NTSB Identification: CHI91MA224.
The docket is stored on NTSB microfiche number 44798.
Accident occurred Monday, July 22, 1991 in DETROIT, MI
Probable Cause Approval Date: 09/11/1992
Aircraft: LEARJET 23, registration: N959SC
Injuries: 3 Fatal.

NTSB investigators traveled in support of this investigation and used data obtained from various sources to prepare this aircraft accident report.

A LINEMAN NOTED PARKING BRAKE (P/B) WAS SET BFR FLT. PLTS BGN TKOF ON 5147' RWY WITH 10 KT X-WND. A WITNESS SAID ACFT ROTATED FOR TKOF ABT 4500' DWN RWY & LIFTED OFF ABT 50' LTR. RPRTDLY, IT RMND LOW & SLOW (20-60 FT AGL) AFTER LIFT-OFF, THEN BANKED (ROCKED) LEFT & RIGHT IN NOSE HI ATTITUDE, SETTLED, HIT TREES & CRASHED ABT 200' BYD RWY. ONE PERSON SAID ACFT WENT OUT OF CTL BFR IMPACT; ANOTHER SAID IT WAS 'IN OR ON THE EDGE OF STALLED FLIGHT.' EXAM SHOWED ROTATIONAL DMG OCCURRED IN BOTH ENGS DRG IMPACT. THE BRAKING SYS HAD EVIDENCE THAT P/B CTL VLV WAS PARTIALLY ON; BRAKE TORQUE TUBE CONTAINED HEAT BLUEING. ON THIS EARLY MODEL (LEARJET 23/SN: 23-45A), P/B HAD TO BE RLSD BY DEPRESSING BRAKE PEDALS 1ST; PLT HANDBOOK DID NOT ADDRESS THIS. ON LTR MODELS (SN: 23-050 & UP), P/B NEEDED ONLY TO BE MOVED 'OFF.' INV SHOWED LEFT SEAT PLT HAD TRNG IN LATER MODELS (LEARJET 24/25); BUT ONLY A BIENNIAL FLT REVIEW WAS NOTED IN THE MODEL 23. COMPANY DISPATCHER SAID NO TRNG WOULD HAVE BEEN PERFORMED ON ACDNT FLT (WITH PSGR ABOARD). ACFT WAS ABT 430 LBS OVR MAX WT LMT.

The National Transportation Safety Board determines the probable cause(s) of this accident to be:

IMPROPER PREFLIGHT BY THE PILOT, HIS FAILURE TO ABORT THE TAKEOFF WHILE THERE WAS SUFFICIENT RUNWAY REMAINING, AND HIS FAILURE TO ASSURE THAT THE AIRCRAFT ATTAINED SUFFICIENT AIRSPEED FOR LIFT-OFF AND CLIMB. FACTORS RELATED TO THE ACCIDENT WERE: THE PILOT'S FAILURE TO ASSURE THE AIRCRAFT WAS WITHIN ITS MAXIMUM WEIGHT LIMITATION, HIS IMPROPER USE OF THE PARKING BRAKE, AND INSUFFICIENT INFORMATION IN THE PILOT OPERATING HANDBOOK CONCERNING THE AIRCRAFT PARKING BRAKE.

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