B737-800 crew executed an egpws escape maneuver with an emergency maximum rate climb until the warni...

Attributes
ACN	544005
Time
Date	200204
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : gum.airport
State Reference	GU
Altitude	msl single value : 2000
Environment
Weather Elements	other
Light	Night
Aircraft 1
Controlling Facilities	tower : gum.tower tower : hou&.tower
Operator	common carrier : air carrier
Make Model Name	B737-800
Operating Under FAR Part	Part 121
Navigation In Use	ils localizer & glide slope : 6l other other Other
Flight Phase	descent : approach
Route In Use	approach : instrument precision
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 184.43 flight time total : 12000 flight time type : 184.43
ASRS Report	544005
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	inflight encounter : weather inflight encounter other other anomaly other
Independent Detector	aircraft equipment : gpws other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : took evasive action flight crew : executed missed approach none taken : detected after the fact other
Supplementary
Problem Areas	Aircraft ATC Human Performance FAA Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

After radar contact inbound to pgum on airway B586, ATC cleared us direct to the unz VOR and issued us a pilot's discretion descent clearance to 2000 ft. After crossing the guam shoreline descending through approximately 2400 ft, the GPWS announced a 'caution terrain' message. After leveling at 2000 ft, the GPWS announced a 'pull up, terrain' command. As we executed the pull up maneuver, ATC simultaneously issued us a clearance to turn left to a heading of 030 degrees and to climb to 2600 ft for vectors to the ILS runway 6L approach as we had not yet sighted the airport. We then flew the ILS runway 6L approach and landed. At the time of the GPWS activation, we were configured with flaps 5 degrees at the flaps 5 maneuvering speed with the landing gear retracted. The MVA of 2000 ft on this routing appears to be insufficient to prevent a GPWS activation. Suggest MVA altitudes be high enough to avoid GPWS activation. Even though the 2000 foot altitude assigned clears all terrain, it was insufficient to avoid GPWS activation in this instance. Callback conversation with reporter revealed the following information: the captain's aircraft was equipped with dual GPS receivers updating dual FMC's and triple IRU's. Also the aircraft has dual egpws systems with dual radio altimeter inputs. In short the latest and most sophisticated system it is possible to have. There was no evidence of any type of map shift. The approach was being flown at night entering the airport area from the ssw. The island area from this direction is a 'black hole' with no ground lights. When the egpws terrain warning sounded the crew followed the emergency procedure and began an emergency climb. He stated that this will really get your heart started. The captain reported the results of the company safety investigation as the minimum vectoring altitude is below the altitude that will cause the egpws to alarm. He strongly suggests the minimum vectoring altitude be raised so as to be compatible with the egpws system.

Original NASA ASRS Text

Title: B737-800 CREW EXECUTED AN EGPWS ESCAPE MANEUVER WITH AN EMER MAX RATE CLB UNTIL THE WARNING STOPPED. ACFT WAS ABOVE THE MINIMUM VECTORING ALT AT THE TIME OF OCCURRENCE.

Narrative: AFTER RADAR CONTACT INBOUND TO PGUM ON AIRWAY B586, ATC CLRED US DIRECT TO THE UNZ VOR AND ISSUED US A PLT'S DISCRETION DSCNT CLRNC TO 2000 FT. AFTER XING THE GUAM SHORELINE DSNDING THROUGH APPROX 2400 FT, THE GPWS ANNOUNCED A 'CAUTION TERRAIN' MSG. AFTER LEVELING AT 2000 FT, THE GPWS ANNOUNCED A 'PULL UP, TERRAIN' COMMAND. AS WE EXECUTED THE PULL UP MANEUVER, ATC SIMULTANEOUSLY ISSUED US A CLRNC TO TURN LEFT TO A HEADING OF 030 DEGS AND TO CLB TO 2600 FT FOR VECTORS TO THE ILS RWY 6L APCH AS WE HAD NOT YET SIGHTED THE ARPT. WE THEN FLEW THE ILS RWY 6L APCH AND LANDED. AT THE TIME OF THE GPWS ACTIVATION, WE WERE CONFIGURED WITH FLAPS 5 DEGS AT THE FLAPS 5 MANEUVERING SPEED WITH THE LNDG GEAR RETRACTED. THE MVA OF 2000 FT ON THIS ROUTING APPEARS TO BE INSUFFICIENT TO PREVENT A GPWS ACTIVATION. SUGGEST MVA ALTITUDES BE HIGH ENOUGH TO AVOID GPWS ACTIVATION. EVEN THOUGH THE 2000 FOOT ALTITUDE ASSIGNED CLRS ALL TERRAIN, IT WAS INSUFFICIENT TO AVOID GPWS ACTIVATION IN THIS INSTANCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAPT'S ACFT WAS EQUIPPED WITH DUAL GPS RECEIVERS UPDATING DUAL FMC'S AND TRIPLE IRU'S. ALSO THE ACFT HAS DUAL EGPWS SYSTEMS WITH DUAL RADIO ALTIMETER INPUTS. IN SHORT THE LATEST AND MOST SOPHISTICATED SYSTEM IT IS POSSIBLE TO HAVE. THERE WAS NO EVIDENCE OF ANY TYPE OF MAP SHIFT. THE APCH WAS BEING FLOWN AT NIGHT ENTERING THE ARPT AREA FROM THE SSW. THE ISLAND AREA FROM THIS DIRECTION IS A 'BLACK HOLE' WITH NO GND LIGHTS. WHEN THE EGPWS TERRAIN WARNING SOUNDED THE CREW FOLLOWED THE EMER PROC AND BEGAN AN EMER CLB. HE STATED THAT THIS WILL REALLY GET YOUR HEART STARTED. THE CAPT RPTED THE RESULTS OF THE COMPANY SAFETY INVESTIGATION AS THE MINIMUM VECTORING ALT IS BELOW THE ALT THAT WILL CAUSE THE EGPWS TO ALARM. HE STRONGLY SUGGESTS THE MINIMUM VECTORING ALT BE RAISED SO AS TO BE COMPATIBLE WITH THE EGPWS SYSTEM.

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.

B737-800 crew executed an egpws escape maneuver with an emergency maximum rate climb until the warning stopped. Aircraft was above the minimum vectoring altitude at the time of occurrence.