C560 flight crew reported that a dropped ipad broke a circuit breaker collar and tripped the breaker...

Attributes
ACN	1698797
Time
Date	201910
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Citation V/Ultra/Encore (C560)
Operating Under FAR Part	Part 91
Flight Phase	Taxi
Route In Use	None
Flight Plan	IFR
Component
Aircraft Component	Circuit Breaker / Fuse / Thermocouple
Person 1
Function	First Officer Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 100 Flight Crew Total 14000 Flight Crew Type 11500
Person 2
Function	Pilot Flying Captain
Qualification	Flight Crew Instrument Flight Crew Multiengine Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Procedural Published Material / Policy Ground Event / Encounter Loss Of Aircraft Control Ground Excursion Taxiway

Narrative:

Routine preflight by right seat pilot. Normal startup. Annunciator panel normal. During prep for taxi and obtaining IFR clearance left seat pilot dropped an ipad on the left armrest and breaker panel area. Didn't think anything of it. Obtained taxi clearance. After leaving the ramp area with left seat pilot taxiing the master caution began to flash followed shortly by the failure of the brakes as we approached a 90 degree right turn on the taxiways. Right seat pilot recognized that the power brake annunciator was lit. Reached across the cockpit to reset the breaker for the brakes. Braking action returned immediately. During the few seconds the brakes were inoperative the airplane got off the edge of the taxiway and into the grass. Grass was pretty smooth; relatively flat and we did not contact any taxi lights or anything else while in the grass. Then saw two pieces of a circuit breaker collar on the armrest that had been on the power brake breaker for years. Knew that the dropped ipad had hit the collar which stood taller than the surrounding breakers; tripping the breaker and breaking the collar. Continued taxi with completely normal brake function so felt no reason to delay the trip. After talking to maintenance the next day decided to replace the breaker. A collar will not be put back on that breaker.

Original NASA ASRS Text

Title: C560 flight crew reported that a dropped iPad broke a circuit breaker collar and tripped the breaker; causing a loss of brake pressure and a taxiway excursion.

Narrative: Routine preflight by right seat pilot. Normal startup. Annunciator panel normal. During prep for taxi and obtaining IFR clearance left seat pilot dropped an iPad on the left armrest and breaker panel area. Didn't think anything of it. Obtained taxi clearance. After leaving the ramp area with left seat pilot taxiing the master caution began to flash followed shortly by the failure of the brakes as we approached a 90 degree right turn on the taxiways. Right seat pilot recognized that the power brake annunciator was lit. Reached across the cockpit to reset the breaker for the brakes. Braking action returned immediately. During the few seconds the brakes were inoperative the airplane got off the edge of the taxiway and into the grass. Grass was pretty smooth; relatively flat and we did not contact any taxi lights or anything else while in the grass. Then saw two pieces of a circuit breaker collar on the armrest that had been on the power brake breaker for years. Knew that the dropped iPad had hit the collar which stood taller than the surrounding breakers; tripping the breaker and breaking the collar. Continued taxi with completely normal brake function so felt no reason to delay the trip. After talking to Maintenance the next day decided to replace the breaker. A collar will NOT be put back on that breaker.

Data retrieved from NASA's ASRS site 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.

C560 flight crew reported that a dropped ipad broke a circuit breaker collar and tripped the breaker; causing a loss of brake pressure and a taxiway excursion.