BE99 captain experienced the collapse of the right main landing gear upon landing; cause unknown.

Attributes
ACN	1289813
Time
Date	201508
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Airliner 99
Operating Under FAR Part	Part 91
Flight Phase	Landing
Route In Use	Direct Visual Approach
Flight Plan	VFR
Component
Aircraft Component	Main Gear
Person 1
Function	Pilot Flying Single Pilot Captain
Qualification	Flight Crew Commercial Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 500 Flight Crew Total 5400 Flight Crew Type 450
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

Departure was normal; with a quick 13 min flight to ZZZZ. After a descent to pattern altitude; landing configuration was established. Final checks were done on about a two mile final. Gear indicators were established on final and all that remained to be done was a smooth touchdown considering the winds were nice and smooth from the east. After touchdown; we rolled about 20 feet and I noticed the right wing start to drop slowly towards the ground. The aircraft then proceeded to veer to the right after the airframe made contact with the surface. The aircraft was shut down by the time it came to a stop. At this time it has not yet been established as to why the gear failed.

Original NASA ASRS Text

Title: BE99 Captain experienced the collapse of the right main landing gear upon landing; cause unknown.

Narrative: Departure was normal; with a quick 13 min flight to ZZZZ. After a descent to pattern altitude; landing configuration was established. Final checks were done on about a two mile final. Gear indicators were established on final and all that remained to be done was a smooth touchdown considering the winds were nice and smooth from the east. After touchdown; we rolled about 20 feet and I noticed the right wing start to drop slowly towards the ground. The aircraft then proceeded to veer to the right after the airframe made contact with the surface. The aircraft was shut down by the time it came to a stop. At this time it has not yet been established as to why the gear failed.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.