B737-400 loses dc power to IRS system. Diverts to nearby airport.

Attributes
ACN	807641
Time
Date	200810
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : zjx.artcc
State Reference	FL
Altitude	msl single value : 34000
Environment
Flight Conditions	VMC
Weather Elements	other
Light	Night
Aircraft 1
Controlling Facilities	artcc : zjx.artcc
Operator	common carrier : air carrier
Make Model Name	B737-400
Operating Under FAR Part	Part 121
Flight Phase	cruise : level
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	807641
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : irs dc fail lights other flight crewa
Resolutory Action	flight crew : diverted to another airport
Supplementary
Problem Areas	Aircraft
Primary Problem	Aircraft

Narrative:

Cruise FL340; noticed battery voltage drop at approximately 20 volts both dc fail lights illuminated on IRS. Checked with and complied with QRH. Contacted dispatch who called maintenance; then company. Dispatch asked for diversion to ZZZ. Advised ATC; flight attendants; and passenger. Landed ZZZ. Changed aircraft; went to destination.

Original NASA ASRS Text

Title: B737-400 LOSES DC POWER TO IRS SYSTEM. DIVERTS TO NEARBY ARPT.

Narrative: CRUISE FL340; NOTICED BATTERY VOLTAGE DROP AT APPROX 20 VOLTS BOTH DC FAIL LIGHTS ILLUMINATED ON IRS. CHKED WITH AND COMPLIED WITH QRH. CONTACTED DISPATCH WHO CALLED MAINT; THEN COMPANY. DISPATCH ASKED FOR DIVERSION TO ZZZ. ADVISED ATC; FLT ATTENDANTS; AND PAX. LANDED ZZZ. CHANGED ACFT; WENT TO DEST.

Data retrieved from NASA's ASRS site as of May 2009 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.