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Safety Recommendation Details

Safety Recommendation A-98-101
Details
Synopsis: On January 9, 1997, an Empresa Brasileira de Aeronautica, S/A (Embraer) EMB-120RT, operated by COMAIR Airlines, Inc., crashed during a rapid descent after an uncommanded roll excursion near Monroe, Michigan. The flight was a scheduled, domestic passenger flight from the Cincinnati/Northern Kentucky International Airport, Covington, Kentucky, to Detroit Metropolitan/Wayne County Airport, Detroit, Michigan. The flight departed Covington with 2 flightcrew, 1 flight attendant, and 26 passengers on board. There were no survivors. The airplane was destroyed by ground impact forces and a postaccident fire. IMC prevailed at the time of the accident, and the flight was operating on an IFR flight plan.The probable cause of this accident was the FAA's failure to establish adequate aircraft certification standardds for flight in icing conditions.
Recommendation: TO THE FEDERAL AVIATION ADMINISTRATION: Review turbopropeller-driven airplane manufacturers' airplane flight manuals and air carrier flightcrew operating manuals (where applicable) to ensure that these manuals provide operational procedures for flight in icing conditions, including the activation of leading edge deicing boots, the use of increased airspeeds, and disengagement of autopilot systems before entering icing conditions (that is, when other anti-icing systems have traditionally been activated).
Original recommendation transmittal letter: PDF
Overall Status: Closed - Acceptable Action
Mode: Aviation
Location: MONROE, MI, United States
Is Reiterated: No
Is Hazmat: No
Is NPRM: No
Accident #: DCA97MA017
Accident Reports: In-Flight Icing Encounter and Uncontrolled Collision with Terrain, Comair Flight 3272, Embraer EMB-120RT, N265CA
Report #: AAR-98-04
Accident Date: 1/9/1997
Issue Date: 11/30/1998
Date Closed: 5/10/2006
Addressee(s) and Addressee Status: FAA (Closed - Acceptable Action)
Keyword(s): Icing, Weather

Safety Recommendation History
From: NTSB
To: FAA
Date: 2/28/2007
Response: Notation 7677B: The National Transportation Safety Board has reviewed the Federal Aviation (FAA) Notice of Proposed Rulemaking (NPRM), Airworthiness Directives; The Cessna Aircraft Company Models 208 and 208B Airplanes, which was published at 72 Federal Register 4663 on February 1, 2007. The NPRM proposes to supersede Airworthiness Directive (AD) 2006-06-06, which applies to Cessna Aircraft Models 208 and 208B. On January 17, 2006, as a result of the preliminary findings from two foreign investigations of fatal accidents involving Cessna 208 series airplanes in icing conditions, and a previous assessment of Cessna 208 icing incidents and accidents, the Safety Board issued the following safety recommendations to the FAA: Require all operators of Cessna 208 series airplanes to maintain a minimum operating airspeed of 120 knots during flight in icing conditions, even if a descent is required to do so. (A-06-01) (Urgent) Prohibit all operators of Cessna 208 series airplanes from conducting flight into any icing conditions determined to be more than light icing. (A-06-02) (Urgent) Require all operators of Cessna 208 series airplanes to disengage the autopilot and fly the airplane manually when operating in icing conditions. (A-06-03) (Urgent) On March 16, 2006, the FAA adopted Airworthiness Directive (AD) 2006-06-06. The AD affects all Cessna 208 and 208B aircraft, and requires incorporation of changes to the Airplane Flight Manual (AFM) for these aircraft as well as placement of placards in the cockpit providing information about operations under icing conditions. The changes to the AFM (1) require a minimum airspeed of 120 knots indicated air speed (KIAS) when the flaps are up for all phases of flight in icing conditions, (2) prohibit operation of the aircraft in icing conditions that are moderate or greater, and (3) require disengagement of the autopilot if icing conditions are encountered. The AD defines “moderate icing conditions” for the Cessna 208 series of aircraft specifically as any one of the following conditions: • Airspeed in level flight at constant power decreases by 20 KIAS. • Engine torque required to maintain airspeed increases by 400 ft. lbs. • 120 KIAS cannot be maintained in level flight. • Ice accretion of ¼ inch observed on the wing strut. On November 15, 2006, the Safety Board noted that the issuance of AD-2006-06-06 fully met the intent of Safety Recommendations A-06-1, -2, and –3, and classified these Recommendations “Closed – Acceptable Action.” In commenting on the NPRM that would supersede AD-2006-06-06, the Safety Board seeks to ensure that the safety improvements obtained through that AD are not diminished. The Safety Board is satisfied that the intent of Safety Recommendations A-06-01 and A-06-02 are retained in the new NPRM, but is concerned that the new “Low-Speed Awareness System” proposed in the NPRM, which will supersede the requirement to disconnect the autopilot in icing conditions, may not provide a level of safety equivalent to disconnecting the autopilot in icing conditions, as recommended in A-06-03 and as required