If you google an XLs warning system you can find a pdf of it. The one I found has a "no takeoff" annunciator that does not include the parking brake. Might not be accurate but if it is and there have been previous incidents where partial application of the brake was involved I would think NTSB and/or Cessna would make it a point to insure crews checked the parking brake knob to be fully in/off before takeoff.

Thers been, at least, one XLS overrun where the crew forgot the flaps, selected the flaps and didn’t realize the stab was still moving. Couldn’t rotate, tried to stop and overran at KPWK. I don’t think any XLS had brake induced accident.

This seems like it might be one, ASN Aircraft accident Cessna 560XL Citation Excel N91GY Oroville Airport, CA (OVE) (aviation-safety.net), and I think there have been 1 or 2 internationally. I have no firm proof but after Oroville maybe somebody should have put out a warning to make sure the parking brake activator is fully deactivated. I am not familiar with the bird at all but in a casual conversation with a buddy who flies a CJ2 he was surprised to learn about the accident and possible parking brake involvement and is going to put it on his checklist now. he was of the opinion that the bird wouldn't move with the parking brake on. Does anybody out there fly an airliner that won't give a takeoff warning with the parking brake engaged?

Does anyone know of a plane that will taxi on dry pavement with brake engaged? Campbell’s Soup went off the end of icy Meigs and lost all on-board. But,yes, the parking brake will give a NO TKEOFF warning on all types I flown.

Parking Brake Was Set
 

https://www.nbcconnecticut.com/news/...ngton/2591922/

Parking Brake Was Set at Time of Fatal Farmington Jet Crash: NTSB Report

The National Transportation Safety Board has released its preliminary report on the investigation into a plane crash in Farmington that killed four people and injured four others earlier this month.

The plane, a Cessna 560, was heading from Robertson Field Airport in Plainville to Dare County Regional Airport in Manteo, North Carolina when it crashed into the Trumpf production facility on Hyde Road in Farmington on Sept. 2 just before 10 a.m.

A pilot from Bristol, a pilot from Danbury, and a couple from Boston were killed.

The two pilots who died in the crash were William O’Leary, 55, of Bristol, Connecticut, and Mark Morrow, 57, of Danbury.
The two passengers were 33-year-old Courtney Haviland, and 31-year-old William Shrauner, a husband and wife from Boston, Massachusetts.The couple both worked as doctors in Boston, Shrauner at Brigham and Women's Hospital and Haviland at MassGeneral Hospital for Children.

The report says the cockpit, cabin, and wings were nearly consumed by fire after the crash and the parking brake handle in the cockpit and the valve that it controlled were both in the brake set position.

According to the NTSB report, one witness reported that the airplane hit a powerline pole, causing a small explosion near the right engine, then there was a shower of sparks before the witness lost sight of the plane when it was behind trees.

Witnesses told investigators that the airplane was going slower than they had seen during previous takeoffs and there was a puff of blue smoke from the backside of the airplane.

The flight data recorder showed the plane's acceleration values on the runway prior to the crash were lower than its two previous takeoffs, according to the NTSB report.

One witness reported that the nose landing gear was still on the ground as the airplane passed a taxiway intersection near the mid-point of the runway and he said to a friend that something was wrong.

NTSB investigators also said marks from the main landing gear went past the end of the runway and onto a grassy area.

Investigators found no anomalies with any of the airplane’s primary or secondary flight control surfaces.

In a Facebook post, the Trumpf company said two employees were injured because of the crash. Police said the injuries were not life-threatening and all of the other employees have been accounted for.

The NTSB report says one person on the ground sustained serious injuries and three people sustained minor injuries.

Actually, the prelim says the parking handle and valve were positioned in the set position. They doesn’t specifically mean the brake was set. They had sub-standard acceleration, but reached 100 knots on the runway.

Didn't Rich manage to take off in a Q-400 with the parking brake set or something?

I’m still struggling to understand how this happened.
Was the parking brake set on the taxiway to contact ATC for a release time?

Doesn't the parking brake valve just trap pressure in the normal brake line? So it's possible the handle was set with light brake application and the aircraft can still be moved. Other forums have had posters who espoused the idea that with partial brake application on the TO roll the application becomes stronger as the brakes heat up explaining the skid marks. N91GY will probably be the same thing and one wonders if a warning should have been given by FAA/Cessna although I would think the parking brake would be on the TO checklist since it was not part of the TO warning system.

Probably something like that. I normally set the brake when stopping, and most certainly at the hold short or if going heads-down.