The National Transportation Safety Board ( NTSB ) has published its final report about a turbulence-related incident involving a JetBlue Airbus A320 flying from Ecuador to Fort Lauderdale, Florida, the United States, resulting in nine injuries onboard the aircraft.
Entering turbulence without warnings
The NTSB's report detailed that the incident happened on September 25, 2023, and involved a JetBlue Airbus A320, registered as N569JB. The 2003 built-aircraft remains in active service with the airline.
The captain told the investigators that the initial climb and cruise at 34,000 feet (10,363 meters) progressed normally. Flight conditions were dark and clear, and the pilots observed no convective activity.
According to both pilots, the aircraft's radar was on, it had WiFi connectivity, and they were constantly updating radar images on their Jeppeson FliteDeck (JeppFD) and Weather Services International (WSI) software.
"The first officer stated there was significant precipitation and storms to the north of their location in the area near Cuba. As the flight proceeded north, the crew noted an additional area of weather between Jamaica and Cuba that required weather deviations."
In response, both pilots changed weather ranges on their radar displays multiple times to maintain their situational awareness about the weather in the area. At 03:35:47 local time (UTC -5), the weather radar was in 'weather and turbulence mode' on both pilots' navigational displays. The captain's radar had a range of 160 nautical miles (296.3 kilometers), while the first officer's had 320 NMI (592.6 km) of range.
"Autopilot number 2 and the auto thrust were engaged, with Mach target of 0.8 selected, and the seatbelt sign was illuminated."
At 03:36:20, the A320 encountered turbulence, with the pilots remarking that they entered an area of severe turbulence and extreme precipitation without any warnings or returns of their weather radar.
Related Several Hospitalized After JetBlue Airbus A320 Hit Severe Turbulence
Seven passengers and one crew member were transported to hospital.
Posts 10 Climbing 1,000 ft in less than a minute
"The FDR [flight data recorder - ed. note] data indicated that the airplane varied in pitch angle between -1.8° and +6.3°, the roll angle varied from -8.4° left wing down to 8.8° right wing down, and the vertical acceleration varied between -0.69G and +1.68G."
The NTSB highlighted that during the turbulence event, the A320 climbed from 33,980 ft (10,357 m) to 34,790 ft (10,603 m), with the Mach speed varying between 0.732 and 0.820. During the event, the longitudinal wind recorded on the FDR varied from 13 knots headwind to 39 kt tailwind, and the computed crosswind varied between 31 kt right crosswind and 24 kt left crosswind.
Photo: Robin Guess | Shutterstock
At 03:37:08, while flying at 34,776 ft (10,599 m), the autopilot disconnected as the captain pushed the A320's nose down. Around 32 seconds later, the JetBlue aircraft had left the area of turbulence , and the captain descended back to the assigned altitude of 34,000 ft (10,363 m).
Once again, the flight crew reiterated to the NTSB that their radars did not show anything before they encountered turbulence, with the only returns showing adverse weather north of their flight path.
In a post-incident analysis, the NTSB concluded that there were no Significant Meteorological Information (SIGMET) advisories, no flash total lightning activity in the ten minutes before and four after the event, and the Global Data Assimilation System (GDAS) model data analyzed by Rawinsonde Observation (RAOB) program, showed wind near 35,000 ft (10,668 m) from the south at around 15 kt.
"RAOB did not identify any moderate or greater clear air turbulence in the atmosphere."
The investigators also looked at the Geostationary Operational Environmental Satellite (GOES)-16 infrared (10.3µm) data, with the NTSB noting that the accident location coincided with a cloud pattern consistent with convective activity.
"An approximately 2-minute portion of the accident aircraft's flight path (south-to-north) across the cloud pattern consistent with convective activity reveals that the accident aircraft flew across the coldest portion of the cloud, which was at a brightness temperature of -55°C."
Photo: NTSB Related 5 Passengers & 6 Crew Injured During Severe Turbulence On Lufthansa Boeing 747 Flight From Buenos Aires To Frankfurt
The Lufthansa Boeing 747-8, involved in the incident later departed for a flight to San Fransisco.
Posts 7 Continuing to Fort Lauderdale
After the brief turbulence encounter, the JetBlue aircraft continued flying from Guayaquil José Joaquín de Olmedo International Airport (GYE) to Fort Lauderdale-Hollywood International Airport (FLL) and landed at the Floridan airport at 05:18:27.
The flight crew logged the weather radar unit as inoperative. However, later testing while the radar was still installed on the aircraft showed no electrical shorts. After a subsequent offsite test by the manufacturer, the radar passed all test requirements.
Photo: Vincenzo Pace | Simple Flying
In total, the incident resulted in nine people being injured, including two flight attendants and two passengers with minor injuries. Four travelers sustained serious injuries.
The NTSB concluded that the probable cause of the incident was an inadvertent encounter with convectively induced turbulence while cruising that had not shown up on the aircraft's weather radar system.
Related Korean Air Updates Cabin Service Procedures To Address Turbulence Risk
The changes will affect Korean Air's medium and long-haul flights.
Posts 2