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Safety Recommendation Details

Safety Recommendation A-80-113
Details
Synopsis: ON FEBRUARY 12, 1979, AN ALLEGHENY AIRLINES NORD 262 CRASHED ON TAKEOFF FROM CLARKSBURG, WEST VIRGINIA. THE ACCIDENT RESULTED IN TWO FATALITIES AND SEVEN SERIOUS INJURIES. AT THE TIME OF TAKEOFF, THERE WERE LIGHT SNOW SHOWERS AT THE AIRPORT WITH AN ESTIMATED ACCUMULATION RATE OF APPROXIMATELY 1 INCH PER HOUR. DEICING OF THE AIRCRAFT, WITH A 78-PERCENT SOLUTION OF AN ETHYLENE GLYCOL-BASED DEICING FLUID AND WATER, WAS COMPLETED 25 TO 40 MINUTES PRIOR TO TAKEOFF. WITNESSES REPORTEDLY SAW SNOW ON THE EXPOSED HORIZONTAL SURFACES OF THE AIRCAFT WHEN IT TAXIED OUT. THE PROBABLE CAUSE OF THE ACCIDENT WAS DETERMINED TO BE, IN PART, THE LOSS OF LATERAL CONTROL AND LIFT DUE TO SNOW ON THE WINGS AND EMPENNAGE WHEN THE AIRCRAFT CLIMBED OUT OF GROUND EFFECT. THE PRESENCE OF FROZEN SNOW ON THE UPPER HORIZONTAL AIRFOIL SURFACES WAS CONFIRMED BY PHOTOGRAPHS AFTER THE ACCIDENT. ON FEBRUARY 18, 1980, A REDCOAT AIR CARGO, LTD., BRISTOL BRITTANIA 253, CRASHED SHORTLY AFTER TAKEOFF FROM LOGAN INTERNATIONAL AIRPORT, BOSTON. THE ACCIDENT RESULTED IN SEVEN DEATHS AND ONE SERIOUS INJURY. LIGHT SNOW HAD FALLEN THROUGHOUT THE PERIOD OF FLIGHT PREPARATION, TAXI, AND TAKEOFF AT A RATE OF BETWEEN 0.5 AND 0.8 INCH PER HOUR. THE AIRCRAFT HAD BEEN DEICED WITH A 30-PERCENT SOLUTION OF AN ETHYLENE GLYCOL-BASED DEICING FLUID 45 TO 60 MINUTES PRIOR TO TAKEOFF. EVIDENCE INDICATES THAT WET SNOW, WHICH ACCUMULATED ON THE WINGS AND HORIZONTAL STABILIZER PRIOR TO TAKEOFF, WAS A MAJOR FACTOR IN THIS ACCIDENT.
Recommendation: THE NTSB RECOMMENDS THAT THE FEDERAL AVIATION ADMINISTRATION: INITIATE A STUDY OF THE EFFECTIVENESS OF ETHYLENE GLYCOL-BASED DEICING FLUID CONCENTRATIONS AS AN ANTI-ICING AGENT UNDER DIFFERING ICING AND SNOW CONDITIONS.
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: Clarksburg, WV, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA80AA011
Accident Reports: Allegheny Airlines, Inc., Nord 262 Mohawk/Frakes 298, N29824
Report #: AAR-81-03
Accident Date: 2/12/1979
Issue Date: 8/16/1979
Date Closed: 5/10/1983
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Hazmat

Safety Recommendation History
From: NTSB
To: FAA
Date: 5/10/1983
Response: The results of the FAA study of the effectiveness of gylycol-based freeze point depressants as both deicing and anti-icing agents were published in the FAA AC 20- 117. As expressed in our letter of 11/12/82 the Board appreciated the efforts of Data Source: NTSB Recommendations to FAA and FAA Responses the FAA to issue the AC before the winter season. In the letter we also expressed the belief that the FAA should provide positive guidance to operators regarding the deicing/antiicing methods which will provide the best possible results under typical ambient conditions and urged that more conservative assumptions be made with respect to certain data presented in the appendices to the draft advisory circular. We were pleased to note that the appendices have been modified as we suggested and that the text concerning acceptable practices has been expanded to provide further guidance for operational and maintenance personnel finally, we are encouraged by your statement that you will assist in the development of specific industry standards and will publish additional advisory information as necessary. In view of the above, we shall classify Safety Recommendation A-80-113 as closed--acceptable action.

From: FAA
To: NTSB
Date: 3/11/1983
Response: FAA LETTER: AS A RESULT OF FINDINGS DERIVED FROM RESEARCH AND DEVELOPMENT (R&D) EFFORTS CONDUCTED BY THE FEDERAL AVIATION ADMINISTRATION (FAA), ADVISORY CIRCULAR (AC) 20-117, TITLED "HAZARDS FOLLOWING GROUND DEICING AND GROUND OPERATIONS ON CONDITIONS CONDUCIVE TO AIRCRAFT ICING," WAS ISSUED ON DECEMBER 17, 1982. THE PURPOSE OF THIS IS TO EMPHASIZE THE "CLEAN AIRCRAFT CONCEPT" FOLLOWING GROUND DEICING AND GROUND OPERATIONS IN CONDITIONS CONDUCIVE TO AIRCRAFT ICING AND PROVIDE INFORMATION TO ASSIST IN COMPLIANCE. A COPY OF THIS AC WAS DISTRIBUTED TO ALL SEGMENTS OF THE AVIATION COMMUNITY INCLUDING AIRCRAFT OWNERS AND OPERATORS. CONCLUSIONS TO DATE REMAIN THAT SOME FINITE TIME FOR THE LIFE OF THE DEICING FLUID CAN BE ESTIMATED IF SPECIFIC INFORMATION IS AVAILABLE. HOWEVER, BECAUSE OF THE NUMEROUS FACTORS THAT CAN INFLUENCE THESE ESTIMATES AND THE INABILITY OF OPERATORS TO QUANTIFY THESE FACTORS, IT IS NOT PRACTICAL TO USE THAT TECHNIQUE AS A SUBSTANCE FOR PRETAKEOFF INSPECTION. THIS SUBJECT IS DISCUSSED IN DEPTH IN THE AC, AND THE RESULTS OF THE R&D ARE ALSO CONTAINED THEREIN.

