Emb-145 window heat failed during flight. Flight crew followed procedure to deal with anomaly; but d...

Attributes
ACN	748644
Time
Date	200706
Local Time Of Day	1801 To 2400
Place
Locale Reference	navaid : mgw.vortac
State Reference	WV
Altitude	msl single value : 20000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zdc.artcc
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 : vacating altitude
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Experience	flight time last 90 days : 240 flight time total : 80 flight time type : 5000
ASRS Report	748644
Events
Anomaly	aircraft equipment problem : less severe other anomaly other
Independent Detector	aircraft equipment other aircraft equipment : eicas other flight crewa
Resolutory Action	flight crew : overcame equipment problem
Supplementary
Problem Areas	Aircraft Chart Or Publication
Primary Problem	Chart Or Publication

Narrative:

During descent; 'WS1 heat fail' EICAS caution activated. Message cleared; then reactivated; then cleared several times; then illuminated steady. In attempting to run the QRH procedure; it was discovered that it was written so ambiguously as to be of no help whatsoever. Indeed; it introduced a significant measure of uncertainty regarding what the proper course of action should be. We interpreted it to the best of our ability and did what we thought was best; given the inadequate guidance. Callback conversation with reporter revealed the following information: reporter stated that the procedure specifies that the window heat switch be turned off for 15 second; then back on. If the EICAS message persists; power should be removed from the associated bus after landing. Did the condition refer to the presence of an EICAS message with the switch on or off? He stated that the airline is contacting the manufacturer for clarification.

Original NASA ASRS Text

Title: EMB-145 WINDOW HEAT FAILED DURING FLT. FLT CREW FOLLOWED PROCEDURE TO DEAL WITH ANOMALY; BUT DISCOVERED THE PROCEDURE TO BE AMBIGUOUS.

Narrative: DURING DSCNT; 'WS1 HEAT FAIL' EICAS CAUTION ACTIVATED. MESSAGE CLRED; THEN REACTIVATED; THEN CLRED SEVERAL TIMES; THEN ILLUMINATED STEADY. IN ATTEMPTING TO RUN THE QRH PROC; IT WAS DISCOVERED THAT IT WAS WRITTEN SO AMBIGUOUSLY AS TO BE OF NO HELP WHATSOEVER. INDEED; IT INTRODUCED A SIGNIFICANT MEASURE OF UNCERTAINTY REGARDING WHAT THE PROPER COURSE OF ACTION SHOULD BE. WE INTERPED IT TO THE BEST OF OUR ABILITY AND DID WHAT WE THOUGHT WAS BEST; GIVEN THE INADEQUATE GUIDANCE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THAT THE PROCEDURE SPECIFIES THAT THE WINDOW HEAT SWITCH BE TURNED OFF FOR 15 SEC; THEN BACK ON. IF THE EICAS MSG PERSISTS; POWER SHOULD BE REMOVED FROM THE ASSOCIATED BUS AFTER LNDG. DID THE CONDITION REFER TO THE PRESENCE OF AN EICAS MSG WITH THE SWITCH ON OR OFF? HE STATED THAT THE AIRLINE IS CONTACTING THE MANUFACTURER FOR CLARIFICATION.

Data retrieved from NASA's ASRS site as of January 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.

Emb-145 window heat failed during flight. Flight crew followed procedure to deal with anomaly; but discovered the procedure to be ambiguous.