ROCHESTER, IN, USA
N210SU
BEECH BE200
THE PILOTS REPORTED THEY WERE IN CRUISE FLIGHT AT 16,000 FEET, WHEN THEY HEARD A LOUD NOISE, FOLLOWED BY 'MASTER WARNING' AND 'CABIN ALTITUDE' LIGHTS, AND A LOSS OF CABIN PRESSURIZATION. THEY STATED WHEN THEY LOOKED BACK TO THE REAR CABIN THEY SAW THE RIGHT REAR CABIN WINDOW HAD FAILED. THE PILOTS DIVERTED AND LANDED WITHOUT FURTHER INCIDENT. POSTINCIDENT INVESTIGATION REVEALED THE FAILED WIND0W WAS INSTALLED IN OCTOBER, 1985. THE AIRPLANE HAD FLOWN APPROXIMATELY 2100 HOURS AND BEEN REPAINTED TWICE SINCE THAT DATE. THE AIRPLANE HAD FLOWN 4.8 HOURS SINCE THE MOST RECENT REPAINTING. THE MANUFACTURER'S MANUALS AND SERVICE INSTRUCTIONS CAUTIONED THAT EXPOSURE TO PAINT, PAINT STRIPPER, SOLVENTS AND FUMES COULD RESULT IN CRACKED WINDOWS. THEY RECOMMENDED THE USE OF PRESSURE SENSITIVE MASKS, AND STATED, '...THE MASK MUST EXTEND BEYOND THE WINDOW CUTOUTS...[TO] PREVENT THE CHEMICAL COMPOUNDS FROM ATTACKING THE WINDOW EDGES.' EXAMINATION OF THE AIRPLANE'S WINDOWS REVEALED EVIDENCE OF STRIPPER AND PAINT OVERSPRAY.
HISTORY OF FLIGHT On March 16, 1994, about 0827 eastern standard time, a Beech BE200, N210SU, registered to Ohio State University, and operated on the business flight by B. F. Goodrich Avionics Division, experienced a loss of pressurization when a cabin window blew out during cruise flight at 16,000 feet over Rochester, Indiana. The airplane diverted and landed without further incident at Ft. Wayne, Indiana. The airplane sustained minor damage. The pilot, co-pilot and three passengers reported no injuries. Visual meteorological conditions prevailed for the flight, an IFR flight plan was filed. The flight operated under 14 CFR Part 91, and originated from Columbus, Ohio, exact time unknown. The intended destination was Spencer, Iowa. The pilots stated the airplane was in cruise flight at 16,000 feet Mean Sea Level (MSL) when they heard a loud noise from the rear of the airplane, and the MASTER WARNING and CABIN ALTITUDE lights illuminated. The pilots reported when they glanced back to the cabin they observed a window in the right rear of the airplane was broken. Several coats and a gym bag were lost through the window during the subsequent loss of cabin pressurization. The flight crew advised Air Traffic Control (ATC) they had experienced a loss of cabin pressurization, and requested the nearest airport. After some discussion, the pilots elected to divert to Fort Wayne, Indiana, where they landed without further incident. Excerpts from the ATC package are appended. Postincident investigation revealed the teardrop shaped baggage window located on the right side of the aft cabin area was broken, and most of the window pieces were missing. Examination of the window frame, the remaining window fragments, and the other airplane windows revealed evidence of paint stripper and paint overspray. The Director of Maintenance for the operator stated the overspray was noted and discussed during the acceptance inspection after a recent repainting. He reported paint shop personnel reassured him "This is how we've done it for 20 years." The operator accepted the airplane back into service. The damaged window frame and remaining window fragments were removed and transported to National Transportation Safety Board (NTSB) Materials Laboratory in Washington, D.C. The Metallurgist's Factual Report stated "...Wallner lines were visible on the walls of the radial crack through the glass, and the orientation of the lines indicated that the crack initiated at the outer surface of the window and propagated towards the window frame...inspection disclosed that the primary initiation of the circumferential fracture was at the intersection of the radial crack with the inside surface of the window...appeared to be white paint on the periphery of the outer surface of the window... ." The Factual Report is appended. AIRCRAFT INFORMATION Examination of the airplane maintenance records indicate the airplane had 4,378.7 hours total flight time, and 5,003 cycles at the time of the incident. Company maintenance personnel report the airplane underwent an Airworthiness Inspection dated March 12, 1994, at an airplane total time of 4,375.7 hours. The Director of Maintenance reported all applicable Service Bulletins (SBs) and Airworthiness Directives (ADs) were addressed at the time of the inspection. The right rear baggage window (P/N 101-440042-2) was installed in the airplane October 1, 1985, at an airplane total time of 2,276.1 hours. The airplane had flown approximately 2,100 hours, and been repainted twice since that installation. The airplane was first repainted May 16, 1986 at an estimated airplane total time of 2,410 hours. The most recent repainting occurred March 4, 1994, at an airplane total time of 4,373.9 hours, approximately 4.8 flight hours (and 3 cycles) before this incident occurred. Mmaintenance records are appended. The Director of Maintenance reported most of the 4.8 hours flown after the airplane was received from the paint shop was low altitude (below 10,000 feet) operation for positioning, avionics/equipment testing, and other maintenance purposes. He stated the incident flight was the first time the airplane reached maximum cabin differential pressure since it was repainted. ADDITIONAL INFORMATION The Beech BE200 Maintenance Manual contains a section on general maintenance practices for windows. This section addresses "Precautions required when stripping, painting or degreasing." The Manual states: "Paint, paint strippers, degreasing compounds, and most solvents will seriously damage acrylic windows. If any of these functions are to be performed in the vicinity of the windows, the windows must be completely sealed against the chemical compounds and fumes. Pressure sensitive polyester film...and pressure sensitive painting/stripping masks of polyester, aluminum and other composite materials are commercially available for this purpose. When installed, the mask must extend beyond the window cutouts...[to] prevent the chemical compounds from attacking the window edges." Excerpts from the maintenance manual are appended. Beech Aircraft Corporation has issued several documents pertinent to the windows installed in the BE200 airplane. Specifically, Mandatory Service Bulletin Number 2208, issued in October, 1987, addressed the "Inspection, maintenance, protection and/or replacement of cabin, storm and baggage side windows." The SB cautions: "Acrylic windows are extremely susceptible to damage during painting, stripping and fuselage cleaning operations. Improper protection of the acrylic windows can cause severe chemical damage which will result in reduced service life and structural failure of the acrylic." Records indicate the operator complied with SB Number 2208 on a recurring basis every 100 hours of operation. The SB was most recently accomplished March 12, 1994, at an airplane total time of 4,375.7 hours. A copy of the SB is appended.
the airplane painter/refinishers' failure to follow appropriate procedures/directives pertinent to the masking, stripping, painting and cleaning of the airplane cabin windows, which resulted in the in-flight failure of the right aft cabin window. A related factor is inadequate maintenance inspection by company maintenance personnel.
Source: NTSB Aviation Accident Database
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