Flight Crew Last 90 Days 80; Flight Crew Total 5500; Flight Crew Type 500
Situational Awareness; Time Pressure; Workload; Training / Qualification
Aircraft Equipment Problem Critical; Ground Event / Encounter Loss Of Aircraft Control
Aircraft Aircraft Damaged; Flight Crew Regained Aircraft Control
Aircraft
The last leg of the day (3rd) was an IFR (in VMC) departure from ZZZ1 to nearby ZZZ. A reposition flight with no passengers. The straight line distance between the two airports is about 7.6 miles. The initial climb instructions off the departing runway; Runway 16R; were runway heading to 5;000 ft (MSL). After I called 'Positive Rate' the Captain called for 'Gear Up'. I raised the gear and proceeded to clean the plane up (Landing Lights--Off; Spoilers--Disarm; APR--Off). I announced when we had climbed through 400 feet and the Captain asked for the After Takeoff Checklist. I asked him if he wanted Flaps Up. He declined and said no. I figured that he was wanting to keep the flaps down (Flaps 8) since we were only going a short distance so I didn't question. I completed the After Takeoff checklist minus the 'Flaps Up'.We leveled at 5;000 ft and Departure sent us south a couple of miles before vectoring us east; then north towards ZZZ. When were abeam ZZZ1; we were just east of International by a mile or two and about 5 miles southwest of ZZZ when we called it in sight and cancelled IFR. We entered final for Runway 7 about 4 miles out with the Before Landing Checklist complete. On short final we reaffirmed that Flaps were down; Gear Down--Three Green and Nose Steer on. The approach was a controlled approach; on speed and on the visual glide path and terminated with a firm controlled touchdown at the beginning of the 1;000 ft markers.As the Captain lowered the nose wheel to the ground; I looked towards the Reverser Annunciators on the EICAS to observe that both reversers were deployed and ready for power. At about that time the Captain announced that he had no brakes. I wondered to myself if the auto spoilers deployed; but quickly reached over and manually deployed the spoilers without observing the actual position of the spoilers first. As we traveled further down the runway the Captain decided to use the Emergency Brake. I believe he pulled a little too hard because I could hear that the tires were skidding on the pavement. I said 'Don't skid! Don't skid!' and we began to veer left when we noticed the Nose Wheel Steer was off. I Re-engaged the Nose Steer and it immediately turned off again. We veered to the extreme left (north) side of the runway before we started to skid back to the right (south) side of the runway. As we did so; the plane started to rotate on a horizontal plane; clockwise 180 degrees and we came to a rest at the south edge of the pavement; pointing the direction from which we came. Tires blown out; but otherwise no further evidence of damage.I was unsure what had been the true cause at first. The Captain thought it to be a brake or hydraulic failure. I wasn't sure what to think. I could have sworn I saw the white CAS message advising the spoilers were armed (Normal for when the Lear 45 is configured for take off and landing) when we had accomplished the Before Landing Checklist. The Captain reassured me they were armed after the incident and felt that it was a brake or hydraulic problem.Maintenance inspected the plane and all items of concern and could not find any system faults or defective components other than 4 blown tires. The aircraft was back in service two days later. Meanwhile I kept trying to remember what could have gone wrong. The plane exhibited all the signs you would expect when the spoilers are not armed; but I know I saw a white CAS message indicating they were armed and the Captain was certain they were armed.I thought back to earlier in the day and remembered an unrelated CAS message had occurred. It was a white 'R Fuel QTY Fault' that had occurred on climb out from Sarasota; FL. I HAD in fact seen a white CAS message when accomplishing the Before Landing Checklist. The problem is that I didn't slow down to check what the White CAS message ACTUALLY said. Had I; I am certain that I would had read the 'R Fuel QTY Fault' and not 'AUTOSPLR ARMED' CAS message I was expecting tobe there. Shortly after I told my bosses what I thought happened; Maintenance confirmed that there was in fact a 'R Fuel QTY Fault' in the system.I have concluded that the compounding factors to the incident were: 1) On departure from ZZZ1; when the spoilers were disarmed after takeoff; the flaps should have been brought up. Or; if leaving the flaps at 8; leave the spoilers armed. The preferred technique would have been to disarm spoilers and raise flaps as that is what is done after every other takeoff and departure. Either way; the two ALWAYS go together for normal takeoffs and landings. We managed the aircraft configuration in a non-standard manner; which exposed us to risk and was compounded by further mistakes.2) Although we were vectored around by Departure; it was a short distance to the destination. Keeping up with  Departure Radio communications while copying ZZZ ASOS; then monitoring CTAF at ZZZ and giving position reports as per SOP; while gathering landing performance DATA while running checklists during such a short time-frame had caused myself to become rushed and overloaded resulting in reduced effectiveness of tasks. And the viability of the checklist suffered from this.3) I am unsure to this point whether I properly challenged the Captain on the Spoilers as per Challenge/Response checklist procedures. Evidence suggests not. Because of being rushed and overloaded; I believe the Captain to not have been properly challenged by me. Did he even really hear me? I know I saw the white CAS message.4) Read the CAS messages. I just looked at the white CAS message and assumed it said one thing and in fact it said another. I should have also verified the actual position of the spoiler handle. Was it in 'Stowed' or 'Armed' position.This is a terrible case of letting myself get rushed; with a high workload; compounded by nonstandard aircraft configurations and not speaking up to the Captain. I should have asked the Captain to slow down; make a few extra turns or turn away from the field before make our final approach for landing.This will be corrected by not allowing non-standard configurations. At takeoff; spoilers are disarmed AND flaps go up. If I'm overworked; ask the Captain to slow down; make some S-Turns; hold or some type of delay until I'm caught up. Make sure that I get a response to my challenges on checklist items. Make sure that CAS messages are READ; not just seen and verify the actual position of the spoiler handle; just as is done with the gear and flaps. A more thorough pre departure briefing could likely been helpful as well.Although this is not the main factor--it did contribute--I also think to have the CAS as the only place to observe whether the auto spoilers are armed; is a bad place to put that annunciation. There is a position indicator; but it does not show and 'ARMED' status. There are so many other white CAS messages that can be on there. In this case I mistook a 'R Fuel QTY Fault' for a 'AUTOSPLR ARMED' CAS message.
LR45 crew experience a failure of the brakes upon touchdown and have to resort to pulling emergency brake handle as the aircraft begins to skid towards one side of the runway.  Aircraft continues to skid next towards the opposite side of runway where the aircraft skids 180 degrees and eventually comes to a stop.  Crew notices they had blown four tires during the ordeal.