FlarePath
Cases › DCA18FA144 · Part 121 airline

MCDONNELL DOUGLAS DC 9 83(MD-83)Caribbean Sun Airlines Inc

Alexandria, LA, USA · 2018-04-20·N807WA

0
fatal
0
serious
No injury
highest injury
Substantial
damage
Replay the flight data4,618 samples · 21 parameters14:14:45.0 – 14:17:14.0Replay the flight data2,880 samples · 19 parametersSRN 1,404,533 – SRN 1,404,629Replay the flight data4,200 samples · 19 parametersSRN 1,394,520 – SRN 1,394,660AnalyseThe analystOne timeline · precedents · ask the docket · what the record saysGenerateInvestigation briefFacts, cause, recorder extremes, sequence, sourcesSourceNTSB docket15 documents on data.ntsb.gov

What happened

NTSB summary, verbatim

The airplane suffered a right main landing gear collapse during landing at the destination airport. The airplane sustained substantial damage to the right lower wing skin when it contacted the runway after the landing gear collapse. The crew stopped the airplane on the runway and an emergency evacuation was performed through three of the four doors on the airplane. The escape slide at the left forward door did not deploy or inflate due to the depletion of the gas charge in the reservoir. The reservoir depleted due to a leak in the valve assembly and was not caught during multiple inspections since installation of the slide assembly in the airplane. The landing gear cylinder fractured under normal landing loads due to the presence of a fatigue crack on the forward side of the cylinder in an area subject to an AD inspection for cracks. The most recent AD inspection of the cylinder was performed 218 landings prior when the fatigue crack was large enough to be detectable. A previous AD inspection performed 497 landings prior to the accident also did not detect the crack that would have been marginally detectable at the time.

Photographs

1the aircraft, and what the investigators found
The aircraft before the accident
World Atlantic Airlines McDonnell Douglas MD-83 (N807WA) at Miami International Airport
Venkat Mangudi · CC BY 2.0 · Wikimedia Commons

Probable cause

the Board's determination
the failure of the right main landing gear under normal loads due to fatigue cracking in an area subject to an FAA Airworthiness Directive that was not adequately inspected.

Occurrence sequence

3 stepsNTSB coding · CICTT taxonomy
  1. 1 · Landing-landing roll
    Sys/Comp malf/fail (non-power)
    defining event
  2. 2 · Landing-landing roll
    Landing gear collapse
  3. 3 · After landing
    Evacuation

Findings

3 causal · 0 contributing
  • CAUSE
    Aircraft › Aircraft systems › Landing gear system › Main landing gear — Inadequate inspection
  • CAUSE
    Aircraft › Aircraft systems › Landing gear system › Main landing gear — Fatigue/wear/corrosion
  • CAUSE
    Aircraft › Aircraft systems › Landing gear system › Main landing gear — Failure

Sequence of events

1 timed eventsfrom the FDR factual report · claude-sonnet-5
  1. Not specified (no discrete sequence of events narrative provided)N/Ap.2
    No sequence of events narrative was included in this factual report; report contains recorder description, time correlation methodology, and parameter list only

NTSB analysis

from the final report

The airplane suffered a right main landing gear collapse during landing at the destination airport. The airplane sustained substantial damage to the right lower wing skin when it contacted the runway after the landing gear collapse. The crew stopped the airplane on the runway and an emergency evacuation was performed through three of the four doors on the airplane. The escape slide at the left forward door did not deploy or inflate due to the depletion of the gas charge in the reservoir. The reservoir depleted due to a leak in the valve assembly and was not caught during multiple inspections since installation of the slide assembly in the airplane. The landing gear cylinder fractured under normal landing loads due to the presence of a fatigue crack on the forward side of the cylinder in an area subject to an AD inspection for cracks. The most recent AD inspection of the cylinder was performed 218 landings prior when the fatigue crack was large enough to be detectable. A previous AD inspection performed 497 landings prior to the accident also did not detect the crack that would have been marginally detectable at the time.