B757 flight crew experiences both landing gear light bulbs in the indicator burn out, so they declar...

Attributes
ACN	571903
Time
Date	200301
Day	Wed
Local Time Of Day	0001 To 0600
Place
Locale Reference	airport : sat.airport
State Reference	TX
Altitude	msl single value : 3000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	tracon : sat.tracon tower : sat.tower
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : approach landing : missed approach
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 100 flight time total : 13000 flight time type : 4000
ASRS Report	571903
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : less severe
Independent Detector	aircraft equipment other aircraft equipment : gear indications other flight crewa other flight crewb
Resolutory Action	flight crew : landed in emergency condition flight crew : executed go around flight crew : declared emergency
Consequence	other
Supplementary
Problem Areas	Aircraft Flight Crew Human Performance
Primary Problem	Aircraft

Narrative:

No indication of left main gear. Lack of additional EICAS message indicated that this is simply a blown light bulb, although a little unlikely, due to the fact that both bulbs would have to coincidentally fail. Unable to resolve gear indication between onset of problem and runway, so a missed approach was performed. Contact with company maintenance was initiated, but radio reception was unusable due to problem with the ground equipment. Several attempts were made to re-establish contact with company maintenance, to no avail. While being vectored by san antonio approach, I noticed that the antenna reception on my cell phone suddenly peaked. We asked approach if we might enter a series of 360 degree turns (over the cell phone ground antenna), which was approved. Contact was made with maintenance via cell phone, and they advised a tower fly-by. Ensuing fly-by indicated that both main gear appeared to be in the same position (still before daylight, and difficult to see), so an emergency was declared, equipment requested, followed by uneventful landing. Trucks followed the aircraft into the ramp, where the main gear was pinned. Maintenance changed both bulbs in the gear indicator, and both bulbs indicated down and locked.

Original NASA ASRS Text

Title: B757 FLT CREW EXPERIENCES BOTH LNDG GEAR LIGHT BULBS IN THE INDICATOR BURN OUT, SO THEY DECLARED AN EMER, BECAUSE THEY WERE UNABLE TO DETERMINE IF THE GEAR WAS DOWN. THEY LANDED UNEVENTFULLY.

Narrative: NO INDICATION OF L MAIN GEAR. LACK OF ADDITIONAL EICAS MESSAGE INDICATED THAT THIS IS SIMPLY A BLOWN LIGHT BULB, ALTHOUGH A LITTLE UNLIKELY, DUE TO THE FACT THAT BOTH BULBS WOULD HAVE TO COINCIDENTALLY FAIL. UNABLE TO RESOLVE GEAR INDICATION BTWN ONSET OF PROB AND RWY, SO A MISSED APCH WAS PERFORMED. CONTACT WITH COMPANY MAINT WAS INITIATED, BUT RADIO RECEPTION WAS UNUSABLE DUE TO PROB WITH THE GND EQUIP. SEVERAL ATTEMPTS WERE MADE TO RE-ESTABLISH CONTACT WITH COMPANY MAINT, TO NO AVAIL. WHILE BEING VECTORED BY SAN ANTONIO APCH, I NOTICED THAT THE ANTENNA RECEPTION ON MY CELL PHONE SUDDENLY PEAKED. WE ASKED APCH IF WE MIGHT ENTER A SERIES OF 360 DEG TURNS (OVER THE CELL PHONE GND ANTENNA), WHICH WAS APPROVED. CONTACT WAS MADE WITH MAINT VIA CELL PHONE, AND THEY ADVISED A TWR FLY-BY. ENSUING FLY-BY INDICATED THAT BOTH MAIN GEAR APPEARED TO BE IN THE SAME POS (STILL BEFORE DAYLIGHT, AND DIFFICULT TO SEE), SO AN EMER WAS DECLARED, EQUIP REQUESTED, FOLLOWED BY UNEVENTFUL LNDG. TRUCKS FOLLOWED THE ACFT INTO THE RAMP, WHERE THE MAIN GEAR WAS PINNED. MAINT CHANGED BOTH BULBS IN THE GEAR INDICATOR, AND BOTH BULBS INDICATED DOWN AND LOCKED.

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.

B757 flight crew experiences both landing gear light bulbs in the indicator burn out, so they declared an emergency, because they were unable to determine if the gear was down. They landed uneventfully.