from the NTSB's investigation tables, in plain English
Pilot
- Certificate: commercial pilot
- Ratings: single-engine land; rotorcraft: helicopter
- Flight time: 298 hours in all; 8 in the last 90 days; 4 in the last 30 days
- Medical certificate: Class 2 (valid medical--no waivers/lim.)
- Seat: ctr
The aircraft
- Airframe total time: 4,313 hours
- Last inspection: annual inspection, January 22, 1989; 6 hours since
- Maximum gross weight: 2,850 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming VO-540-C2A (piston); 0 hours total
The flight
- Departed from: Mack CO
- Flight plan: none
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 310° at 3 knots
- Visibility: 9 statute miles
- Sky: broken clouds at 9,000 ft; scat at 6,000 ft
- Temperature: 48°F (9°C), dew point 36°F (2°C)
- Altimeter: 29.00 inHg
- Observation at 1:52 pm from GJT, 20 miles away
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.
Other NTSB records under N5594N the same tail number, which may have belonged to a different aircraft at the time
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.