Inadvertent activation of GPWS test sequence on approach. Map executed.

Attributes
ACN	269950
Time
Date	199404
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : san
State Reference	CA
Altitude	msl bound lower : 3800 msl bound upper : 5500
Environment
Flight Conditions	IMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : san
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent : approach landing : go around landing : missed approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : flight engineer pilot : commercial pilot : cfi pilot : atp
Experience	flight time last 90 days : 75 flight time total : 9500 flight time type : 1400
ASRS Report	269950
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : flight engineer pilot : instrument pilot : atp
Experience	flight time last 90 days : 150 flight time total : 5000 flight time type : 1500
ASRS Report	270342
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	aircraft : equipment problem dissipated
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were being vectored for a localizer 27 approach to san. When over swatt intersection, the GPWS sounded 'terrain - terrain' and then 5 seconds later another 'terrain - terrain' warning. The copilot who was flying then initiated a climb maneuver which took us to 5500 ft. During the climb (shortly after go around power was applied), the GPWS sounded 'whoop, whoop -- pull up' twice, then sounded the warning 'GS.' after leveling off at 5500 ft, we coordinated with ATC for vectors for another localizer 27 approach. The second attempt was without incident. I believe we somehow activated the GPWS test sequence and consequently got an entire test warning announcement. We did fly over a 2800 ft mountain, but were in level flight. We were in IMC at the time -- so a climb was required even though we knew that we had adequate terrain clearance at the time.

Original NASA ASRS Text

Title: INADVERTENT ACTIVATION OF GPWS TEST SEQUENCE ON APCH. MAP EXECUTED.

Narrative: WE WERE BEING VECTORED FOR A LOC 27 APCH TO SAN. WHEN OVER SWATT INTXN, THE GPWS SOUNDED 'TERRAIN - TERRAIN' AND THEN 5 SECONDS LATER ANOTHER 'TERRAIN - TERRAIN' WARNING. THE COPLT WHO WAS FLYING THEN INITIATED A CLB MANEUVER WHICH TOOK US TO 5500 FT. DURING THE CLB (SHORTLY AFTER GAR PWR WAS APPLIED), THE GPWS SOUNDED 'WHOOP, WHOOP -- PULL UP' TWICE, THEN SOUNDED THE WARNING 'GS.' AFTER LEVELING OFF AT 5500 FT, WE COORDINATED WITH ATC FOR VECTORS FOR ANOTHER LOC 27 APCH. THE SECOND ATTEMPT WAS WITHOUT INCIDENT. I BELIEVE WE SOMEHOW ACTIVATED THE GPWS TEST SEQUENCE AND CONSEQUENTLY GOT AN ENTIRE TEST WARNING ANNOUNCEMENT. WE DID FLY OVER A 2800 FT MOUNTAIN, BUT WERE IN LEVEL FLT. WE WERE IN IMC AT THE TIME -- SO A CLB WAS REQUIRED EVEN THOUGH WE KNEW THAT WE HAD ADEQUATE TERRAIN CLRNC AT THE TIME.

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.