A piper PA31T on ground check found severe damage on 2 left propeller blades cause unknown.

Attributes
ACN	530727
Time
Date	200111
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : zzz.airport
State Reference	US
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	general aviation : corporate
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 110 flight time total : 16000 flight time type : 265
ASRS Report	530727
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical ground encounters other
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	other other
Supplementary
Problem Areas	Airport Aircraft

Narrative:

After uneventful flight and landing I parked aircraft. While checking oil on left engine I noticed 2 of 3 blades with large gashes near but not affecting tips. Damage was severe and 2 blades required replacement. I called ZZZ tower and spoke to controller, mr X, who I explained the damage to propellers and that it must have been an object on runway. The airport inspected the runway and txwys and found no damaged light or objects. Impact marks on propellers indicates show reverse thrust at time of damage.

Original NASA ASRS Text

Title: A PIPER PA31T ON GND CHK FOUND SEVERE DAMAGE ON 2 L PROP BLADES CAUSE UNKNOWN.

Narrative: AFTER UNEVENTFUL FLT AND LNDG I PARKED ACFT. WHILE CHKING OIL ON L ENG I NOTICED 2 OF 3 BLADES WITH LARGE GASHES NEAR BUT NOT AFFECTING TIPS. DAMAGE WAS SEVERE AND 2 BLADES REQUIRED REPLACEMENT. I CALLED ZZZ TWR AND SPOKE TO CTLR, MR X, WHO I EXPLAINED THE DAMAGE TO PROPS AND THAT IT MUST HAVE BEEN AN OBJECT ON RWY. THE ARPT INSPECTED THE RWY AND TXWYS AND FOUND NO DAMAGED LIGHT OR OBJECTS. IMPACT MARKS ON PROPS INDICATES SHOW REVERSE THRUST AT TIME OF DAMAGE.

Data retrieved from NASA's ASRS site as of July 2007 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.