- Date
- February 19, 2010, 23:58 UTC
- Place
- Anchorage, AK
- Injuries
- 1 serious, 25 minor, 236 uninjured
- Damage
- Minor damage
- Phase of flight
- Enroute
- Aircraft
- N173UABoeing 747
- Defining event
- Enroute-change of cruise level: Clear air turbulence encounter
- Weather
- Day
- Status
- Completed · report February 23, 2017
- Report
- Approved by Office Director
- NTSB office
- Major Investigations Division
- FAA report
- 20100219028409A
- Case key
- 75393
From the NTSB’s public API. By law, NTSB reports can’t be used as evidence in lawsuits over the accident.
On this page
Probable cause
an inadvertent encounter with clear air turbulence.
Findings · 1
NTSB’s coded findings. Those marked are part of the probable cause; the rest are factors or other findings. Under each, the cases with the same finding.
Sequence of events
The events NTSB coded, in order, by phase of flight. The defining event is the one that best describes the accident. Under each, the cases with the same event anywhere in their sequence.
Analysis
On February 19, 2010, about 1452 Alaska standard time (AKST) (2352 UTC), United Airlines flight 897, a Boeing 747-400, N173UA, encountered severe turbulence during cruise descent between FL310 and FL300 about 100 miles west of Anchorage, Alaska. Of the 243 passengers and 19 crew members on board, 17 passengers and eight flight attendants (FA) received minor injuries and one FA received a serious injury. The airplane received minor damaged. The flight was operating under 14 Code of Federal Regulations (CFR) part 121 as a regularly scheduled international passenger flight from Dulles International Airport (IAD), Washington, DC, to Narita International Airport (NRT), Narita, Japan. Prior to the turbulence encounter, the flight crew received pilot reports (PIREPs) of moderate to severe turbulence above FL340 and that it was less at FL300. According to the flight crew, about one hour late, the flight began to encounter a few "light bumps" or intermittent light "chop." The sky conditions were clear with good visibility. The captain turned on the "fasten seat belt" sign and made a public address (PA) announcement to fasten seat belts. The flight crew requested a descent to FL300 and began to encounter moderate turbulence after starting the descent. The first officer then made a PA announcement directing the flight attendants to "take your seats." The autopilot remained engaged throughout the turbulence encounter, which lasted less than one minute. After encountering the turbulence, the crew assessed airplane damage and checked the number and severity of injuries to passengers and crew. The crew was assisted in assessing passenger and crew injuries by a U.S. Army Special Forces medic who stated that all of the injuries were considered minor. All the FAs indicated that they were able to perform their required emergency duties for the remainder of the flight. After discussing the injuries and the available diversion airports with the FAs, company dispatch and the medic, the flight crew decided to continue on to NRT since there were sufficient diversion airports along the route if the situation worsened. Upon arrival in NRT, 16 passengers and one FA were transported to hospitals for medical evaluation. All were released with only minor injuries, however, the FA was re-evaluated by her personal physician when she returned home with the further diagnosis of a fractured rib.
Factual narrative
On February 19, 2010, about 1452 Alaska standard time (AKST) (2352 UTC), United Airlines flight 897, a Boeing 747-400, N173UA, encountered severe turbulence during cruise descent between FL310 and FL300 about 100 miles west of Anchorage, Alaska. Of the 243 passengers and 19 crew members on board, 17 passengers and eight flight attendants (FA) received minor injuries and one FA received a serious injury. The airplane received minor damaged. The flight was operating under 14 Code of Federal Regulations (CFR) part 121 as a regularly scheduled international passenger flight from Dulles International Airport (IAD), Washington, DC, to Narita International Airport (NRT), Narita, Japan. Prior to the turbulence encounter, the flight crew received pilot reports (PIREPs) of moderate to severe turbulence above FL340 and that it was less at FL300. According to the flight crew, about one hour late, the flight began to encounter a few "light bumps" or intermittent light "chop." The sky conditions were clear with good visibility. The captain turned on the "fasten seat belt" sign and made a public address (PA) announcement to fasten seat belts. The flight crew requested a descent to FL300 and began to encounter moderate turbulence after starting the descent. The first officer then made a PA announcement directing the flight attendants to "take your seats." The autopilot remained engaged throughout the turbulence encounter, which lasted less than one minute. After encountering the turbulence, the crew assessed airplane damage and checked the number and severity of injuries to passengers and crew. The crew was assisted in assessing passenger and crew injuries by a U.S. Army Special Forces medic who stated that all of the injuries were considered minor. All the FAs indicated that they were able to perform their required emergency duties for the remainder of the flight. After discussing the injuries and the available diversion airports with the FAs, company dispatch and the medic, the flight crew decided to continue on to NRT since there were sufficient diversion airports along the route if the situation worsened. Upon arrival in NRT, 16 passengers and one FA were transported to hospitals for medical evaluation. All were released with only minor injuries, however, the FA was re-evaluated by her personal physician when she returned home with the further diagnosis of a fractured rib.
Aircraft
- Registration
- N173UA
- Reported as
- Boeing 747 (422)
- Category
- Airplane
- Serial number
- 24380
- Engines
- Pratt and Whitney PW4000, turbo fanPratt and Whitney PW4000, turbo fanPratt and Whitney PW4000, turbo fanPratt and Whitney PW4000, turbo fan
- Damage
- Minor damage
- Flight
- Part 121
- Operator
- United Air Lines Inc
- Registered owner
- Wells Fargo Bank Northwest, N.A.
- Airworthiness certificate
- Standard, Transport
- Last inspection
- Continuous airworthiness · January 23, 2010
- Departed
- IAD · Dulles, VA
- Destination
- NRT · Narita
- Flight plan
- IFR
Matched to the registry by N-number and the event date; the registry’s history has gaps, so older matches can be wrong. Compare the reported make and model.
Flight crew · 2
As NTSB recorded them. NTSB leaves out names.
- Role
- Pilot
- Age
- 59
- Injuries
- None
- Certificates
- Airline transport, Flight instructor, Commercial
- Airplane ratings
- Multi-engine land, Single-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, Without waivers/limitations
- Seat
- Left
- Restraint
- Lap only
- Flight hours
- 15,000 total · 1,732 in this make and model · 100 in the last 90 days · 14 in the last 30 days
- Role
- Co-pilot
- Age
- 52
- Injuries
- None
- Certificates
- Airline transport, Commercial, Flight engineer, Flight instructor
- Airplane ratings
- Single-engine land, Multi-engine land
- Instrument ratings
- Airplane
- Medical
- Class 1, With waivers/limitations
- Last flight review
- December 18, 2009
- Seat
- Right
- Restraint
- Lap only
- Flight hours
- 16,500 total · 4,925 in this make and model · 32 in the last 30 days
Weather
- Conditions
- Day
- Turbulence
- Severe
Docket · 5
The files NTSB released with the investigation on February 23, 2017, on NTSB’s docket system: statements, records, photos and specialists’ reports. 2.3 MB in all.
FAA reports on this event · 1
The FAA’s own accident and incident reports, matched to the aircraft by N-number and date.
Other investigations on N173UA · 1
Matched to the same aircraft by N-number and date.