An air carrier light transport crew lost a bolt in their landing gear causing a violent shimmy.

Attributes
ACN	230388
Time
Date	199212
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : iad
State Reference	VA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Flight Phase	landing other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : cfi pilot : commercial pilot : instrument
Experience	flight time last 90 days : 100 flight time total : 1400 flight time type : 300
ASRS Report	230388
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	none taken : detected after the fact
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

I personally conducted a thorough preflight before we flew the airplane. After a smooth, uneventful touchdown on runway 1L at dulles international airport (iad), the airplane decelerated normally. Upon slowing to approximately 40-50 KTS, the airplane shook violently. We were able to slow down while remaining on the runway centerline. We thought that we had possibly blown a tire, so a gentleman from airport operations drove out to look at our tires after we had turned onto the taxiway. He said that all of our tires appeared to be inflated. While taxiing to the gate, the airplane shook violently again -- very similar to the first time. We called our maintenance operations. The mechanic took a quick look. He said he didn't see anything obviously wrong with the airplane or landing gear. We called our maintenance department again, and they said to see if we could make it home with the airplane. We went out to the airplane and conducted another thorough preflight, and noticed a problem with the right main landing gear. A bolt on the torque knee had come out, and the right landing gear had spun around 180 degrees. Needless to say, the airplane was unable to be flown. The following day, 2 mechanics replaced the landing gear, and we flew back to our base.

Original NASA ASRS Text

Title: AN ACR LTT CREW LOST A BOLT IN THEIR LNDG GEAR CAUSING A VIOLENT SHIMMY.

Narrative: I PERSONALLY CONDUCTED A THOROUGH PREFLT BEFORE WE FLEW THE AIRPLANE. AFTER A SMOOTH, UNEVENTFUL TOUCHDOWN ON RWY 1L AT DULLES INTL ARPT (IAD), THE AIRPLANE DECELERATED NORMALLY. UPON SLOWING TO APPROX 40-50 KTS, THE AIRPLANE SHOOK VIOLENTLY. WE WERE ABLE TO SLOW DOWN WHILE REMAINING ON THE RWY CTRLINE. WE THOUGHT THAT WE HAD POSSIBLY BLOWN A TIRE, SO A GENTLEMAN FROM ARPT OPS DROVE OUT TO LOOK AT OUR TIRES AFTER WE HAD TURNED ONTO THE TXWY. HE SAID THAT ALL OF OUR TIRES APPEARED TO BE INFLATED. WHILE TAXIING TO THE GATE, THE AIRPLANE SHOOK VIOLENTLY AGAIN -- VERY SIMILAR TO THE FIRST TIME. WE CALLED OUR MAINT OPS. THE MECH TOOK A QUICK LOOK. HE SAID HE DIDN'T SEE ANYTHING OBVIOUSLY WRONG WITH THE AIRPLANE OR LNDG GEAR. WE CALLED OUR MAINT DEPT AGAIN, AND THEY SAID TO SEE IF WE COULD MAKE IT HOME WITH THE AIRPLANE. WE WENT OUT TO THE AIRPLANE AND CONDUCTED ANOTHER THOROUGH PREFLT, AND NOTICED A PROB WITH THE R MAIN LNDG GEAR. A BOLT ON THE TORQUE KNEE HAD COME OUT, AND THE R LNDG GEAR HAD SPUN AROUND 180 DEGS. NEEDLESS TO SAY, THE AIRPLANE WAS UNABLE TO BE FLOWN. THE FOLLOWING DAY, 2 MECHS REPLACED THE LNDG GEAR, AND WE FLEW BACK TO OUR BASE.

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.