Los Angeles, CA, USA
N394AE
SAAB-SCANIA SAAB 340B
The airplane encountered turbulence at 5,000 feet mean sea level (msl) during an approach to landing and the sole flight attendant was knocked unconscious and sustained serious injuries. The airplane was about 7 minutes from landing, and the flight attendant was completing his before landing checklist when turbulence was encountered. After regaining consciousness a few seconds later, he was able to get to an empty passenger seat. A deadheading flight attendant assumed the incapacitated flight attendant's duties. Review and analysis of available weather data and forecast products showed that airman's meteorological information (AIRMET) Update 6 was issued by the National Weather Service (NWS) and in effect for the flight for occasional moderate turbulence below 12,000 feet. A review of the meteorological data showed that the airplane was operating in conditions that would have supported at least moderate turbulence below 10,000 feet msl. The weather packet included in the flight release provided to the flight crew by the airline's dispatch prior to the flight contained information for AIRMET Update 3; however, AIRMET Update 6 (valid for the accident flight) was not listed. Information contained on the release indicated to the crew that no moderate or greater turbulence was present along the route of flight. At the time of the accident, the airline's contract weather provider evaluated current meteorological data and staff meteorologists used their judgment of the weather to issue a SIGMEC (significant meteorological conditions, a company issued advisory) based on the current weather conditions. NWS-issued SIGMET Yankee was canceled at 1630 because the current pilot reports (PIREPS) indicated that previously forecasted turbulent conditions had diminished. Although an AIRMET was in effect at the time of the accident for moderate or greater turbulence, there were no other supporting indicators to the airline staff meteorologist that moderate or greater turbulence was present along the route of flight. Due to the cancellation of the SIGMET and the lack of additional supporting information for moderate or greater turbulence, the meteorologist did not issue a SIGMEC. Therefore, the turbulence information was not on the flight release provided to the flight crew.
HISTORY OF FLIGHT On February 11, 2005, at 1645 Pacific standard time, a Saab 340B, N394AE, encountered turbulence during an approach to landing at Los Angeles International Airport, Los Angeles, California. During the turbulence encounter, the flight attendant was knocked unconscious. American Eagle (AE) was operating the airplane as flight 3030 under the provisions of 14 CFR Part 121 as a domestic scheduled passenger flight. The airline transport pilot, commercial copilot, and 28 passengers were not injured; the sole flight attendant sustained serious injuries. The flight departed from Monterey, California, at 1528, and was destined for Los Angeles. Visual meteorological conditions prevailed, and the flight was operating on an instrument flight plan. According to the airline's safety officer, the airplane passed over the Ventura (VTU) vhf omni-directional range (VOR) (VTU) at 5,000 feet mean sea level, and about 4 minutes later, the flight crew encountered turbulence. The airplane was about 7 minutes from landing. The flight attendant was completing his before landing checklist when turbulence was encountered. The flight attendant impacted the ceiling of the cabin, lost consciousness, regained consciousness a few seconds later, and positioned himself in an empty passenger seat. A deadheading flight attendant assumed the injured flight attendant's duties. About 2 minutes prior to landing, the injured flight attendant resumed his responsibilities for the remainder of the flight. In the captain's statement supplied by AE, he reported that the flight encountered wake turbulence from a preceding Boeing 747. He stated that additional turbulence was not noted during the flight, nor was any forecast. RADAR INFORMATION A National Transportation Safety Board air traffic control specialist reviewed recorded radar data for the accident flight. The data indicated that a Boeing 747 preceded AE flight 3030 during its approach into Los Angeles. Federal Aviation Administration (FAA) regulations state that these airplanes must maintain separation of at least 6 miles when landing on the same runway. Review of the radar data showed that the spacing was at least 6 miles during the approach into Los Angeles International Airport. METEOROLOGICAL INFORMATION A Safety Board meteorologist reviewed the weather data surrounding the flight. Weather reports indicated that airman's meteorological information (AIRMET) Update 6 was issued for turbulence. The AIRMET indicated occasional moderate turbulence below 12,000 feet. The flight release for AE flight 3030 was obtained and reviewed. Investigators noted that AIRMET Update 3 was listed on the release; however, AIRMET Update 6 (valid for the accident flight) was not listed. The full meteorological factual report is located in the official docket for this accident. At the time of the accident, AE's weather provider was WNI. Information contained on the release issued by WNI indicated to the crew that no significant turbulence via significant meteorological information (SIGMETs) or significant meteorological conditions (SIGMECs) was present. According to AE personnel, WNI procedures called for staff meteorologists to evaluate the weather and determine the current and forecast conditions. In the case of the accident flight, SIGMET Yankee was canceled at 1630 because the current pilot reports (PIREPS) indicated that conditions had diminished. Although an AIRMET was in effect at the time of the accident for moderate or greater turbulence, there were no other supporting indicators to the staff meteorologist that moderate or greater turbulence was present along the route of flight. The meteorologist then made a judgment call based upon the information available. In this particular case, due to the cancellation of the SIGMET and the lack of additional supporting information for moderate or greater turbulence, the meteorologist did not issue a SIGMEC. Therefore, the turbulence information was not on the release. ADDITIONAL INFORMATION The National Weather Service (NWS) issues SIGMET and AIRMET information. A SIGMEC is an internal product, specific to American Airlines (and AE), for the issuance of significant meteorological conditions based on information obtained from the NWS. AE's weather provider was changed to WSI a few weeks following the accident. WSI policy states that moderate or greater turbulence is considered SIGMEC criteria. This information is displayed through the issuance of a SIGMEC on the flight release as well as graphically on a chart. In Aviation Weather Services (AC 00-45E) it states that the maximum forecast period for an AIRMET is 6 hours. AIRMETs,"...are considered "widespread" because they must be either affecting or be forecasted to affect an area of at least 3,000 square miles at any one time. However, if the total area to be affected during the forecast period is very large, it could be that in actuality only a small portion of this total area would be affected at any one time." Federal Aviation Regulations (FAR) 121.101, Weather reporting facilities, and 121.601, Aircraft dispatcher information to pilot in command: Domestic and flag operations, outline air carrier weather procedures. FAR 121.101 states, in part, "that each certificate holder that uses forecasts to control flight movements shall use forecasts prepared from weather reports specified by the United States National Weather Service, or a source approved by the United States National Weather Service, or by a source approved by the Administrator. Furthermore, each certificate holder shall adopt and use an approved system for obtaining forecasts and reports of adverse weather phenomena." FAR 121.601 states, in part, "that before beginning a flight, the aircraft dispatcher shall provide the pilot in command with all available weather reports and forecasts of weather phenomena that may affect the safety of flight, including adverse weather phenomena."
the in-flight encounter with turbulence.
Source: NTSB Aviation Accident Database
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