A DC10 flight crew discovers after the fact that they taxied off the paved taxiway into the mud.

Attributes
ACN	524390
Time
Date	200109
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : dtw.airport
State Reference	MI
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	DC-10 10
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : flight engineer pilot : atp
Experience	flight time last 90 days : 50 flight time total : 9000 flight time type : 2500
ASRS Report	524390
Events
Anomaly	excursion : taxiway
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

While taxiing to parking after landing at detroit wayne county metropolitan airport, right main gear of our aircraft got off the concrete taxiway while making a right turn. We were entering company property from taxiway Z at the 'ingress' point to company ramp, and had to make a right turn then a left turn into our parking spot. There was a B727 parked next to our spot that we had to pass on our left during this right turn and the right turn itself looked as if it would be approximately 45 degrees before we would turn back left into our parking spot. Both these factors caused the captain to use sufficient over-steer and resulted in our getting 'into the mud.' we did not know we had gone off the concrete until we were parked and the mechanic told us there was mud on the right main gear tires. We made a write-up in the aircraft maintenance log. I knew (the main gear was) close to the taxiway edge during the right turn but did not think we would go off, or I would have told the captain to go further straight ahead (toward the B727) before turning right. In the future I will provide better guidance to the captain regarding initiating turns and not be so complacent. Company safety report filed regarding circumstances of incident with suggestion to use tow in for DC10 and larger aircraft on this small/tight ramp.

Original NASA ASRS Text

Title: A DC10 FLT CREW DISCOVERS AFTER THE FACT THAT THEY TAXIED OFF THE PAVED TXWY INTO THE MUD.

Narrative: WHILE TAXIING TO PARKING AFTER LNDG AT DETROIT WAYNE COUNTY METRO ARPT, R MAIN GEAR OF OUR ACFT GOT OFF THE CONCRETE TXWY WHILE MAKING A R TURN. WE WERE ENTERING COMPANY PROPERTY FROM TXWY Z AT THE 'INGRESS' POINT TO COMPANY RAMP, AND HAD TO MAKE A R TURN THEN A L TURN INTO OUR PARKING SPOT. THERE WAS A B727 PARKED NEXT TO OUR SPOT THAT WE HAD TO PASS ON OUR L DURING THIS R TURN AND THE R TURN ITSELF LOOKED AS IF IT WOULD BE APPROX 45 DEGS BEFORE WE WOULD TURN BACK L INTO OUR PARKING SPOT. BOTH THESE FACTORS CAUSED THE CAPT TO USE SUFFICIENT OVER-STEER AND RESULTED IN OUR GETTING 'INTO THE MUD.' WE DID NOT KNOW WE HAD GONE OFF THE CONCRETE UNTIL WE WERE PARKED AND THE MECH TOLD US THERE WAS MUD ON THE R MAIN GEAR TIRES. WE MADE A WRITE-UP IN THE ACFT MAINT LOG. I KNEW (THE MAIN GEAR WAS) CLOSE TO THE TXWY EDGE DURING THE R TURN BUT DID NOT THINK WE WOULD GO OFF, OR I WOULD HAVE TOLD THE CAPT TO GO FURTHER STRAIGHT AHEAD (TOWARD THE B727) BEFORE TURNING R. IN THE FUTURE I WILL PROVIDE BETTER GUIDANCE TO THE CAPT REGARDING INITIATING TURNS AND NOT BE SO COMPLACENT. COMPANY SAFETY RPT FILED REGARDING CIRCUMSTANCES OF INCIDENT WITH SUGGESTION TO USE TOW IN FOR DC10 AND LARGER ACFT ON THIS SMALL/TIGHT RAMP.

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.