Date: 201210
Local time of day: 0001-0600
Location: SNA.Airport, CA
Flight conditions: VMC
Weather elements / visibility: 10
Light: Night
Aircraft: Learjet 35
Operator: Air Taxi
Operating under: Part 135
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower SNA
Reporter organization: Corporate
Reporter function: Captain
Reporter qualification: Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Fatigue; Communication Breakdown; Distraction
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Incursion Runway
Detector: Person Flight Crew
When detected: In-flight
Contributing factors: Human Factors; Airport
Primary problem: Human Factors

Narrative: In night VMC conditions we lined up on and inadvertently took off from the wrong runway. Santa Ana has parallel runways; 19L and 19R. We mistook 19L for 19R. 19L is shorter (2;887 FT) and closed when the Tower is not operating. 19R is the longer of the two (5;701 FT) and the preferred runway.Upon reaching the end of the taxiway we turned onto 19L; I remember seeing and verifying the runway numbers but it did not register to us that I had said 19L when we; indeed; needed to be using 19R. I lined the plane up; stepped on the brakes; stood the power up and released the brakes. We used nearly every bit of the runway for takeoff. We did not; however; use any portion of the 400 FT overrun. It wasn't until we cleaned the plane up after our initial climb that we discussed the seemingly short takeoff run; discovered our error and realized the seriousness of the situation and the potential catastrophe we averted. It was a shock to both myself and my First Officer that we both had failed to properly identify our intended runway of use.The problem was exacerbated by the lighting conditions; our lack of sleep; our failure to use the airport diagram to our advantage; our failure to recognize the runway markings and failure to back one another up as a fail safe. I had been awake for about 19 hours prior to the occurrence. I suspect the First Officer had been up at least as long. Although the outcome was successful it was a scary lesson to learn. Always; always use the airport diagram before and while taxiing; always verify that the runway being used is in fact the runway of intended use; always take enough time to ensure a thorough thought process has been used to determine the correct course of action. I narrowly averted a potential disaster and the lessons learned are permanently seared into my memory.


Second narrative: ...we attempted to call SCT Departure on 128.1 to get our IFR release to depart. After several failed attempts on both aircraft radios to contact Departure Control the decision was made to re-attempt in the air. We switched over to CTAF and lined up and departed Runway 19L...


Synopsis: After an already long day and facing one last leg departing early in the morning hours the flight crew of a Lear 35 took off from the very short Runway 19L at SNA vice the twice as long 19R as intended.