A C172 pilot inadvertently taxies off the taxiway at night into a ditch.

Attributes
ACN	612493
Time
Date	200403
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : prc.airport
State Reference	AZ
Altitude	agl single value : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	general aviation : personal
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Flight Phase	ground : taxi
Flight Plan	None
Aircraft 2
Controlling Facilities	tower : prc.tower
Make Model Name	Any Unknown or Unlisted Aircraft Manufacturer
Flight Phase	ground : holding
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : cfi pilot : multi engine pilot : instrument pilot : commercial
Experience	flight time last 90 days : 7 flight time total : 340 flight time type : 230
ASRS Report	612493
Events
Anomaly	excursion : taxiway
Independent Detector	other flight crewa
Resolutory Action	none taken : detected after the fact
Supplementary
Problem Areas	Environmental Factor Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance

Narrative:

After landing on runway 21R, we exited the runway onto taxiway C. Ground cleared us to taxi back to parking. Shortly after ground amended our taxi instructions, ground told us to offset at C4 to the north ramp for opposite traffic. Both me and the opposite traffic only had the navigation lights and beacons on. The opposite traffic was stopped on the other side of C4 waiting for me to turn onto C4. I was navigating the taxiway only by the taxi edge lights. I saw the sign for C4. Since I thought the sign for C4 was on the far side of the taxiway, I proceeded to turn in front of the sign. The sign for C4 was on the near side and I ended up turning early into the grass and into the ditch. Upon stopping, I shut the engine down and called ground to let them know I was in the ditch. The only visual damage to the aircraft was the propeller was scratched up on the tips. To help prevent this from happening, I recommend prc set a standardized distance for all taxiway edge lights. There was not set standard distance making judgement of where one is more difficult than it should be. A second thing to help prevent this is better situational awareness while taxiing at night.

Original NASA ASRS Text

Title: A C172 PLT INADVERTENTLY TAXIES OFF THE TXWY AT NIGHT INTO A DITCH.

Narrative: AFTER LNDG ON RWY 21R, WE EXITED THE RWY ONTO TXWY C. GND CLRED US TO TAXI BACK TO PARKING. SHORTLY AFTER GND AMENDED OUR TAXI INSTRUCTIONS, GND TOLD US TO OFFSET AT C4 TO THE N RAMP FOR OPPOSITE TFC. BOTH ME AND THE OPPOSITE TFC ONLY HAD THE NAV LIGHTS AND BEACONS ON. THE OPPOSITE TFC WAS STOPPED ON THE OTHER SIDE OF C4 WAITING FOR ME TO TURN ONTO C4. I WAS NAVING THE TXWY ONLY BY THE TAXI EDGE LIGHTS. I SAW THE SIGN FOR C4. SINCE I THOUGHT THE SIGN FOR C4 WAS ON THE FAR SIDE OF THE TXWY, I PROCEEDED TO TURN IN FRONT OF THE SIGN. THE SIGN FOR C4 WAS ON THE NEAR SIDE AND I ENDED UP TURNING EARLY INTO THE GRASS AND INTO THE DITCH. UPON STOPPING, I SHUT THE ENG DOWN AND CALLED GND TO LET THEM KNOW I WAS IN THE DITCH. THE ONLY VISUAL DAMAGE TO THE ACFT WAS THE PROP WAS SCRATCHED UP ON THE TIPS. TO HELP PREVENT THIS FROM HAPPENING, I RECOMMEND PRC SET A STANDARDIZED DISTANCE FOR ALL TXWY EDGE LIGHTS. THERE WAS NOT SET STANDARD DISTANCE MAKING JUDGEMENT OF WHERE ONE IS MORE DIFFICULT THAN IT SHOULD BE. A SECOND THING TO HELP PREVENT THIS IS BETTER SITUATIONAL AWARENESS WHILE TAXIING AT NIGHT.

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.