Aviation Accident Summaries

Aviation Accident Summary WPR19TA110

St. Helena, CA, USA

Aircraft #1


Kubicek BB100


The pilot departed on a routine flight, after reviewing the weather forecast, including wind and temperatures aloft. Additionally, he received weather information from his boss, who used pilot balloons to find prevailing winds, that the winds were favorable to their southern direction of flight. After an uneventful departure, the balloon started to drift northwest, but the accident pilot rapidly climbed to 3,000 ft at which point the balloon was diverted by winds from the northwest. According to passengers, the balloon pilot did not provide any safety instructions or emergency procedures prior to departure, nor did he during the accident flight until his first landing attempt. After about 1 hour and 45 minutes of flight the pilot decided to land on a small plot of terrain as he was unfamiliar with the terrain east of their position. The pilot did not recite any safety instructions prior to the balloon's impact with the ground, but instead he informed the passengers to brace for impact. The balloon impacted a blackberry bush, which likely absorbed some of the vertical energy. After a brief ascent, the balloon impacted the ground hard a second time and came to rest. One passenger was seriously injured. It is likely that the pilot balloons released by the company owner to find the prevailing winds indicated desirable winds at lower altitudes. As the wind was not forecasted to be in a southeast direction below 3,000 ft. The balloon pilot's encounter with unforecasted wind conditions likely resulted in his decision to land in unsuitable terrain, which resulted in a hard landing and serious injuries. Further, although he did deliver some safety instructions during the flight, several passengers were unclear on the emergency procedure and the pilot did not clarify his instructions when prompted. Thus, the pilot's lack of a thorough and clear safety briefing may have prevented some of the passengers from securing themselves properly for the abnormal landing.

