You may be trying to access this site from a secured browser on the server. Please enable scripts and reload this page.
Turn on more accessible mode
Turn off more accessible mode
Skip Ribbon Commands
Skip to main content
Top Link Bar
NEWS & EVENTS
Speeches & Testimony
Most Wanted List
The Investigative Process
Data & Stats
General Aviation Safety
Assistance to Families & Victims
Operations & Policy
Administrative Law Judges
Strategic Plans & Reports
Safety Recommendation Details
The Investigative Process
Data & Stats
General Aviation Safety
INFOMATION FROM THE CVR INDICATES THAT THE FLIGHTCREW ACTIVATED THE ANTI-ICE EQUIPMENT FOR THE WINDSHIELD, PROPELLERS, PITOT PROBES, ANGLE-OF ATTACK VANES, SIDESLIP ANGLE VANE, & TOTAL AIR TEMPERATURE PROBES. THERE IS NO EVIDENCE FROM THE CVR, FDR, PERFORMANCE OF THE AIRCRAFT, OR AIRCRAFT WRECKAGE TO DETERMINE IF THE FLIGHTCREW ACTIVATED THE DE-ICING BOOTS. THESE FACTS & THE AIRPLANE'S DEGRADED AERODYNAMIC PERFORMANCE STRONGLY SUGGEST THAT ICE HAD ACCUMULATED ON AIRFRAME, BUT MAY NOT HAVE SEEN OR RECOGNIZED AS A HAZARD BY THE FLIGHT CREW OF COMAIR 3272. THERE WERE SEVEN ACCIDENTS INVOLVING AIRCRAFT EMBRAER EMB- 120: (1) 1/9/97, EMBRAER EMB-120, MONROE, MICHIGAN, (2) IN APRIL OF 1995, EMBRAER EMB -120, TALLAHASSEE, FLORIDA, (3) 10/16/94, EMBRAER EMB-120, ELKO, NEVADA, (4) 4/29/93, EMBRAER EMB -120, PINE BLUFF, ARKANSAS, (5) 11/22/91, EMBRAER EMB -120, CLERMONT-FERRAND, FRANCE, (6) IN SEPTEMBER, 1991, EMBRAER EMB -120, FORT SMITH, ARKANSAS,& (7) 6/28/89, EMBRAER EMB- 120, KLAMATH FALLS, OREGON.
THE NTSB RECOMMENDS THAT THE FAA: REQUIRE THAT ALL EMB-120 AIRCRAFT BE EQUIPPED WITH AUTOMATED ICE DETECTION & CREW ALERTING SYSTEMS FOR DETECTING AIRFRAME ICE ACCRETION. (URGENT)
Original recommendation transmittal letter:
Closed - Acceptable Action
MONROE, MI, United States
In-Flight Icing Encounter and Uncontrolled Collision with Terrain, Comair Flight 3272, Embraer EMB-120RT, N265CA
Addressee(s) and Addressee Status:
FAA (Closed - Acceptable Action)
Safety Recommendation History
A-97-34, WHICH ASKED THE FAA TO REQUIRE THAT ALL EMBRAER MODEL EMB-120 AIRCRAFT BE EQUIPPED WITH AUTOMATED ICE DETECTION & CREW ALERTING SYSTEMS FOR DETECTING AIRFRAME ICE ACCRETION. BASED ON THIS ACTION, THE BOARD CLASSIFIES A-97-34 "CLOSED--ACCEPTABLE ACTION."
ON 12/11/97, THE FAA ISSUED AIRWORTHINESS DIRECTIVE (AD) 97-26-06 APPLICABLE TO ALL EMBRAER -EMB-120 SERIES AIRPLANES. THE AD MANDATES A REVISION TO THE AIRPLANE FLIGHT MANUAL (AFM) TO INCLUDE REQUIREMENTS FOR ACTIVATION OF THE ICE PROTECTION SYSTEMS & TO ADD INFO REGARDING OPERATION IN ICING CONDITIONS. THE AD ALSO REQUIRES THE INSTALLATION OF AN ICE DETECTOR SYSTEM & A REVISION TO THE AFM TO INCLUDE PROCEDURES TO TEST THE INTEGRITY OF THE SYSTEM.
THE BOARD STRONGLY SUPPORTS THE REQUIREMENTS OR AIR CARRIERS TO INSTALL AN ICE DETECTION/ALERTING SYSTEM & TO REVISE THE "LIMITATIONS" SECTION OF THE EMB-120 AFM TO REQUIRE FLIGHTCREWS TO IMMEDIATELY ACTIVATE THE DE-ICING EQUIPMENT WHEN THEY OR THE SYSTEM DETECT ICE. THEREFORE, THE BOARD CLASSIFIES A-97-34 "OPEN--ACCEPTABLE RESPONSE." THE COMMENT PERIOD FOR THE NPRM HAS EXPIRED, & THE BOARD WOULD APPRECIATE BEING ADVISED OF THE FAA'S ANTICIPATED TIMEFRAME FOR COMPLETION OF THIS IMPORTANT RULEMAKING PROJECT, & THE SCHEDULE FOR DESIGNING & INSTALLING THE REQUIRED SYSTEMS. ANOTHER ICING SEASON IS FAST APPROACHING, & THE BOARD REQUESTS THAT THE FAA RESPOND TO THIS LETTER WITH DETAILS ON HOW IT PLANS TO ADDRESS EACH ONE OF THE BOARD'S URGENT RECOMMENDATIONS.
