Boeing 737-8K2 N817SY

Summary

On 4 February 2022 at about 09:19 local time, a Boeing 737-8K2 registered N817SY, operated by Sun Country Airlines, Inc., was involved in an incident near Las Vegas, Nevada, United States. 56 people were on board and nobody was injured. The aircraft was slightly damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

4 February 2022 at 09:19

Classification

Incident

Location

Las Vegas, Nevada, United States

Nearest airport

Harry Reid International Airpo (LAS)

Coordinates

36.0764, -115.1420

Aircraft

Boeing 737-8K2

Registration

N817SY

Category

Airplane

Year built

2001

Engines

2

Operator

Sun Country Airlines, Inc.

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Las Vegas → Minneapolis

Aircraft damage

Minor

Weather

VMC

Light

Night

NTSB number

ENG22FA009

Nobody was injured.

The fatigue failure of the right main landing gear initiated by liquid metal embrittlement by cadmium at arc burn locations in the outer cylinder tooling hole area. The arc burns were likely the result of operator error during stylus cadmium plating operations during overhaul.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

Upon retracting the landing gear after takeoff, the flight crew received a right main landing gear (RMLG) red position indicator light, indicating that the RMLG was not in the up and locked position. The crew elected to return to the departure airport and the RMLG red indicator light remained illuminated until the crew selected the gear DOWN position for landing. During the landing roll, the RMLG collapsed, resulting in minor damage when the right engine impacted the runway. It is likely that the RMLG was partially fractured after takeoff which prevented it from retracting to the up and locked position. Examination of the RMLG revealed that the outer cylinder fractured through a tooling hole. Examination of the fracture revealed the presence of fatigue cracking that initiated at the intersection of the tooling hole inner diameter and the outer cylinder inner diameter. Four areas of arc burn damage were identified in the tooling hole area, two of which were at the crack initiation sites. Cadmium identified at the intergranular separation initiation sites indicated the crack initiated due to liquid metal embrittlement by cadmium at the arc burn locations before propagating in fatigue. The RMLG was last overhauled about 10 years before the incident, during which the outer cylinder was replated with cadmium after repair. It is likely that the arc burning in the tooling hole area was caused by a hand-held stylus cadmium plating operation performed in the tooling hole when the stylus (anode) made contact with the outer cylinder (cathode), initiating an arc. A nonconductive sleeve normally installed on the anode was either not present or deteriorated, allowing physical contact between the anode and cathode.

Quoted verbatim from the NTSB record.