A window blew out of a pressurized light transport requiring an emergency descent.

Attributes
ACN	233373
Time
Date	199302
Day	Fri
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : pia
State Reference	IL
Altitude	msl bound lower : 19700 msl bound upper : 19700
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zau
Operator	general aviation : personal
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	climbout : intermediate altitude descent other other
Flight Plan	IFR
Person 1
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : commercial pilot : instrument
Experience	flight time last 90 days : 55 flight time total : 1000 flight time type : 35
ASRS Report	233373
Person 2
Affiliation	Other
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa other other : unspecified
Resolutory Action	controller : issued new clearance flight crew : declared emergency flight crew : exited adverse environment
Consequence	Other
Supplementary
Primary Problem	Aircraft

Narrative:

We were cleared to our final cruising altitude of FL200. As we neared that altitude, there was a loud bang in the aft of the aircraft. Quickly there was depressurization of the cabin. Passenger reported a broken passenger window and the decision was made to quickly descend to a level where the aircraft and passenger would be safer. As in our training, we descended in a 30 degree bank and about 4000-5000 FPM and alerted center we needed lower because of a broken window and depressurization. From the cockpit it was not known how extensive the damage was, but we monitored the instruments and saw no other irregularities. ATC asked us our intentions and we asked to return to our departure airport. The controller asked if we were in an emergency. The other pilot was handling the radio and said 'not at this time.' we definitely took emergency action. There was little radio discussion during our initial handling of the situation and we did not formally declare an emergency. In retrospect, we probably should have specifically stated mayday. However, after things were stabilized, we were likely not in an emergency situation. Cause of the window failure is unknown.

Original NASA ASRS Text

Title: A WINDOW BLEW OUT OF A PRESSURIZED LTT REQUIRING AN EMER DSCNT.

Narrative: WE WERE CLRED TO OUR FINAL CRUISING ALT OF FL200. AS WE NEARED THAT ALT, THERE WAS A LOUD BANG IN THE AFT OF THE ACFT. QUICKLY THERE WAS DEPRESSURIZATION OF THE CABIN. PAX RPTED A BROKEN PAX WINDOW AND THE DECISION WAS MADE TO QUICKLY DSND TO A LEVEL WHERE THE ACFT AND PAX WOULD BE SAFER. AS IN OUR TRAINING, WE DSNDED IN A 30 DEG BANK AND ABOUT 4000-5000 FPM AND ALERTED CTR WE NEEDED LOWER BECAUSE OF A BROKEN WINDOW AND DEPRESSURIZATION. FROM THE COCKPIT IT WAS NOT KNOWN HOW EXTENSIVE THE DAMAGE WAS, BUT WE MONITORED THE INSTS AND SAW NO OTHER IRREGULARITIES. ATC ASKED US OUR INTENTIONS AND WE ASKED TO RETURN TO OUR DEP ARPT. THE CTLR ASKED IF WE WERE IN AN EMER. THE OTHER PLT WAS HANDLING THE RADIO AND SAID 'NOT AT THIS TIME.' WE DEFINITELY TOOK EMER ACTION. THERE WAS LITTLE RADIO DISCUSSION DURING OUR INITIAL HANDLING OF THE SIT AND WE DID NOT FORMALLY DECLARE AN EMER. IN RETROSPECT, WE PROBABLY SHOULD HAVE SPECIFICALLY STATED MAYDAY. HOWEVER, AFTER THINGS WERE STABILIZED, WE WERE LIKELY NOT IN AN EMER SIT. CAUSE OF THE WINDOW FAILURE IS UNKNOWN.

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.