Safety Recommendation A-82-057

We are pleased to receive the FAA's review and evaluation of the design of all isopropyl alcohol windshield deicing systems on aircraft to verify compliance with Federal Aviation Regulations pertaining to flammable fluid fire protection. We are also pleased to receive a copy of the FAA's of General Aviation Airworthiness Alert No. 64, issued in November 1983, calling attention to the fire hazard resulting from the isopropyl alcohol deicer installation. The actions taken fully comply with Safety Recommendation A-82-57 which is now classified in a "Closed--Acceptable Action" status.

FAA COMMENT: ENCLOSED FOR THE BOARD'S INFORMATION IS A COPY (COVER PAGE AND PAGE 10 ONLY) OF THE NOVEMBER 1983 ISSUE OF THE GENERAL AVIATION AIRWORTHINESS ALERTS, ALERT NO. 64 (ADVISORY CIRCULAR (AC) 43-16). THIS ALERT CALLS ATTENTION TO OUR MUTUAL CONCERN RELATIVE TO ISOPROPYL ALCOHOL DEICE SYSTEMS. AS REQUESTED IN YOUR LETTER DATED JANUARY 18, 1984, ENCLOSED IS A COPY OF THE FEDERAL AVIATION ADMINISTRATION'S (FAA) REVIEW AND EVALUATION OF THE DESIGN OF ALL ISOPROPYL ALCOHOL WINDSHIELD DEICING SYSTEMS ON AIRCRAFT TO VERIFY COMPLIANCE WITH FEDERAL AVIATION REGULATIONS PERTAINING TO FLAMMABLE FLUID FIRE PROTECTION.

THE FAA'S REVIEW AND EVALUATION DID NOT IDENTIFY ANY NONCOMPLIANCE ITEMS NOR WERE THERE ANY UNSAFE CONDITIONS NOT ALREADY CORRECTED BY AIRWORTHINESS DIRECTIVE ACTION.

We are pleased to note that the FAA has completed its review and evaluation of the design of all isopropyl alcohol windshield deice systems on small airplanes to verify compliance with Federal Aviation Regulations. The FAA's action to send a General Notice to alert appropriate facilities to problems in isopropyl alcohol systems and recommending surveillance and reporting of unsafe conditions is an extra step that should greatly reduce the probability of this type of event occurring again. We are pleased also that you will further publicize this problem in the November General Aviation Airworthiness Alerts. The actions taken and ongoing

comply with this recommendation which is now classified in a "Open--Acceptable Action" status. Prior to closing this recommendation, we would appreciate receiving a copy of the FAA's evaluation and details as to the models and number of aircraft affected.

FAA LETTER: THIS REVIEW HAS BEEN COMPLETED AND REVEALED THAT ON OTHER THAN THE MODEL DHC-6 AIRPLANE THERE IS VERY LIMITED ADVERSE SERVICE HISTORY. IN ADDITION, AND ON THE BASIS OF OUR INVESTIGATION, WE BELIEVE THAT ONLY A LIMITED NUMBER OF THE SMALL AIRPLANE POPULATION UTILIZES ISOPROPYL ALCOHOL DEICE SYSTEMS, AND OF THOSE INSTALLATIONS CONFIRMED, AN EVEN SMALLER NUMBER ARE SUSPECTED OF HAVING UNPROTECTED ALCOHOL COMPONENTS WITHIN OCCUPIED COMPARTMENTS. ENCLOSED FOR THE BOARD'S INFORMATION AND FILE IS A COPY OF A GENERAL NOTICE (GENOT) THAT WAS SENT TO ALL APPROPRIATE FAA FACILITIES ALERTING THEM TO THE PROBLEMS WITH ISOPROPYL ALCOHOL SYSTEMS.

THE GENOT RECOMMENDS SURVEILLANCE OF MAINTENANCE MANUALS, PROCEDURES, AND INSPECTION INTERVALS. THE GENOT ALSO REQUESTS THAT ANY UNSAFE CONDITIONS ENCOUNTERED BE REPORTED TO THE SMALL AIRPLANE CERTIFICATION DIRECTORATE FOR EVALUATION AND APPROPRIATE ACTION. THE FAA IS ALSO PUBLISHING A SAFETY ITEM CONCERNING ISOPROPYL ALCOHOL DEICE SYSTEMS IN THE FAA'S GENERAL AVIATION AIRWORTHINESS ALERTS NOVEMBER PUBLICATION.

The project being implemented by the Small Airplane Certification Directorate should, when completed, satisfy the intent of this recommendation. Pending receipt of the results to the Directorate's review and evaluation, Safety Recommendation A- 82-58 will be held in an "Open--Acceptable Action" status.

FAA LETTER: THE FAA'S SMALL AIRPLANE CERTIFICATION DIRECTORATE IN KANSAS CITY ESTABLISHED A PROJECT TO HAVE ALL AIRCRAFT CERTIFICATION OFFICES REVIEW AND EVALUATE THE DESIGN OF ALL ISOPROPYL ALCOHOL WINDSHIELD DEICE SYSTEMS ON SMALL AIRPLANES, THE INSTALLATION OF THESE SYSTEMS IN OCCUPIED COMPARTMENTS, AND SYSTEM COMPLIANCE WITH APPLICABLE FEDERAL AVIATION REGULATIONS. WHEN THIS REVIEW AND EVALUATION IS COMPLETED, WE WILL ADVISE THE BOARD OF OUR CONCLUSIONS AND ANY ACTIONS TAKEN. WE EXPECT OUR REVIEW TO BE COMPLETED BEFORE JULY 1983.

We note that a project is being established to review the design of isopropyl alcohol windshield de-ice systems for compliance with the Federal Aviation Regulations. Pending the results of the FAA's findings, this recommendation is also classified in an "Open--Acceptable Action" status.

FAA LTR: THE FAA'S SMALL AIRCRAFT CERTIFICATION DIRECTORATE IN KANSAS CITY IS ESTABLISHING A PROJECT TO HAVE ALL AIRCRAFT CERTIFICATION OFFICES REVIEW AND EVALUATE THE DESIGN OF ALL ISOPROPYL ALCOHOL WINDSHIELD DEICE SYSTEMS ON SMALL AIRPLANES. THE SURVEY WILL VERIFY COMPLIANCE OF THE DEICING SYSTEMS WITH APPLICABLE FEDERAL AVIATION REGULATIONS.