Summary
- Severe turbulence on an Allegiant Air flight in July left six people injured, two of them seriously.
- The National Transportation Safety Board (NTSB) released its final report, stating that it was unlikely for the flight crew to have been aware they were entering a turbulent area.
- Satellite radar imagery showed that low-level winds resulted in convective buildup where the plane was flying.
Severe turbulence on an Allegiant Air flight in July left six people injured, up from previous reports suggesting that only 4 people suffered minor injuries. The most recent development comes from the National Transportation Safety Board (NTSB), which released its final report and investigation into the probable cause on Friday.
Two of the six people onboard sustained serious injuries because the Airbus A320 reportedly encountered unsettled air at around 13,000 feet amid its final descent into St. Petersburg-Clearwater International Airport (PIE) in Florida. In its report, the NTSB said it was unlikely for the flight crew to have been aware that they were entering a turbulent area.
Details of the incident
Allegiant flight 227 (AAY227) originated from Asheville Regional Airport in North Carolina on July 12, 2023, with 179 passengers and 6 crew members onboard. The captain was a check pilot, and the primary officer was the pilot accountable for the aircraft, N249NV, throughout the turbulence encounter, based on the NTSB’s final report and investigation docket obtained by The Aviation Herald.
Photo: Markus Mainka | Shutterstock
During its descent, heavy to moderate rain was about 45 miles within the direction of the aircraft’s flight path, which prompted Air Traffic Control (ATC) to instruct the crew to make adjustments. The crew was informed to descend to 19,000 feet but deviate to the correct of its course once under 26,000 feet and proceed on to its subsequent flight path intersection. At around 23,000 feet, ATC reportedly instructed the pilots to cross the intersection at 13,000 feet and a speed of 250 knots.
Short but severe
Nevertheless, the pilots said the ATC’s instruction was given late, causing the aircraft to be nearly 5,000 feet high. Speed brakes were deployed, and the autopilot was turned off to permit the aircraft to satisfy its altitude and speed expectations. Based on the report, the seatbelt sign was on, however the 4 flight attendants onboard weren’t yet notified of the aircraft’s final descent. The plane then traveled through a cloud, where the incident occurred.
Photo: ZikG | Shutterstock
“As AAY227 approached its level-off altitude, the flight crewmembers observed a small cumulus buildup at an altitude of about 13,000 ft that was unavoidable. Based on the primary officer, the clouds weren’t dark and looked no different than the clouds that the airplane had previously flown through. Because the airplane entered the clouds, it encountered some minor expected jolts, and just before exiting, a severe jolt of turbulence occurred that lasted about 1.5 seconds.”
The probable cause
Sattelite radar imagery indicated that several low-level winds emerged near the incident site, leading to convective buildup where the plane was flying. The National Weather Service reportedly issued information for the world about quarter-hour before the encounter and implied however the NTSB report explained how the pilots could have remained unaware of the unsettled atmosphere.
“The Tampa WSR-88D detected a developing cell within the immediate vicinity of the turbulence event with echoes between 15 – 45 dBZ, nevertheless, cockpit weather radar doesn’t typically pick up echoes lower than 20 dBZ. Subsequently, it’s unlikely the flight crew were aware that they were getting into a bigger area of convection that included higher intensity echoes situated east of their flight path and encountered moderate or greater convectively induced turbulence (CIT) throughout the clouds.”
Following the incident, the captain was informed of multiple injuries. Two of the 4 flight attendants were reportedly conducting seatbelt compliance checks throughout the turbulence encounter and were thrown up into the cabin, hitting the ceiling, after which slammed back all the way down to the ground. Nevertheless, only one in all those flight attendants received serious injuries.
The opposite serious injury was a flight attendant within the aft galley of the aircraft. Each received medical attention once the plane landed at PIE. 4 passengers had minor injuries, while the opposite two flight attendants weren’t injured.