C500. Aircraft brakes failed resulted in aircraft departing taxiway.

Attributes
ACN	413850
Time
Date	199809
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : pah
State Reference	KY
Altitude	agl bound lower : 0 agl bound upper : 0
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : corporate
Make Model Name	Citation I
Operating Under FAR Part	Part 91
Flight Phase	ground other : taxi
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 23500 flight time type : 3500
ASRS Report	413850
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical other anomaly other anomaly other other anomaly other
Independent Detector	other flight crewa
Resolutory Action	none taken : insufficient time
Consequence	other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

During taxi, brakes failed in both anti-skid power and manual position. Aircraft exited taxiway to left side. Aircraft was controled by use of left throttle to turn aircraft during excursion off of runway. Extremely minor damage was done to underside of aircraft wing and flap. Airframe is undergoing repairs to wing and flap. Brakes are being evaluated this time. The anti-skid add on, is approved and supplied by a company by the name of 'crane.' I question if this style of brakes should be used on other aircraft of this type. Callback conversation with reporter revealed the following information: the aircraft, a cessna citation 500 has no nosewheel steering. At taxi speed the only directional control the aircraft has is differential brakes. When total brake failure occurred the aircraft had no directional control. The aircraft was modified with an after market stc aircraft brake anti-skid system. This system utilizes a hydraulic shuttle valve to direct system pressure from either the anti-skid system or the normal brake system. If this shuttle valve fails in an intermediate position, both system are ported to return, thus triggering a complete brake system failure. The after market vendor is 'crane,' and the stc number is sa 2025 we. The pilot is concerned that this modification may also be retrofitted on to other aircraft of this type and that they could have the same problem. Crane may have gone out of business. The stc is now owned by 'hydraulics unlimited.'

Original NASA ASRS Text

Title: C500. ACFT BRAKES FAILED RESULTED IN ACFT DEPARTING TXWY.

Narrative: DURING TAXI, BRAKES FAILED IN BOTH ANTI-SKID PWR AND MANUAL POS. ACFT EXITED TXWY TO L SIDE. ACFT WAS CTLED BY USE OF L THROTTLE TO TURN ACFT DURING EXCURSION OFF OF RWY. EXTREMELY MINOR DAMAGE WAS DONE TO UNDERSIDE OF ACFT WING AND FLAP. AIRFRAME IS UNDERGOING REPAIRS TO WING AND FLAP. BRAKES ARE BEING EVALUATED THIS TIME. THE ANTI-SKID ADD ON, IS APPROVED AND SUPPLIED BY A COMPANY BY THE NAME OF 'CRANE.' I QUESTION IF THIS STYLE OF BRAKES SHOULD BE USED ON OTHER ACFT OF THIS TYPE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE ACFT, A CESSNA CITATION 500 HAS NO NOSEWHEEL STEERING. AT TAXI SPD THE ONLY DIRECTIONAL CTL THE ACFT HAS IS DIFFERENTIAL BRAKES. WHEN TOTAL BRAKE FAILURE OCCURRED THE ACFT HAD NO DIRECTIONAL CTL. THE ACFT WAS MODIFIED WITH AN AFTER MARKET STC ACFT BRAKE ANTI-SKID SYS. THIS SYS UTILIZES A HYD SHUTTLE VALVE TO DIRECT SYS PRESSURE FROM EITHER THE ANTI-SKID SYS OR THE NORMAL BRAKE SYS. IF THIS SHUTTLE VALVE FAILS IN AN INTERMEDIATE POS, BOTH SYS ARE PORTED TO RETURN, THUS TRIGGERING A COMPLETE BRAKE SYS FAILURE. THE AFTER MARKET VENDOR IS 'CRANE,' AND THE STC NUMBER IS SA 2025 WE. THE PLT IS CONCERNED THAT THIS MODIFICATION MAY ALSO BE RETROFITTED ON TO OTHER ACFT OF THIS TYPE AND THAT THEY COULD HAVE THE SAME PROB. CRANE MAY HAVE GONE OUT OF BUSINESS. THE STC IS NOW OWNED BY 'HYDRAULICS UNLIMITED.'

Data retrieved from NASA's ASRS site as of July 2007 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.