NTSB · Safety Recommendation
Safety Recommendation A-82-056
Recommendation
THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: ISSUE AN AIRWORTHINESS DIRECTIVE TO REQUIRE A REDESIGN AND MODIFICATION OF ISOPROPYL ALCOHOL WINDSHIELD DEICING SYSTEMS INSTALLED ON DHC-6 AIRCRAFT TO ELIMINATE THE POTENTIAL FOR ALCOHOL LEAKAGE OR, IF PRACTICABLE, TO REQUIRE REPLACEMENT OF THESE SYSTEMS WITH THE ELECTRICALLY HEATED WINDSHIELDS OFFERED BY THE MANUFACTURER AS AN ALTERNATIVE INSTALLATION.
Safety Issue and Context
ON FEBRUARY 21, 1982, A PILGRIM AIRLINES DHC-6-100, N127PM, OPERATING AS FLIGHT 458 BETWEEN GROTON, CONNECTICUT, AND BOSTON, MASSACHUSETTS, WAS FORCED TO MAKE AN EMERGENCY DESCENT FROM CRUISING ALTITUDE BECAUSE OF AN IN-FLIGHT FIRE IN THE COCKPIT AND FORWARD CABIN AREAS. THE AIRCRAFT, WITH 10 PASSENGERS AND 2 CREWMEMBERS ON BOARD, CRASHLANDED ON THE FROZEN SURFACE OF THE SCITUATE RESERVOIR NEAR PROVIDENCE, RHODE ISLAND, THE FIRE CONTINUED TO BURN AFTER THE AIRCRAFT CAME TO REST AND COMPLETELY DESTROYED THE COCKPIT AND PASSENGER CABIN. ONE PASSENGER WAS KILLED AS A RESULT OF THE ACCIDENT.
THE SAFETY BOARD BELIEVES THAT THE ISOPROPYL ALCOHOL WINDSHIELD DEICING INSTALLATION ON THE DHC-6 MODEL AIRCRAFT CONFIGURED FOR OPERATION IN ICING CONDITIONS PRESENTS A FIRE HAZARD WHICH SHOULD BE ELIMINATED. IT IS THE SAFETY BOARD'S UNDERSTANDING THAT DEHAVILLAND AIRCRAFT OFFERS A HEATED WINDSHIELD AS AN ALTERNATE INSTALLATION FOR THOSE AIRCRAFT.
Response History
July 5, 1983 · NTSB Correspondence · FAA
The Safety Board is pleased to note that Airworthiness Directive (AD) 82-26-06 issued on December 27, 1982, eliminated the use of isopropyl alcohol windshield washer/deicing systems on DHC-6 aircraft and required the installation of electrically heated windshields on those DeHavilland DHC-6 airplanes that are certificated for flight into icing conditions. Based on this action, the Safety Board has placed Safety Recommendation A-82-56 in a "Closed--Acceptable Action" status.
April 7, 1983 · Recipient Response · FAA
FAA LETTER: THE FAA ISSUED AIRWORTHINESS (AD) 82-26-06, WAS EFFECTIVE DECEMBER 27, 1982, AND ELIMINATED THE USE OF ISOPROPYL ALCOHOL WINDSHIELD WASHER/DEICING SYSTEMS ON DEHAVILLAND DHC-6 AIRPLANES. THE AD REQUIRES THE INSTALLATION OF ELECTRICALLY HEATED WINDSHIELDS ON THOSE DEHAVILLAND DHC-6 AIRPLANES CERTIFICATED FOR FLIGHT INTO ICING CONDITIONS.
November 2, 1982 · NTSB Correspondence · FAA
We are pleased to be informed that the FAA is developing an Airworthiness Directive (AD) to satisfy this recommendation. Pending the FAA's further response, A-82-56 is classified in an "Open--Acceptable Action" status.
September 28, 1982 · Recipient Response · FAA
FAA LTR: THE FAA IS DEVELOPING AN AIRWORTHINESS DIRECTIVE APPLICABLE TO DHC-6 AIRPLANES EQUIPPED WITH ISOPROPYL ALCOHOL WINDSHIELD DEICE SYSTEMS, WHICH IS IN LINE WITH THE BOARD'S RECOMMENDATION. WE ANTICIPATE THAT THE AD WILL BE ISSUED BEFORE OCTOBER 1982. WE WILL ADVISE THE BOARD WHEN THIS AD IS ISSUED.