Accident Boeing 737-8Q8 (WL) N820TJ,
ASN logo
 

Date:Tuesday 19 May 2020
Time:15:16
Type:Silhouette image of generic B738 model; specific model in this crash may look slightly different    
Boeing 737-8Q8 (WL)
Owner/operator:Swift Air
Registration: N820TJ
MSN: 28218/160
Year of manufacture:1998
Engine model:CFMI CFM56-7B26
Fatalities:Fatalities: 0 / Occupants: 95
Aircraft damage: Substantial, repaired
Category:Accident
Location:W of Victorville-Southern California Logistics Airport, CA (VCV) -   United States of America
Phase: Initial climb
Nature:Passenger - Scheduled
Departure airport:Victorville-Southern California Logistics Airport, CA (VCV/KVCV)
Destination airport:San Diego International Airport, CA (SAN/KSAN)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
Swift Air flight 3518, a Boeing 737-800, N820TJ, was climbing through about 8,000 feet when the flight crew heard a loud bang but the systems and engine indications remained normal. The flight crew elected to continue to San Diego International Airport (SAN), California. Post-flight examination of the airplane found that the vertical stabilizer dorsal fin and several other panels were missing. The left horizontal stabilizer was substantially damaged from impact with the missing components.

On February 26, 2019 (less than 3 months before the accident), the fuselage skin under the dorsal fin was inspected at iAero Repair Station, Miami, Florida. This inspection was done every 24,000 flight cycles to identify and remove corrosion. The maintenance instructions for the dorsal fin indicated that the mechanic should note the type and location of the bolts removed to ensure that each bolt would be returned to the same location from where it was removed. (The dorsal fin had different bolts with varying grip lengths.) Once the bolts were reinstalled, sealant was applied to the bolt heads.

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.

Probable Cause: Improper installation of dorsal fin attach bolts which caused the dorsal fin to separate during flight, substantially damaging the left horizontal stabilizer.

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: DCA20LA107
Status: Investigation completed
Duration: 2 years 1 month
Download report: Final report

Sources:

NTSB

History of this aircraft

Other occurrences involving this aircraft
18 October 2008 D-AXLF XL Airways 0 Beograd unk
3 September 2012 D-AXLF XL Airways 0 Cologne-Bonn airport non

Location

Images:


photo (c) FAA; Victorville-Southern California Logistics Airport, CA (VCV); May 2020; (publicdomain)

Revision history:

Date/timeContributorUpdates

The Aviation Safety Network is an exclusive service provided by:
Quick Links:

CONNECT WITH US: FSF on social media FSF Facebook FSF Twitter FSF Youtube FSF LinkedIn FSF Instagram

©2024 Flight Safety Foundation

1920 Ballenger Av, 4th Fl.
Alexandria, Virginia 22314
www.FlightSafety.org