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At FL200 outside air temperature -15 degrees centigrade left windshield of 2 engine turboprop cracked outer pane.
| Attributes | |
| ACN | 127687 |
| Time | |
| Date | 198911 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : pih |
| State Reference | ID |
| Altitude | msl bound lower : 20000 msl bound upper : 20000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc |
| Operator | general aviation : personal |
| Make Model Name | Small Transport, Low Wing, 2 Turboprop Eng |
| Navigation In Use | Other |
| Flight Phase | other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : single pilot |
| Qualification | pilot : atp pilot : commercial pilot : instrument |
| Experience | flight time last 90 days : 150 flight time total : 2265 flight time type : 200 |
| ASRS Report | 127687 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : less severe other anomaly other |
| Independent Detector | other other : unspecified cockpit |
| Resolutory Action | flight crew : overcame equipment problem other |
| Consequence | other Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
At approximately xa hours in nov/89, I, as the pilot, and one passenger, departed idaho falls, identification. After departure, a left turn out was performed and clearance was obtained from salt lake city center for an IFR flight plan return to salt lake city. On climbout, windshield anti-ice was used as we came up through several cloud layers. Upon reaching FL200 and upon leveling off, we were free of clouds. As airspeed was building and prior to reducing the propeller RPM, 'a loud pop' was heard. At that time, it was noted that extensive fractures had developed in the external panel of the left (pilot's) windshield. These appeared to have been in 2 vertical areas (one beneath the windshield wiper and one approximately 2' laterally). From these multiple vertical cracks, horizontal cracks were then noted, from the top of the windshield to the bottom of the windshield. There did not appear to be any pieces of the windshield missing. No loss of pressurization was noted to occur. Due to the sudden change in events, I declared an emergency through ATC and we were diverted to pocatello which was now at 270 degree and 35 mi from our present position. The crack was noted to occur at FL200 where the temperature was -15 degree centigrade. An uneventful emergency descent and landing at pocatello was carried out. I was able to visualize the landing environment through the multiple fractures in the external pane.
Original NASA ASRS Text
Title: AT FL200 OUTSIDE AIR TEMPERATURE -15 DEGREES CENTIGRADE LEFT WINDSHIELD OF 2 ENGINE TURBOPROP CRACKED OUTER PANE.
Narrative: AT APPROX XA HOURS IN NOV/89, I, AS THE PLT, AND ONE PAX, DEPARTED IDAHO FALLS, ID. AFTER DEP, A LEFT TURN OUT WAS PERFORMED AND CLRNC WAS OBTAINED FROM SALT LAKE CITY CENTER FOR AN IFR FLT PLAN RETURN TO SALT LAKE CITY. ON CLIMBOUT, WINDSHIELD ANTI-ICE WAS USED AS WE CAME UP THROUGH SEVERAL CLOUD LAYERS. UPON REACHING FL200 AND UPON LEVELING OFF, WE WERE FREE OF CLOUDS. AS AIRSPEED WAS BUILDING AND PRIOR TO REDUCING THE PROPELLER RPM, 'A LOUD POP' WAS HEARD. AT THAT TIME, IT WAS NOTED THAT EXTENSIVE FRACTURES HAD DEVELOPED IN THE EXTERNAL PANEL OF THE LEFT (PLT'S) WINDSHIELD. THESE APPEARED TO HAVE BEEN IN 2 VERTICAL AREAS (ONE BENEATH THE WINDSHIELD WIPER AND ONE APPROX 2' LATERALLY). FROM THESE MULTIPLE VERTICAL CRACKS, HORIZONTAL CRACKS WERE THEN NOTED, FROM THE TOP OF THE WINDSHIELD TO THE BOTTOM OF THE WINDSHIELD. THERE DID NOT APPEAR TO BE ANY PIECES OF THE WINDSHIELD MISSING. NO LOSS OF PRESSURIZATION WAS NOTED TO OCCUR. DUE TO THE SUDDEN CHANGE IN EVENTS, I DECLARED AN EMER THROUGH ATC AND WE WERE DIVERTED TO POCATELLO WHICH WAS NOW AT 270 DEG AND 35 MI FROM OUR PRESENT POSITION. THE CRACK WAS NOTED TO OCCUR AT FL200 WHERE THE TEMPERATURE WAS -15 DEG CENTIGRADE. AN UNEVENTFUL EMER DSCNT AND LNDG AT POCATELLO WAS CARRIED OUT. I WAS ABLE TO VISUALIZE THE LNDG ENVIRONMENT THROUGH THE MULTIPLE FRACTURES IN THE EXTERNAL PANE.
Data retrieved from NASA's ASRS site as of August 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.