A BA3201 on approach at 5000 ft declared an emergency due to right brake pressure indicated 500 psi.

Attributes
ACN	499163
Time
Date	200101
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : iad.airport
State Reference	VA
Altitude	msl single value : 5000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : iad.tracon
Operator	common carrier : air carrier
Make Model Name	Jetstream 32
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach
Route In Use	arrival : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi pilot : instrument pilot : multi engine
Experience	flight time last 90 days : 13 flight time total : 3624 flight time type : 1222
ASRS Report	499163
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : multi engine pilot : commercial
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : #2 right brake press ind other flight crewa other flight crewb
Resolutory Action	flight crew : declared emergency flight crew : overcame equipment problem
Consequence	other
Supplementary
Problem Areas	Chart Or Publication Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

During descent into iad, we tested the toe brakes, as directed by the 'descent/approach' checklist. The right brake pressure indication rose to 1000 psi. Upon releasing pressure on the toe brakes, we noted that the right brake pressure indication dropped to 500 psi and remained at that value. There is no QRH procedure to deal with this situation. We contacted maintenance control and described our situation. At maintenance control's suggestion, we first lowered the landing gear and then depressurized the hydraulic system. The right brake pressure indication rose to between 600-700 psi during this process. However, the main brake accumulator pressure dropped to below 500 psi. Maintenance control informed us that they believed we were dealing with a false indication. We repressurized the hydraulic system. As a precaution, we declared an emergency, requested that crash fire rescue equipment await the arrival of the aircraft, and landed without further incident at iad.

Original NASA ASRS Text

Title: A BA3201 ON APCH AT 5000 FT DECLARED AN EMER DUE TO R BRAKE PRESSURE INDICATED 500 PSI.

Narrative: DURING DSCNT INTO IAD, WE TESTED THE TOE BRAKES, AS DIRECTED BY THE 'DSCNT/APCH' CHKLIST. THE R BRAKE PRESSURE INDICATION ROSE TO 1000 PSI. UPON RELEASING PRESSURE ON THE TOE BRAKES, WE NOTED THAT THE R BRAKE PRESSURE INDICATION DROPPED TO 500 PSI AND REMAINED AT THAT VALUE. THERE IS NO QRH PROC TO DEAL WITH THIS SIT. WE CONTACTED MAINT CTL AND DESCRIBED OUR SIT. AT MAINT CTL'S SUGGESTION, WE FIRST LOWERED THE LNDG GEAR AND THEN DEPRESSURIZED THE HYD SYS. THE R BRAKE PRESSURE INDICATION ROSE TO BTWN 600-700 PSI DURING THIS PROCESS. HOWEVER, THE MAIN BRAKE ACCUMULATOR PRESSURE DROPPED TO BELOW 500 PSI. MAINT CTL INFORMED US THAT THEY BELIEVED WE WERE DEALING WITH A FALSE INDICATION. WE REPRESSURIZED THE HYD SYS. AS A PRECAUTION, WE DECLARED AN EMER, REQUESTED THAT CFR AWAIT THE ARR OF THE ACFT, AND LANDED WITHOUT FURTHER INCIDENT AT IAD.

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.