From: NTSB
To: FAA
Date: 9/30/1982
Response: We have noted the conclusions from the initial phase of the FAA's study that was initiated during 2/81. More specifically, we understand that deicing fluids in use today should not be considered to have anti-icing qualities during precipitation, that the only way to assure that deicing has been effective is by close inspection of the aircraft just prior to takeoff, and that the best program to determine the effectiveness of deicing fluid as an anti-icing agent was not productive because of the many operational variables. In addition, we have reviewed the second phase of the FAA's study that was approved on 12/23/81. This phase includes a review of U.S. air carrier deicing/inspection procedures, a review of pertinent studies on the effects of icing and frost on aircraft performance and, as required, the development of advisory information. We look forward to receiving the report of this study effort some time in the near future. Safety Recommendation A-80-113 will be classified as open--acceptable action pending receipt of the final report.

From: FAA
To: NTSB
Date: 6/4/1982
Response: FAA LTR: THE FAA HAS CONCLUDED, AS A RESULT OF THE INITIAL PHASE OF THEIR STUDY, THAT: (1) DEICING FLUIDS IN USE TODAY SHOULD NOT BE CONSIDERED TO HAVE ANTI-ICING QUALITIES DURING PRECIPITATION; (2) THE ONLY WAY TO ASSURE DEICING HAS BEEN EFFECTIVE AND THAT THE AIRCRAFT IS CLEAN OF ICE/SNOW/FROST IS BY CLOSE INSPECTION JUST PRIOR TO TAKEOFF; AND (3) THE TEST PROGRAM TO DETERMINE THE EFFECTIVENESS OF DEICING FLUID STRICTLY AS AN ANTI-ICING AGENT WAS NOT PRODUCTIVE BECAUSE OF THE MANY OPERATIONAL VARIABLES. THE FAA STARTED WORK ON THE SECOND PHASE OF THIS STUDY ON DECEMBER 23, 1981. THIS PHASE INCLUDES A REVIEW OF U.S. AIR CARRIER DEICING/INSPEC TION PROCEDURES, A REVIEW OF PERTINENT STUDIES ON THE EFFECTS OF ICE AND FROST ON AIRCRAFT PERFORMANCE, AND THE DEVELOPMENT OF ADVISORY INFORMATION AS REQUIRED. THE FAA ALSO PLANS TO CONDUCT LIMITED TESTING AND R&D WORK TO VERIFY THE ESTIMATE OF ICE/SNOW FORMATIONS UNDER DIFFERENT ATMOSPHERIC CONDITIONS TOGETHER WITH DIFFERENT DEICING MIXTURES; AND, TO VERIFY THE TECHNIQUES FOR ESTIMATED FLUID FILM THICKNESS AS A FUNCTION OF SELECTED VARIABLES. THE FAA WILL PREPARE A REPORT CONTAINING THE RESULTS OF THESE EFFORTS SOMETIME IN OCTOBER 1982.

From: NTSB
To: FAA
Date: 3/22/1982
Response: In Safety Recommendation A-80-113 we asked the FAA to initiate a study of the effectiveness of ethylene glycol-based deicing fluid concentrations as an anti- icing agent under differing icing and snow conditions. The FAA's response indicated that a study on ethylene glycol-water deicing mix as an anti-icing agent under differing icing and snow accumulation from taxi to takeoff. We were told that the FAA intended to initiate a study through its R&D organization and that the Safety Board would be kept informed of the results of the study. We would now very much appreciate receiving a progress report of the study. Safety Recommendation A-80-113 continues to be maintained in an open--acceptable action status.

From: NTSB
To: FAA
Date: 3/30/1981
Response: We note that the FAA intends to initiate a study and inform the Safety Board of its findings. This recommendation is classified in an open--acceptable action status.

From: FAA
To: NTSB
Date: 2/11/1981
Response: FEDERAL AVIATION ADMINISTRATION LTR: DURING THE APRIL 1969 FAA AIRCRAFT ICE PROTECTION SYMPOSIUM, IT WAS EMPHASIZED THAT PRIOR TO FLIGHT, THE FINAL INSPECTION MUST ASSURE A CLEAN-SURFACED WING. THIS REQUIREMENT REMAINS VALID REGARDLESS OF THE EFFECTIVENESS OF EITHER FLUID USED; DEICING OR ANTI-ICING. THE FAA BELIEVES THESE CRITERIA ARE ADEQUATE FOR RELEASE TO TAXI. WE ALSO BELIEVE, HOWEVER, THAT A STUDY ON ETHYLENE-GLYCOL-WATER DEICING MIX AS ANTI ICING AGENT UNDER DIFFERING ICING AND SNOW CONDITIONS WILL PROVIDE SIGNIFICANT INFORMATION ON WING SURFACE SNOW ACCUMULATION FROM TAXI TO TAKEOFF. ACCORDINGLY, WE INTEND TO INITIATE A STUDY THROUGH OUR R & D ORGANIZATION AND THE BOARD WILL BE INFORMED OF THE RESULTS OF THIS STUDY.