in AD-2006-06-06. The Intent of A-06-01 and A-06-02 as Addressed in the NPRM Although the NPRM no longer uses the term “moderate icing conditions” to identify icing conditions in which continued flight is prohibited, it does retain specific and quantitative performance-based measures for determining when to exit icing conditions. In addition, the changes to the AFM proposed in the NPRM would oblige pilots to immediately act to exit icing conditions if any of a number of qualitative criteria describing the icing environment are met. Specifically, the proposed changes to the AFM would require pilots to take immediate actions to exit icing conditions under the following conditions: 1. Unusually extensive ice accretions on the airframe in areas that do not normally collect ice. 2. Accumulation of ice on the upper or lower surface of the wing aft of the protected area. 3. Heavy ice accumulations on the windshield, or ice accumulations aft of the curved sections on the windshield. 4. Ice accumulations aft of the protected surfaces of the wing struts. 5. Visible rain or drizzle at temperatures below +5º C outside air temperature. 6. Droplets that splash or splatter on impact at temperatures below +5º C outside air temperature. The NPRM proposes the following additional quantitative performance-based measures for determining when to exit icing conditions: 1. Airspeed of 120 KIAS cannot be maintained in level flight. 2. Airspeed decrease of 10 KIAS that cannot be prevented by increase to max continuous power. 3. Minimum en route IFR altitude (MEA) or minimum obstruction clearance altitude (MOCA) (if applicable) on current leg falls into area “C” of the icing service ceiling chart contained in Section 5 of the Known Icing AFM Supplement. The Safety Board believes that these changes to the AFM retain the intent and equivalent level of safety envisioned in Safety Recommendations A-06-01 and A-06-02 and mandated in AD-2006-06-06, and so has no objection to their inclusion in the final rule. The Intent of A-06-03 as Addressed in the NPRM In the letter transmitting Safety Recommendation A-06-03 to the FAA, the Safety Board stated the following: It is difficult for pilots to effectively monitor control inputs made by an autopilot and detect changes in the magnitude and direction of these inputs as an airplane’s performance degrades due to icing conditions … The Safety Board concludes that manually flying the Cessna 208 in icing conditions is necessary to enable pilots to sense the aerodynamic effects of icing and enhance their ability to retain control of the airplane. The Safety Board has made similar observations in the course of other accident investigations, and previously recommended that crews of other aircraft types be required to disconnect the autopilot in icing conditions. For example, recommendation A-94-184, issued as a result of the investigation of an accident involving an ATR-72-210 aircraft, recommended that the FAA prohibit the use of the autopilot on ATR-42 and ATR-72 aircraft in icing conditions. Recommendation A-98-97, issued as a result of the investigation involving an Embraer EMB-120RT aircraft, recommended that the FAA require all operators of turbopropeller-driven air carrier airplanes to require pilots to disengage the autopilot and fly their airplanes manually when they activate the anti-ice systems. Recommendation A-98-101, also issued as a result of the EMB-120RT accident investigation, recommended the following to the FAA: Review turbopropeller-driven airplane manufacturers’ airplane flight manuals and air carrier flightcrew operating manuals (where applicable) to ensure that these manuals provide operational procedures for flight in icing conditions, including the activation of leading edge deicing boots, the use of increased airspeeds, and disengagement of autopilot systems before entering icing conditions (that is, when other anti-icing systems have traditionally been activated). Recommendation A-06-51, issued as a result of the investigation of an accident involving a Saab-Scania AB SF340B+ aircraft, recommended that the FAA require all operators of turbopropeller-driven airplanes to instruct pilots, except during intermittent periods of high workload, to disengage the autopilot and fly their airplanes manually when operating in icing conditions. As these recommendations indicate, the Safety Board has consistently determined in its investigations of icing-related accidents that safety is enhanced when pilots are part of the control-loop while operating in icing conditions. The changes in aircraft handling qualities that can accompany ice accretion are indicators that airplane performance is being degraded and that corrective action is required. However, pilots are more likely to be aware of these indicators if they are in direct control of the aircraft. AD-2006-06-06 currently requires pilots of Cessna 208 series airplanes to disconnect the autopilot “at first indication of ice accretion.” This requirement fully met the intent of Safety Recommendation A-06-03, and so, in November 2006, the Safety Board classified A-06-03 “Closed – Acceptable Action.” However, AD-2006-06-06 also states the following: