LR55 has steering problems on takeoff roll, departs runway.

Attributes
ACN	323604
Time
Date	199512
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : phl
State Reference	PA
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Learjet 55
Operating Under FAR Part	Part 91
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : cfi pilot : atp
Experience	flight time last 90 days : 140 flight time total : 4050 flight time type : 150
ASRS Report	323604
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

We were cleared to taxi our lear 55 to runway 35 at phl from FBO. We proceeded via the parallel taxiway and held short of the runway. We received takeoff clearance and taxied to the end of the runway, completed the before takeoff checklist, used a brake release takeoff roll. Power was set by copilot, and 'airspeed alive' callout was made by the copilot. At that time, I disengaged steering and the aircraft veered to the left. We exited the runway approximately 300 ft from threshold and I maintained directional control after, but could not bring aircraft back onto runway. Abort takeoff procedures were completed and the aircraft came to a stop approximately 10-20 ft from the runway in a parallel position. I'm not sure whether it was a steering malfunction, or re-engagement, or blown nose tire that caused the aircraft to go left. There was no damage to aircraft except blown nose tire and bent wheel. No other aircraft were involved in the incident, but a B747 landed on a perpendicular runway before we initiated takeoff roll. Callback conversation with reporter revealed the following information: reporter states maintenance was unable to find any steering problem. They are now checking to see if the nosewheel might have gone flat prior to takeoff and the wheel castered. Reporter indicated he would call back with information when something is determined.

Original NASA ASRS Text

Title: LR55 HAS STEERING PROBS ON TKOF ROLL, DEPARTS RWY.

Narrative: WE WERE CLRED TO TAXI OUR LEAR 55 TO RWY 35 AT PHL FROM FBO. WE PROCEEDED VIA THE PARALLEL TXWY AND HELD SHORT OF THE RWY. WE RECEIVED TKOF CLRNC AND TAXIED TO THE END OF THE RWY, COMPLETED THE BEFORE TKOF CHKLIST, USED A BRAKE RELEASE TKOF ROLL. PWR WAS SET BY COPLT, AND 'AIRSPD ALIVE' CALLOUT WAS MADE BY THE COPLT. AT THAT TIME, I DISENGAGED STEERING AND THE ACFT VEERED TO THE L. WE EXITED THE RWY APPROX 300 FT FROM THRESHOLD AND I MAINTAINED DIRECTIONAL CTL AFTER, BUT COULD NOT BRING ACFT BACK ONTO RWY. ABORT TKOF PROCS WERE COMPLETED AND THE ACFT CAME TO A STOP APPROX 10-20 FT FROM THE RWY IN A PARALLEL POS. I'M NOT SURE WHETHER IT WAS A STEERING MALFUNCTION, OR RE-ENGAGEMENT, OR BLOWN NOSE TIRE THAT CAUSED THE ACFT TO GO L. THERE WAS NO DAMAGE TO ACFT EXCEPT BLOWN NOSE TIRE AND BENT WHEEL. NO OTHER ACFT WERE INVOLVED IN THE INCIDENT, BUT A B747 LANDED ON A PERPENDICULAR RWY BEFORE WE INITIATED TKOF ROLL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES MAINT WAS UNABLE TO FIND ANY STEERING PROB. THEY ARE NOW CHKING TO SEE IF THE NOSEWHEEL MIGHT HAVE GONE FLAT PRIOR TO TKOF AND THE WHEEL CASTERED. RPTR INDICATED HE WOULD CALL BACK WITH INFO WHEN SOMETHING IS DETERMINED.

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.