Notation 6869: The National Transportation Safety Board has reviewed the subject Notice of Proposed Rulemaking (NPRM) published in the Federal Register, Volume 62, Number 92, Pages 26258- 26261. The proposed Airworthiness Directive (AD) would require installing an ice detection system and revising the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) of Embraer 120 (EMB-120) airplanes to include requirements for activation of the ice protection and de-icing systems. The AD would also require revising the Normal Procedures Section of the FAA approved AFM to establish a minimum speed of 160 knots in icing conditions (or adding 10 knots to the approved speeds for various flap deflections during approach to landing). The NPRM resulted from events in which flightcrews did not activate the de-icing boots before having difficulties controlling the airplane either during or following flight in icing conditions. The flight crews in these events either were not aware of ice accretion, or did not believe that ice accretion was severe enough to activate the de-ice boots. As a result of these events, including the Comair EMB-120 accident in Monroe, Michigan, on January 9, 1997, (which is still under investigation) the Safety Board issued four urgent safety recommendations to the FAA on May 21, 1997, as follows: • Require air carriers to reflect FAA-approved minimum airspeeds for all flap settings and phases of flight, including flight in icing conditions, in their EMB-120 operating manuals. (Urgent) (A-97-3l) • Ensure that the de-icing information and procedures in air carriers' EMB-120 operating manuals and training programs are consistent with the revised Embraer EMB-120 airplane flight manual. (Urgent) (A-97-32) • Direct Principal Operations Inspectors (POls) to ensure that all EMB-120 operators provide flight crews with training that emphasizes the recognition of icing conditions and the need to adhere to the procedure for using de-ice boots that is specified in the revised Embraer EMB-120 airplane flight manual. (Urgent) (A-97-33) • Require that all EMB-120 aircraft be equipped with automated ice detection and crew alerting systems for detecting airframe ice accretion. (Urgent) (A-97-34) According to the NPRM, the actions specified in the proposed AD are intended to ensure that the flight crew is able to recognize the formation of significant ice accretion and take appropriate action. The Board is concerned about use of the word "significant" in the NPRM to describe ice accretion. Although in the events that led to the NPRM the degradation in airplane performance was indeed significant, the amount of ice accretion was most likely perceived by the flight crews involved as small (and not likely "significant"). Thus, the Safety Board believes that the proposed AD requirement to turn on wing and tail de-icing equipment "at the first sign of ice formation anywhere on the aircraft" is very appropriate. The provisions of the FAA's proposed AD parallel our recommendations in many respects, and the Safety Board strongly supports it. However, the proposed AD does not address several issues. The Safety Board believes that setting a clear 160-knot minimum speed in icing conditions will provide an immediate improvement in safety and should be implemented. Further icing tests planned by the FAA and Embraer may show that a higher minimum airspeed is required to provide an adequate safety margin. However, it is not clear if the language provided in the proposed AD establishes appropriate speeds for all conditions. Safety Recommendation A-97-31 asks for " ... FAA-approved minimum airspeeds for all flap settings and phases of flight, including flight in icing conditions...." The Board believes this needs to be addressed more specifically in the final rule, or in subsequent action after all planned EMB-120 testing is complete. Further, the NPRM does not specify how the 160-knot recommended minimum icing airspeed and other changes in the Normal Procedures Section of the FAA-approved AFM will be implemented in operator flight manuals and training programs. The Board's concern stems from the fact that although Embraer issued revision number 43 to the Normal Procedures Section of its AFM to require activating the de-ice boots "at the first sign of ice formation" (revision number 43 was approved by the FAA), this new icing procedure was not implemented by Comair. The Board continues to believe, as it stated in Safety Recommendation A-97-32, that all of the de-icing information and procedures in EMB-120 operating manuals and training programs of air carriers should be consistent with the revised Embraer EMB-120 AFM. The Board is concerned that pilots have been trained for years to operate the de-ice boots only after 114 to Y2 inch of ice has accumulated on the wings. 1 The proposed AD does not address the issue of flight crew training for flight in icing conditions, and the Safety Board believes that the pilots need to be provided training to unlearn old habits and to emphasize the new icing procedures. Therefore, the Board urges the FAA to consider the incorporation ofEMB-120 flight crew training into the proposed rule, as outlined in Safety Recommendation A-97-33. The Safety Board strongly supports the NPRM requirement to install an ice detector on all EMB-120 aircraft, and to require flight crews to activate the de-icing equipment immediately when ice is detected either by the system or the flight crew. The Safety Board appreciates the opportunity to comment on this rulemaking proposal.
THE FAA PUBLISHED A NOTICE OF PROPOSED RULEMAKING (NPRM) 97-NM-46-AD ON 5/13/97, TO ADDRESS EMB-120 ICING ISSUES. THE NPRM PROPOSES SEVERAL ACTIONS CONCERNING EMB-120 ICING: (1) REQUIRE INSTALLING AN ICE DETECTION SYSTEM; (2) REVISE THE "LIMITATIONS" SECTION OF THE FAA-APPROVED EMB-120 AIRPLANE FLIGHT MANUAL (AFM) TO INCLUDE REQUIREMENTS FOR ACTIVATION OF THE ICE PROTECTION & DE-ICING SYSTEMS; & (3) REQUIRE REVISION OF THE "NORMAL PROCEDURES" SECTION OF THE AFM TO ESTABLISH A MINIMUM SPEED OF 160 KNOTS IN ICING CONDITIONS (EXCEPT DURING APPROACH TO LANDING, WHEN IT REQUIRES ADDING 10 KNOTS TO THE APPROVED SPEEDS FOR EACH FLAP POSITION).
Strategic Plan, Performance & Accountability Reports & More
Directions to Conference Center
Web Policies & Notices
Annual Review of Aircraft