Investigation brief · generated 2026-10-09 · source: NTSB public docket and accident database
BOEING 737 — Victorville, CA, USA, 2020-05-19
NTSB number
DCA20LA107
Operator
Swift Air LLC
Registration
N820TJ
Highest injury
No injury
Regulation
Part 121
Damage
Substantial
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
After departure, the air carrier airplane was climbing through an altitude of about 8,000 ft, at which time the flight crew heard a loud bang. Because the flight instruments and gauges showed nothing abnormal, the flight crew elected to continue the flight to the destination airport. The airplane landed uneventfully. Postflight inspection of the airplane found that the dorsal fin and three panels on the lower left side of the vertical stabilizer were missing, and that the left horizontal stabilizer was substantially damaged.
Most of the dorsal fin, the vertical stabilizer panels, and 7 of the 14 bolts attaching the dorsal fin to the fuselage were not recovered. Of the seven bolts that were recovered, four remined installed, and three were found loose. Three of the four installed bolts remained attached to pieces of the dorsal fin structure. Examination of the photographs showed that the bolts installed in three positions on the left side of the dorsal fin were the correct part number. The bolt installed in a position on the right side of the dorsal fin was not the correct part number, and the bolt was longer than required. The photographs also showed remnants of old sealant at each of the bolt locations but no evidence that sealant was applied during maintenance of the dorsal fin in February 2019 (less than 3 months before the accident).
The seven missing bolts for the dorsal fin structure became loose, had fractured, or were not properly installed.
Improper installation of dorsal fin attach bolts which caused the dorsal fin to separate during flight, substantially damaging the left horizontal stabilizer.
Verbatim, NTSB determination.
Flight data recorder
Boeing 737-800 · N820TJ — 111,555 samples, 19 parameters, 15:11:50.0 to 16:02:08.9.
Parameter
Max
at
Min
at
Final
at
Pressure altitude ft
15,955.0
15:31:42.7
-158.0
15:55:44.7
-92.0
16:02:08.7
Computed airspeed kts
303.0
15:39:28.7
45.0
15:11:50.7
45.0
16:02:08.7
Vertical acceleration g
1.4
15:16:16.9
0.6
15:20:36.1
1.0
16:02:08.9
Computed from the docket's tabular attachment; times as recorded (local or SRN as published).
Sequence of events (FDR factual report)
Time
Event
Page
15:14:38 PDT
Aircraft took off from Victorville Airport (VCV), Victorville, California
2
15:55:38 PDT
Aircraft landed at San Diego International Airport (SAN), San Diego, California
2
Extracted by claude-sonnet-5; 2 of 2 stated events verified against the raw recorder data.