Douglas DC8 N803DH

Summary

On 7 January 2010, a Douglas DC8 registered N803DH, operated by Astar Air Cargo Inc, was involved in an incident near Cincinnati (CVG), Ohio, United States. 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

7 January 2010

Classification

Incident

Location

Cincinnati (CVG), Ohio, United States

Nearest airport

Cincinnati International Airpo (CVG)

Coordinates

39.0803, -84.7006

Aircraft

Douglas DC8

Registration

N803DH

Category

Airplane

Engines

4

Operator

Astar Air Cargo Inc

Operating rule

Part 121: Air Carrier

Phase of flight

Not recorded

Route

Unknown → Cincinnati

Aircraft damage

Minor

NTSB number

ENG10IA016

Nobody was injured.

Failure of the NLG cylinder occurred by intergranular rupture; coincidental to a chrome plating crack. The failure origin occurred along the inner surface of the cylinder and then propagated by stress corrosion cracking to the outer surface. A secondary crack with the same features as the primary crack was found diagonal to the primary crack. Both cracks initiated by intergranular cracking due to grinding burns caused by abusive grinding and propagated by stress corrosion cracking. Hydrogen embrittlement did not contribute to the intergranular cracking.

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

Read the full NTSB narrative

On January 7, 2010 Astar Air Cargo reported that during of a DC-8-73 hydraulic fluid leaking from a small crack at the upper end of the nose landing gear (NLG) cylinder. The following day, during taxi to the maintenance hangar, a loud bang was heard after a turn. Further inspection revealed that the NLG cylinder had fractured. The NLG was overhauled in April 2007 by AAR Landing Gear Services (LGS) in Miami Florida. The NLG was installed on the incident airplane on January 5, 2010 and had accumulated one ground air ground (GAG) cycle prior to the failure. The NLG assembly was removed and replaced and the failed cylinder was submitted to the Boeing Huntington Beach Failure Analysis Laboratory for failure analysis. At the time of the incident it was reported that the airplane had accumulated 86,911 flight hours and 32,212 cycles. The NLG cylinder failed due to intergranular (IG) cracking at the inner surface of the cylinder coincidental to a chrome plating crack, then propagated by stress corrosion cracking. The plating crack was determined to be cleavage fracture and could have occurred during the grinding of the chrome plating to size. The fracture surfaces of the primary and secondary crack, each exhibited a combination of dark gray and orange-brown discoloration that extended to 0.95 and 0.85 inches, respectively, and towards the outer surface of the cylinder. A short distance from the outer surface of the cylinder, there was no observable discoloration on the fracture surface of the primary crack. The discoloration indicated that the fracture occurred over an unknown period of time. Etch inspection of the inner surface of the cylinder revealed evidence of circumferential grinding burns. Light circumferential scratches were also observed however their origin could not be determined.

Quoted verbatim from the NTSB record.