Investigation brief · generated 2026-10-09 · source: NTSB public docket and accident database
BOEING 757-232 — Naches, WA, USA, 2011-02-28
NTSB number
WPR11LA149
Operator
Delta Air Lines
Registration
N684DA
Highest injury
Serious injury
Regulation
Part 121
Damage
—
Cohort
Part 121 airline
Recorder data
Tier 1 — decoded recorder tables
Every sentence below is taken directly from NTSB records — the accident database, the docket's recorder reports and the Board's findings — with its source noted. Nothing is paraphrased or inferred.
NTSB summary
The flight crew of the scheduled domestic air carrier passenger flight was advised by the air route traffic control center that, due to a pilot report associated with the area of their routing, they should expect light-to-moderate chop during their descent between 20,000 feet and 16,000 feet. The flight crew, therefore, advised the passengers and the flight attendants that the descent would be bumpy and then advised the flight attendants that all descent and before-landing cabin securing activities should be completed about 10 minutes earlier than normal. Before the descent, the flight crew turned on the seatbelt sign and upon reaching 25,000 feet, the flying pilot began reducing the airspeed to that prescribed for turbulence penetration. As the airplane passed through 24,000 feet (4,000 feet higher than the altitude of the turbulence noted in the pilot report), three flight attendants were just finishing their activities, and the airplane suddenly encountered moderate turbulence for about 30 seconds. Due to the sudden movement of the airplane, the one remaining standing passenger and two of the flight attendants were thrown to the floor, one of whom sustained multiple bone fractures in her right foot.
The airplane's encounter with moderate turbulence at a higher altitude than the flight crew expected, resulting in an injury to a cabin crewmember.
Verbatim, NTSB determination.
Flight data recorder
— 6,601 samples, 11 parameters, 00:15:00.0 to 02:05:00.0.
Parameter
Max
at
Min
at
Final
at
Pressure altitude ft
36,020.0
01:32:22.0
-55,389.0
01:43:03.0
774.0
02:04:59.0
Computed airspeed kts
327.0
01:41:21.0
0.0
00:15:00.0
192.0
02:04:59.0
Pitch attitude deg
17.2
00:17:00.0
-3.5
01:40:36.0
0.0
02:04:59.0
Roll attitude deg
27.8
00:17:19.0
-30.6
01:56:34.0
0.3
02:04:59.0
Vertical acceleration g
1.8
01:42:30.0
0.7
01:43:19.0
1.0
02:04:59.0
Magnetic heading deg
336.1
01:51:37.0
11.2
02:03:35.0
89.7
02:04:59.0
Computed from the docket's tabular attachment; times as recorded (local or SRN as published).
Sequence of events (FDR factual report)
Time
Event
Page
2154 MST
Flight departed Salt Lake City, Utah
1
2240 PST (approximate)
Airplane encountered turbulence while in descent about 80 miles southeast of Seattle-Tacoma International Airport
1
SRN 6148 / 22:20:29 PST
As the aircraft was passing through approximately 22,500 feet, there were perturbations noted in the acceleration parameters
3
22:20:29 PST (initial part of upset)
The vertical acceleration experienced a change of about 1.7 g's in just over a second and the lateral acceleration had a change of about .3 g's from side to side
3
approximately one minute duration
The period of disturbance lasted about one minute
3
~20 minutes after upset
The aircraft continued to descend and landed normally
3
Extracted by claude-sonnet-5; 4 of 6 stated events verified against the raw recorder data.