A B737-300 in climb experienced the right inertial reference unit failure causing complete loss of the first officer's flight instruments with no ability to switch to the captain's inertial reference unit.

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Attributes
ACN	376424
Time
Date	199708
Day	Wed
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : abq
State Reference	NM
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zab
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : cfi
Experience	flight time last 90 days : 200 flight time total : 20000 flight time type : 4000
ASRS Report	376424
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	other flight crewa other other : unspecified cockpit
Resolutory Action	none taken : unable
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Approximately 10 mins after departure, right inertial reference unit failed causing the loss of the right side ADI, HSI, autoplt and left side RMI. This airplane had no xfer switch to share the left inertial reference unit's signal with the lost instruments as do certain other aircraft in our fleet. This caused the left seat pilot to have to hand fly the aircraft in IMC conditions for almost 2 hours without much help from the copilot. This was the sixth inertial reference unit write-up in the past few days. I believe there needs to be a serious look at how maintenance responded to these failures. I also believe that there should be inertial reference unit xfer switches in all inertial reference unit equipped aircraft.

Original NASA ASRS Text

Title: A B737-300 IN CLB EXPERIENCED THE R INERTIAL REF UNIT FAILURE CAUSING COMPLETE LOSS OF THE FO'S FLT INSTS WITH NO ABILITY TO SWITCH TO THE CAPT'S INERTIAL REF UNIT.

Narrative: APPROX 10 MINS AFTER DEP, R INERTIAL REF UNIT FAILED CAUSING THE LOSS OF THE R SIDE ADI, HSI, AUTOPLT AND L SIDE RMI. THIS AIRPLANE HAD NO XFER SWITCH TO SHARE THE L INERTIAL REF UNIT'S SIGNAL WITH THE LOST INSTS AS DO CERTAIN OTHER ACFT IN OUR FLEET. THIS CAUSED THE L SEAT PLT TO HAVE TO HAND FLY THE ACFT IN IMC CONDITIONS FOR ALMOST 2 HRS WITHOUT MUCH HELP FROM THE COPLT. THIS WAS THE SIXTH INERTIAL REF UNIT WRITE-UP IN THE PAST FEW DAYS. I BELIEVE THERE NEEDS TO BE A SERIOUS LOOK AT HOW MAINT RESPONDED TO THESE FAILURES. I ALSO BELIEVE THAT THERE SHOULD BE INERTIAL REF UNIT XFER SWITCHES IN ALL INERTIAL REF UNIT EQUIPPED ACFT.

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.