E145 crew had APU failure and smoke and electrical odor in the cabin.

Attributes
ACN	518595
Time
Date	200107
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : pit.airport
State Reference	PA
Altitude	msl single value : 6500
Environment
Flight Conditions	Mixed
Light	Dusk
Aircraft 1
Controlling Facilities	tracon : pit.tracon tower : ric.tower
Operator	common carrier : air carrier
Make Model Name	EMB ERJ 145 ER&LR
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
Experience	flight time last 90 days : 270 flight time total : 5000 flight time type : 2500
ASRS Report	518595
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	aircraft equipment problem : critical other anomaly other anomaly
Independent Detector	aircraft equipment other aircraft equipment : eicas, master caution other flight crewa other flight crewb
Resolutory Action	controller : issued new clearance flight crew : declared emergency flight crew : landed in emergency condition flight crew : diverted to another airport
Consequence	other other
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Descending into pit area, through approximately 6500 ft, an APU fail message appeared on EICAS followed by a master caution bell. Shortly after APU failure indication, a strong burnt electrical odor and slight pressure of smoke was noticed. We immediately pulled the emergency checklist for electrical system smoke or fire. Followed checklist and secured APU and related items. ATC was notified of situation. ATC declared an emergency for us and gave us vectors direct to the airport for a visual approach. Once APU was secured, odor and smoke dissipated quickly. Aircraft was landed without incident and taxied to ramp area. Maintenance was notified of problem, as well as iah base chief pilot. After evaluating situation, I have come to the conclusion that the APU generator control unit had overheated and failed. The odor and small amount of smoke made me believe APU failed and aircraft logic removed power to unit before it became a bigger problem. Avoidance of this incident could have only been by non operation of APU in air.

Original NASA ASRS Text

Title: E145 CREW HAD APU FAILURE AND SMOKE AND ELECTRICAL ODOR IN THE CABIN.

Narrative: DSNDING INTO PIT AREA, THROUGH APPROX 6500 FT, AN APU FAIL MESSAGE APPEARED ON EICAS FOLLOWED BY A MASTER CAUTION BELL. SHORTLY AFTER APU FAILURE INDICATION, A STRONG BURNT ELECTRICAL ODOR AND SLIGHT PRESSURE OF SMOKE WAS NOTICED. WE IMMEDIATELY PULLED THE EMER CHKLIST FOR ELECTRICAL SYS SMOKE OR FIRE. FOLLOWED CHKLIST AND SECURED APU AND RELATED ITEMS. ATC WAS NOTIFIED OF SIT. ATC DECLARED AN EMER FOR US AND GAVE US VECTORS DIRECT TO THE ARPT FOR A VISUAL APCH. ONCE APU WAS SECURED, ODOR AND SMOKE DISSIPATED QUICKLY. ACFT WAS LANDED WITHOUT INCIDENT AND TAXIED TO RAMP AREA. MAINT WAS NOTIFIED OF PROB, AS WELL AS IAH BASE CHIEF PLT. AFTER EVALUATING SIT, I HAVE COME TO THE CONCLUSION THAT THE APU GENERATOR CTL UNIT HAD OVERHEATED AND FAILED. THE ODOR AND SMALL AMOUNT OF SMOKE MADE ME BELIEVE APU FAILED AND ACFT LOGIC REMOVED PWR TO UNIT BEFORE IT BECAME A BIGGER PROB. AVOIDANCE OF THIS INCIDENT COULD HAVE ONLY BEEN BY NON OP OF APU IN AIR.

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.