Narrative:

Note: much of this report is via hearsay. Early in the weekend a captain (his name is known to me) flying an EMB120 noticed a loud hissing sound in the cockpit. He traced the hissing to the area between the side and front windows. Further investigation showed the main support post (an 'I' bean approximately 2 inches by 2 inches and 2 1/2 ft high) was broken. The captain told his first officer that they needed to get the airplane on the ground quickly. I heard about this incident through the grapevine. I was also told that the post was broken clear through in 2 places. And the aircraft skin was ruptured. I am reluctant to follow up on this much on my own (because of very troubled pilot-management relations). But I have independently verified several things. The airplane was one of the first E-120's built. The outer skin had a previous (embraer approved and not uncommon) repair that failed and the post also had failed. They were waiting for a replacement post. The airplane should be flying again in a couple of days. I am concerned about this for several reasons: while I am not an aviation engineer, this post appears to be very important structurally. There are 3 components that hold the top of the window frame to the bottom. These are the outer skin (ruptured), the post (broken completely), and the inner doubler (condition unknown). If all 3 were to break when the aircraft was pressurized I would expect a catastrophic failure in a very short order. I would expect that unpressurized, the aircraft would probably stay together long enough to land. Now my second concern: I believe the company will under report the incident. If it is as serious as I believe, a complete report will initiate major airframe inspections. My company is too cheap and short sighted to want that. Also if repair of the skin (lower corner of the front window frame) is not uncommon, then maybe the stress there is greater than expected. This would indicate greater than expected stress on the window post. Therefore this post should be inspected regularly and or replaced (assuming my base assumption that this post is structurally important is correct). Since I wrote the above I have learned several more details, and confirmed almost everything. The incident flight was from rdd to sfo. The flight landed at sfo, so there was no landing short of the intended airport (but I don't know when the failure occurred). The write up was 'main frame in front of captain's (direct vision, or side window) cracked with associated pressure leak.' the airplane was ferried unpressurized later that day to our maintenance base in XXX. Apparently no interim repair was made before ferrying the aircraft. Per the ferry flight first officer, the general feeling from 'maintenance' was that within 10 more mins of pressurized flight the aircraft would have suffered a catastrophic failure. Callback conversation with reporter revealed the following information: reporter stated that she was concerned about this matter because of being a captain on this same type of equipment and that the company she works for may not follow through effectively in reports to the FAA and the aircraft manufacturer. She further learned that the cause of the support beam failure was due to corrosion. The aircraft fuselage frame member had completely corroded through causing failure to the outside skin repair. The only thing holding the structure together was the inside doubler! She reiterated the need for a special inspection on this type of aircraft to determine if there are indications of problems, in particularly, the older produced aircraft. This aircraft was apparently one of the first few built! She is aware of other aircraft having similar outside skin repairs.

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Original NASA ASRS Text

Title: CAPT OF AN EMB120 RPTS AIRFRAME STRUCTURAL FAILURE NEAR THE CAPT'S WINDSHIELD OPERATED BY ANOTHER FLC.

