Flight crew of an medium large transport loses a generator constant speed drive causing failure of 1...

Attributes
ACN	308038
Time
Date	199506
Day	Wed
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : gso
State Reference	NC
Altitude	msl bound lower : 28000 msl bound upper : 28000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc tracon : gso tower : gso
Operator	common carrier : air carrier
Make Model Name	B737-200
Operating Under FAR Part	Part 121
Flight Phase	cruise other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 250 flight time total : 15000 flight time type : 4000
ASRS Report	308038
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : unspecified other flight crewa
Resolutory Action	flight crew : declared emergency other
Consequence	faa : investigated Other
Supplementary
Primary Problem	Aircraft

Narrative:

En route phl-gso, just prior to top of descent, #2 constant speed drive low oil pressure light came on. Disconnected #2 constant speed drive. APU would not start. Advised ATC of 1 generator operation. On approach, after lowering gear observed no green gear lights. Missed approach and requested visual on gear down before landing. Tower verified gear down and I requested emergency equipment upon landing. Landed and taxied to gate. Callback conversation with reporter revealed the following information: reporter stated that the APU would not start because of lack of sufficient dc battery current to start the turbine. He found out after aircraft maintenance examination, that the battery had a 'thermal runaway' apparently due to a faulty regulator. Of course what started the chain reaction was probably the generator constant speed drive failure and the resultant switch over of all electrical power on the 1 generator rather than the supplementation of the APU electrical generator input. This problem caused the gear light outage and other electrical operated indications and system. He further stated that when he began to smell smoke fumes during the landing indication low fly by, he became worried and declared an emergency for an immediate landing. He found later that the smell came from the 'run away' battery. He also stated that the FAA sent him a letter of investigation for possible violation of the far for not writing up the fact that the APU would not start! He is in the process of replying to that letter.

Original NASA ASRS Text

Title: FLC OF AN MLG LOSES A GENERATOR CONSTANT SPD DRIVE CAUSING FAILURE OF 1 GENERATOR AND WAS UNABLE TO START THE APU FOR BACK UP PWR DUE TO A BATTERY THERMAL RUNAWAY.

Narrative: ENRTE PHL-GSO, JUST PRIOR TO TOP OF DSCNT, #2 CONSTANT SPD DRIVE LOW OIL PRESSURE LIGHT CAME ON. DISCONNECTED #2 CONSTANT SPD DRIVE. APU WOULD NOT START. ADVISED ATC OF 1 GENERATOR OP. ON APCH, AFTER LOWERING GEAR OBSERVED NO GREEN GEAR LIGHTS. MISSED APCH AND REQUESTED VISUAL ON GEAR DOWN BEFORE LNDG. TWR VERIFIED GEAR DOWN AND I REQUESTED EMER EQUIP UPON LNDG. LANDED AND TAXIED TO GATE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE APU WOULD NOT START BECAUSE OF LACK OF SUFFICIENT DC BATTERY CURRENT TO START THE TURBINE. HE FOUND OUT AFTER ACFT MAINT EXAMINATION, THAT THE BATTERY HAD A 'THERMAL RUNAWAY' APPARENTLY DUE TO A FAULTY REGULATOR. OF COURSE WHAT STARTED THE CHAIN REACTION WAS PROBABLY THE GENERATOR CONSTANT SPD DRIVE FAILURE AND THE RESULTANT SWITCH OVER OF ALL ELECTRICAL PWR ON THE 1 GENERATOR RATHER THAN THE SUPPLEMENTATION OF THE APU ELECTRICAL GENERATOR INPUT. THIS PROB CAUSED THE GEAR LIGHT OUTAGE AND OTHER ELECTRICAL OPERATED INDICATIONS AND SYS. HE FURTHER STATED THAT WHEN HE BEGAN TO SMELL SMOKE FUMES DURING THE LNDG INDICATION LOW FLY BY, HE BECAME WORRIED AND DECLARED AN EMER FOR AN IMMEDIATE LNDG. HE FOUND LATER THAT THE SMELL CAME FROM THE 'RUN AWAY' BATTERY. HE ALSO STATED THAT THE FAA SENT HIM A LETTER OF INVESTIGATION FOR POSSIBLE VIOLATION OF THE FAR FOR NOT WRITING UP THE FACT THAT THE APU WOULD NOT START! HE IS IN THE PROCESS OF REPLYING TO THAT LETTER.

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.

Flight crew of an medium large transport loses a generator constant speed drive causing failure of 1 generator and was unable to start the APU for back up power due to a battery thermal runaway.