This is preliminary information, subject to change, and may contain errors. Any errors in this report will be corrected when the final report has been completed.
https://registry.faa.gov/AircraftInquiry/Search/NNumberResult?nNumberTxt=N138DD
- History of Flight:
On January 18, 2026, at about 1502 local time, a Bell 206L-1 LongRanger II, N138DD, registered to Dalton Aviation LLC out of Bluffdale, UT, sustained substantial damage when it was involved in an accident near Timber Lakes, Utah. The pilot sustained serious injuries, and three passengers sustained minor injuries. The helicopter was being operated as Title 14 Code of Federal Regulations Part 91 personal flight.
According to preliminary Automatic Dependent Surveillance – Broadcast (ADS-B) data, at 1451 LT, the helicopter was observed departing an open area near Independence, Utah, before proceeding northeast towards an altitude of 9,400 ft. At about 1500 LT, the helicopter entered a left turn and started hovering over the accident site. Towards the end of the track, the helicopter entered a secondary left turn and slowed down to about 14 knots groundspeed before it disappeared from coverage (figure 1).
Two online videos captured the accident sequence, the helicopter appeared to hover over snowy mountainous wooded terrain when it entered a right yaw, which was not corrected and developed into an uncontrollable spin. The helicopter descended into trees before coming to rest. Neither video showed the actual approach to the accident area.
In the second video, a group of people (one of them who captured the first video) were observed next to a stationary Robinson helicopter and a group of cars. It is most likely that the Bell was coming in for a landing before the accident sequence (figure 2).
- Pilot Information:
Unknown.
- Aircraft Information:
The accident helicopter, serial number 45199, was manufactured in 1979. It was powered by an Allison Model 250 engine.
- Wreckage and Impact Information:
The helicopter clipped several trees before coming to rest on its right side. The helicopter was mostly intact, but sustained substantial damage. There was no post crash fire. The estimated accident site elevation was 9400 ft.
- Weather:
Based on ADS-B data, accident site elevation, and weather conditions at the time, the calculated density altitude was around 10,000 ft.
(1) METARs:
METAR KU69 182135Z AUTO 10007KT 10SM CLR 04/M12 A3018 RMK A01
METAR KU69 182155Z AUTO 13007KT 10SM CLR 04/M12 A3017 RMK A01
METAR KU69 182215Z AUTO 12007KT 10SM CLR 04/M12 A3017 RMK A01
METAR KU69 182235Z AUTO 12006KT 10SM CLR 04/M12 A3017 RMK A01
METAR KHCR 182135Z AUTO 00000KT 10SM CLR 07/M09 A3018 RMK AO2 T00661089 $
METAR KHCR 182155Z AUTO 00000KT 10SM CLR 08/M09 A3017 RMK AO2 T00791087 $
METAR KHCR 182215Z AUTO 00000KT 10SM CLR 08/M08 A3017 RMK AO2 T00761083 $
METAR KHCR 182235Z AUTO 00000KT 10SM CLR 08/M09 A3016 RMK AO2 T00761085 $
(2) Area Forecast Discussion:
Area Forecast Discussion National Weather Service Salt Lake City UT 313 PM MST Sun Jan 18 2026 .KEY MESSAGES... - Valley inversions look to weaken through tomorrow with some redevelopment possible by Tuesday afternoon. - Precipitation chances appear to have trended later in time, with our next best shot around the Friday-Sunday timeframe. The majority of 12z ensemble members support this, with roughly ~50% favoring northern UT. && .DISCUSSION... Looking at the 12z upper air sounding from KSLC, it appears that a warm layer aloft remains, though it has lifted somewhat higher as the boundary layer deepens. As such, we can expect another day of improved air quality and visibilities across much of northern UT today. Additionally, this will encourage mixing yielding drier air at the surface today compared to some of the more humid conditions the past few days which yielded low stratus and instances of patchy fog. Currently, a longwave trough is slowly progressing east with its axis positioned across the Southeastern U.S. while ridging to our southwest gradually regresses further south. This will continue ushering in northwesterly flow on the backside of the aforementioned large upper trough through at least Wednesday. Within this flow, embedded perturbations will clip northern UT each day enabling some colder air aloft with enhanced flow, serving to cool down and mix above the boundary layer and perhaps lifting inversions higher as a result. A weak frontal boundary may pass through northern UT Tuesday afternoon, though confidence has decreased somewhat regarding the overall magnitude and if it will lift the inversion further. As such, haze (at or below 6SM visibilities) will remain in the forecast Tuesday afternoon through Thursday evening. Forecast confidence regarding our next shot at precipitation has unfortunately all but improved as we approach the weekend. While the general consensus among ensemble members supports troughing across the Western U.S., the timing and positioning have diverged quite substantially. Looking at current ensembles, it appears we have returned to early season form with southern UT being favored due to a southern storm track, though much of UT and SW WY can expect to see at least a trace of precipitation. For solutions favoring northern UT, roughly ~50% of ensemble guidance supports more than a trace of precipitation from the Fri-Sun timeframe. The silver lining with this set up, at least, is that enough cold air should advect into the area to scour inversions and improve air quality as we enter the weekend. .AVIATION...KSLC...VFR conditions are expected to prevail through the forecast period under mostly clear skies. There is around a 20% chance or lower that visibilities will dip into MVFR or below late tonight into Monday morning. Light north to northwesterly winds are expected to continue through Monday afternoon, with periods of light and variable winds. .REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected to prevail across all terminals through the forecast period, although there is around a 20% chance that visibilities will dip into MVFR or lower late tonight into Monday morning mainly near the Idaho border. Winds will remain generally light and terrain driven through much of the period, with light northerly winds becoming more widespread across northern and western Utah through the evening hours.
- Additional Information:
Loss of Tail Rotor Effectiveness
The Federal Aviation Administration has published the Helicopter Flying Handbook FAA-H-8083-21A (2012).This handbook discusses loss of tail rotor effectiveness and states in part:
Loss of tail rotor effectiveness (LTE) or an unanticipated yaw is defined as an uncommanded, rapid yaw towards the advancing blade which does not subside of its own accord. It can result in the loss of the aircraft if left unchecked. It is very important for pilots to understand that LTE is caused by an aerodynamic interaction between the main rotor and tail rotor and not caused from a mechanical failure. Some helicopter types are more likely to encounter LTE due to the normal certification thrust produced by having a tail rotor that, although meeting certification standards, is not always able to produce the additional thrust demanded by the pilot.
LTE is an aerodynamic condition and is the result of a control margin deficiency in the tail rotor. It can affect all single rotor helicopters that utilize a tail rotor of some design. The design of main and tail rotor blades and the tail boom assembly can affect the characteristics and susceptibility of LTE but will not nullify the phenomenon entirely.
No comments:
Post a Comment