Factual Information

On April 14, 2019, about 1123 Pacific daylight time, a Balony Kubicek SPOL SR BB100Z hot air balloon, N355WC, sustained minor damage when it was involved in an accident near St. Helena, California. The pilot and 12 passengers were not injured. Two passengers received minor injuries and one passenger was seriously injured. The balloon was operated under the provisions of Title 14 Code of Federal Regulations Part 91 as a sightseeing flight. According to the pilot, his weather planning did not show any restrictions for their intended flight and the owner of the balloon company had used pilot balloons to determine that the wind was traveling in their preferred direction of flight. The pilot said he provided a safety briefing to his passengers and then launched uneventfully from a location about 4 nm north of Santa Rosa Airport (STS), Santa Rosa, California. A second balloon departed behind him several minutes later. After departure, the wind carried the balloon to the northwest and then rapidly to the southeast over hills and variable terrain. The pilot of the second balloon reported that he had aborted his flight about 30 minutes after departure once he observed the accident balloon being forced east by prevailing winds. The accident pilot climbed and descended to find more favorable wind conditions but was unsuccessful. Approximately 55 minutes into the flight, the pilot identified a possible landing site ahead of him. He advised the passengers to secure themselves and bend their knees. As he descended, he determined that the site was unsuitable for landing and aborted that attempt. About 30 minutes later he located a small plot on the backside of a hill to land in. He entered a course reversal at 1,000 ft and notified the passengers that he would be crossing a power pole and descending quickly. According to the pilot, he also recommunicated the safety instructions from earlier and then yelled "this is going to be a hard landing!" The balloon descended over the power lines and a residence, but the wind started blowing the balloon to the north toward a vineyard. The pilot intentionally descended the balloon onto a blackberry bush to land. After the basket made contact, it got stuck in the bush and the momentum from the balloon canopy pulled the basket forward and caused it to swing like a pendulum. The basket impacted the ground at an angle and came to rest. One passenger was seriously injured during the landing. Several passengers provided accounts of the accident flight. The flight was delayed about 2 hours due to fog. When the fog conditions lifted, passengers were loaded into each of two hot air balloons. Some passengers recalled that the accident pilot delivered an introduction for securing their cellular telephones/smart phones and embarking/disembarking procedures but did not provide any safety instructions or emergency procedures. Two passengers perceived the accident pilot to be in a rush as he previously mentioned that winds can change rapidly. He had not communicated to the passengers that they were on an incorrect flight path but did inform them that he had 3 hours of fuel onboard. Prior to the first landing attempt, some of the passengers recalled that the pilot advised them to bend their knees and secure themselves with the basket handles during landing. One hour and 30 minutes into the flight they traversed a mountain. The pilot informed some of the passengers that he would prefer to land soon as he is unfamiliar with the area. Suddenly and without warning, the accident pilot advised the passengers to brace for landing. Some passengers were confused by his previous safety instructions, which indicated that they should be facing the direction of landing instead of bracing themselves against the partitions. The balloon descended rapidly and impacted a blackberry bush and ascended briefly before it impacted the ground again and came to rest. Weather Planning According to the owner of the company who departed in a separate balloon at the same time as the accident flight, he obtained his ground wind data from a website managed by the National Oceanic and Atmospheric Administration. The local wind information he provided to the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) began at 0955 and terminated at 1225. According to the data, at 0955 the wind was at 3 knots on a southern heading. For the subsequent 15 minutes, the wind directions alternated between north and south every 5 minutes with wind speeds between calm and 3 knots. From 1020 on, the wind direction remained southerly between 3 and 7 knots until the time of the accident, with the exception of 1205 when the wind was calm and in a northern direction. The accident pilot reported that his morning preflight included a review of the STS automated weather observing system, which indicated calm surface winds and some fog. Wind and temperatures aloft forecast for San Francisco, California showed wind from 310° at 14 knots for 3,000 ft; however, he had planned to maintain an approximate altitude of 500 ft on the day of the accident. When he arrived at the departure point, the company owner communicated to the pilot that he had floated two pilot balloons, a small meteorological balloon used to track air currents, down the valley, which indicated to the owner that the wind favored their intended route of flight to the south. Weather Study An NTSB weather study used meteorological aviation routine weather reports (METARs), terminal aerodrome forecasts (TAFs), wind and temperatures aloft forecasts, and numerical model sounding to capture the forecast and actual wind conditions between the time of the balloon's departure and the accident. A review of METARs for STS about 20 minutes after the balloon's departure show wind from 170° true at 3 knots. The wind continued from the southeast, between 140° and 160° through the accident flight. A TAF issued at 0917 and valid for a 24-hour period beginning at 0900 showed wind from the southwest until the evening when the wind was forecasted to shift to a northwestern wind. The wind and temperature aloft forecast valid from 0700 to 1400 for San Francisco, California showed wind at 3,000 ft from 310° true at 14 kts and from 280° at 12 kts. A forecast valid for the same time period for Sacramento, California showed wind at 3,000 ft from 200° at 12 kts and 6,000 ft from 260° at 11 kts. A high-resolution rapid refresh numerical model sounding for the flight path at 1200 from the surface to 10,000 ft indicated wind from 225° to 300° at 10 to 18 kts below 3,000 ft. Safety Discussion with Operator During a subsequent conversation with the balloon operator, the NTSB IIC reported that passengers had not received any safety instructions or emergency procedures prior to the accident flight. The operator explained that they did not perform a safety briefing prior to each flight but agreed to hold consistent briefings. Further, he elected to implement a new policy to ensure that all passengers receive a safety briefing prior to each flight. Additionally, the IIC inquired about the operator's accident plan, a policy that includes an action plan for pilots to contact emergency response and support passengers in the event of an incident or other emergency. The operator reported that they did not have one in place but agreed to develop one immediately for future flights.

Probable Cause and Findings

The balloon pilot's encounter with unforecasted wind, which resulted in his decision to land in unsuitable terrain and a subsequent hard landing. Contributing to the severity of passenger injury was the pilot’s failure to provide a proper safety briefing.


Source: NTSB Aviation Accident Database

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