Narrative: NOTE: MUCH OF THIS RPT IS VIA HEARSAY. EARLY IN THE WEEKEND A CAPT (HIS NAME IS KNOWN TO ME) FLYING AN EMB120 NOTICED A LOUD HISSING SOUND IN THE COCKPIT. HE TRACED THE HISSING TO THE AREA BTWN THE SIDE AND FRONT WINDOWS. FURTHER INVESTIGATION SHOWED THE MAIN SUPPORT POST (AN 'I' BEAN APPROX 2 INCHES BY 2 INCHES AND 2 1/2 FT HIGH) WAS BROKEN. THE CAPT TOLD HIS FO THAT THEY NEEDED TO GET THE AIRPLANE ON THE GND QUICKLY. I HEARD ABOUT THIS INCIDENT THROUGH THE GRAPEVINE. I WAS ALSO TOLD THAT THE POST WAS BROKEN CLR THROUGH IN 2 PLACES. AND THE ACFT SKIN WAS RUPTURED. I AM RELUCTANT TO FOLLOW UP ON THIS MUCH ON MY OWN (BECAUSE OF VERY TROUBLED PLT-MGMNT RELATIONS). BUT I HAVE INDEPENDENTLY VERIFIED SEVERAL THINGS. THE AIRPLANE WAS ONE OF THE FIRST E-120'S BUILT. THE OUTER SKIN HAD A PREVIOUS (EMBRAER APPROVED AND NOT UNCOMMON) REPAIR THAT FAILED AND THE POST ALSO HAD FAILED. THEY WERE WAITING FOR A REPLACEMENT POST. THE AIRPLANE SHOULD BE FLYING AGAIN IN A COUPLE OF DAYS. I AM CONCERNED ABOUT THIS FOR SEVERAL REASONS: WHILE I AM NOT AN AVIATION ENGINEER, THIS POST APPEARS TO BE VERY IMPORTANT STRUCTURALLY. THERE ARE 3 COMPONENTS THAT HOLD THE TOP OF THE WINDOW FRAME TO THE BOTTOM. THESE ARE THE OUTER SKIN (RUPTURED), THE POST (BROKEN COMPLETELY), AND THE INNER DOUBLER (CONDITION UNKNOWN). IF ALL 3 WERE TO BREAK WHEN THE ACFT WAS PRESSURIZED I WOULD EXPECT A CATASTROPHIC FAILURE IN A VERY SHORT ORDER. I WOULD EXPECT THAT UNPRESSURIZED, THE ACFT WOULD PROBABLY STAY TOGETHER LONG ENOUGH TO LAND. NOW MY SECOND CONCERN: I BELIEVE THE COMPANY WILL UNDER RPT THE INCIDENT. IF IT IS AS SERIOUS AS I BELIEVE, A COMPLETE RPT WILL INITIATE MAJOR AIRFRAME INSPECTIONS. MY COMPANY IS TOO CHEAP AND SHORT SIGHTED TO WANT THAT. ALSO IF REPAIR OF THE SKIN (LOWER CORNER OF THE FRONT WINDOW FRAME) IS NOT UNCOMMON, THEN MAYBE THE STRESS THERE IS GREATER THAN EXPECTED. THIS WOULD INDICATE GREATER THAN EXPECTED STRESS ON THE WINDOW POST. THEREFORE THIS POST SHOULD BE INSPECTED REGULARLY AND OR REPLACED (ASSUMING MY BASE ASSUMPTION THAT THIS POST IS STRUCTURALLY IMPORTANT IS CORRECT). SINCE I WROTE THE ABOVE I HAVE LEARNED SEVERAL MORE DETAILS, AND CONFIRMED ALMOST EVERYTHING. THE INCIDENT FLIGHT WAS FROM RDD TO SFO. THE FLT LANDED AT SFO, SO THERE WAS NO LNDG SHORT OF THE INTENDED ARPT (BUT I DON'T KNOW WHEN THE FAILURE OCCURRED). THE WRITE UP WAS 'MAIN FRAME IN FRONT OF CAPT'S (DIRECT VISION, OR SIDE WINDOW) CRACKED WITH ASSOCIATED PRESSURE LEAK.' THE AIRPLANE WAS FERRIED UNPRESSURIZED LATER THAT DAY TO OUR MAINT BASE IN XXX. APPARENTLY NO INTERIM REPAIR WAS MADE BEFORE FERRYING THE ACFT. PER THE FERRY FLT FO, THE GENERAL FEELING FROM 'MAINT' WAS THAT WITHIN 10 MORE MINS OF PRESSURIZED FLT THE ACFT WOULD HAVE SUFFERED A CATASTROPHIC FAILURE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT SHE WAS CONCERNED ABOUT THIS MATTER BECAUSE OF BEING A CAPT ON THIS SAME TYPE OF EQUIP AND THAT THE COMPANY SHE WORKS FOR MAY NOT FOLLOW THROUGH EFFECTIVELY IN RPTS TO THE FAA AND THE ACFT MANUFACTURER. SHE FURTHER LEARNED THAT THE CAUSE OF THE SUPPORT BEAM FAILURE WAS DUE TO CORROSION. THE ACFT FUSELAGE FRAME MEMBER HAD COMPLETELY CORRODED THROUGH CAUSING FAILURE TO THE OUTSIDE SKIN REPAIR. THE ONLY THING HOLDING THE STRUCTURE TOGETHER WAS THE INSIDE DOUBLER! SHE REITERATED THE NEED FOR A SPECIAL INSPECTION ON THIS TYPE OF ACFT TO DETERMINE IF THERE ARE INDICATIONS OF PROBS, IN PARTICULARLY, THE OLDER PRODUCED ACFT. THIS ACFT WAS APPARENTLY ONE OF THE FIRST FEW BUILT! SHE IS AWARE OF OTHER ACFT HAVING SIMILAR OUTSIDE SKIN REPAIRS.

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.