On the morning of January 26, 2024, a Beechcraft Model 99, N53RP, went down due to unknown circumstances shortly after departing Manchester Boston Regional Airport (KMHT) at 7:10 a.m. EST (1210Z). The pilot survived the accident and was taken to a local hospital in critical condition. As shown in FlightAware, the aircraft's track was very erratic for 17 minutes and lost communication with air traffic control during most of this time. The altitude was erratic as well and the airplane never climbed higher than 5,100 feet according to the FlightAware track log.
The analysis to follow is preliminary and may contain errors and omissions. Nonetheless, a nasty icing environment was present at the time the aircraft departed, although icing may not have been a factor. News reports suggest that the National Transportation Safety Board said the left cockpit door/hatch was found in a yard about 6 miles north of the crash site.
The routine surface observation just before departure includes calm winds, broken ceiling at 900 feet, visibility of 4 statute miles in moderate rain and a surface temperature of +2°C. The flight category of the airport was IFR at this time due to the 900-foot ceiling.
METAR KMHT 261153Z 00000KT 4SM RA BR BKN009 BKN014 OVC021 02/00 A3016 RMK AO2 SLP231
At 1248Z, the tower issued the following special observation (SPECI) primarily due to the airport becoming MVFR with a broken ceiling at 1,000 feet. This may also have been issued due to the aircraft mishap near the airport.
KMHT 261248Z 36004KT 3SM RA BR BKN010 OVC024 02/00 A3020 RMK AO2 TWR VIS 4 P0017=
Given the time of day, there were not many pilot weather reports for icing in the immediate area. The first was a report for light rime ice at 3,000 feet at 1305Z northwest of KMHT.
Another report at 1432Z just to the west of the airport was for light clear ice at 4,000 feet.
However, there was a significant icing risk aloft. At 1200Z, there was a deep saturated atmosphere at the airport that supported the moderate rain observation.
A closer view reveals that there were three freezing levels at 800 feet, 5,000 feet and 9,500 feet. This is very common for a freezing rain aloft scenario. It is likely snow was falling through this deep saturated atmosphere and fully melted between the warm nose from 9,500 feet to 5,000 feet with the maximum temperature of +2°C. The depth and temperature of this melting layer was sufficient to fully melt the snow. Below 5,000 feet, the temperature ranged from 0°C to -4°C. The moderate rain fell through this subfreezing layer as freezing rain aloft.
There were no SIGMETs in the area at this time. Manchester was within a G-AIRMET for moderate ice from the surface through FL230.
The icing severity at 3,000 feet showed the potential for heavy icing in the accident area at 1200Z.
Moreover, in line with the sounding analysis shown above, the icing diagnostics (CIP/FIP) showed a clear indication of SLD potential aloft. The image below is an overlay of SLD potential (red) with the icing severity (blue). Darker shades of red suggest that both heavy ice (shown above) with SLD potential exist.
One thing worth noting is that a situation like this can be very misleading since there wasn't officially any forecast or observation for freezing rain since the temperature at the surface was warmer than 0°C. But this does not negate a freezing rain hazard aloft.
KMHT 261120Z 2612/2712 04003KT 5SM RA BR BKN015 OVC025
FM261400 04005KT 2SM -DZ BR OVC004
FM262100 03005KT 1/2SM FG OVC003=
For a good summary of the ATC comms during this time, see this excellent video from VASAviation. In the communication with ATC, the pilot's communication is very garbled, but the pilot does say that he has an emergency and wants to return to the field for the ILS to 35. This may have been due to some other issue that was not directly related to weather, and therefore, may not have been a cause of this accident. The NTSB will put out a preliminary report shortly that may shed some light on this.
Most pilots are weatherwise, but some are otherwise™
Dr. Scott Dennstaedt
Weather Systems Engineer
Founder, EZWxBrief™
CFI & former NWS meteorologist