Although we have not previously proposed limitations on autopilot use in icing, the limitation on autopilot use is an interim action until an acceptable low speed annunciation system is developed and installed on the airplane. The Safety Board notes that although the NPRM retains the requirement to disconnect the autopilot at first indication of ice accretion for airplanes that do not have the “Low Air Speed Awareness System (SK208-171),” it also states that the autopilot need not be disconnected at first indication of ice accretion on airplanes that do have the system. Because the NPRM would require the eventual installation of the system on all Cessna 208 series aircraft, pilots would then not have to disconnect the autopilot. Since closing Safety Recommendation A 06-03, the Safety Board has re-evaluated its position regarding the Low Air Speed Awareness System and is concerned that it may not provide the same level of icing awareness as called for by A-06-03 and mandated in AD 2006-06-03 (that is, for pilots to disconnect the autopilot and fly their airplanes manually in icing conditions). Further, Recommendation A-06-51, issued as a result of the investigation of the Saab-Scania accident, reiterates the Safety Board’s concerns about not using the autopilot when in icing conditions. Revision 9 to “Supplement S1 — Known Icing Equipment” to the AFM, contains the following guidance under Low Air Speed Awareness System: An advisory annunciator is installed just above the annunciator panel … and is labeled BELOW ICING MIN SPD. This annunciator illuminates when the propeller anti-ice switch is in the ON position and the indicated airspeed is less than 108 ± 2 kts. This annunciator will illuminate with a white background color. After initially obtaining 108 ± 2 kts after takeoff, any subsequent airspeed decrease below this value will cause the annunciator to illuminate with an amber background color and flash. An aural horn will also sound to alert the pilot to the need to take appropriate action to increase airspeed. For approaches with flaps at 10º or 20º the horn may be cancelled by pushing the switch light. The horn aural will cease and the light will illuminate white color and be steady ON. The Safety Board notes that the low air speed alert provided by this system will not activate until the airplane is well below the minimum flaps-up airspeed for flight in icing conditions (120 KIAS), and approximately 2 knots below the minimum speed to be used when climbing to exit icing conditions. Operated in this fashion, the low speed alert in effect acts as a stall-warning system for icing conditions. Consequently, the NPRM would allow the autopilot to remain engaged while the airspeed degrades due to ice accretion to below the minimum safe airspeed. During such performance degradation, the pilot would not have direct control of the airplane. Accordingly, he or she would not be able to sense the aerodynamic effects of the ice accretion and would therefore be at increased risk of losing control of the airplane. This situation is exactly that addressed by Safety Recommendation A-06-03, and that which AD-2006-06-06 addressed satisfactorily by requiring pilots to disconnect the autopilot at first indication of ice accretion. Revision 9 to “Supplement S1 -- Known Icing Equipment” to the AFM also contains the following guidance: The autopilot may be used in icing conditions if not prohibited (see limitations section). However, every 10-15 minutes the autopilot should be disconnected to detect any out of trim conditions caused by ice buildup. If significant out of trim conditions are detected, the autopilot should remain off for the remainder of the icing encounter so that the pilot may monitor for additional force buildup. This guidance only partially addresses the intent of Safety Recommendation A-06-03. The guidance is not mandatory (it is contained in the “Normal Procedures” section of the AFM Supplement, and not in the “Limitations” section), and permits “significant out of trim conditions” to appear as a result of ice accretion before the pilot needs to fly manually to “monitor for additional force buildup.” This procedure introduces a delay in the pilot’s recognition of the airplane’s handling degradation as a result of ice buildup and shortens the amount of time available to exit icing conditions before the ice accretion becomes critical. By flying the airplane manually at the first sign of ice accretion, as required by AD-2006-06-06, the pilot continuously monitors the airplane’s handling qualities and can detect degradation when it first appears. Furthermore, flying the airplane manually increases the likelihood that pilots will detect any degradation in airplane performance (such as a decay in airspeed or an increase in the power required to maintain airspeed) at the earliest opportunity. For these reasons, the Safety Board believes that the Low Air Speed Awareness System does not address the intent of A-06-03 and does not provide the same level of safety as the autopilot disconnect requirement in AD 2006-06-06. Furthermore, the system as designed does not provide an alert until the airspeed has decayed to at least 10 knots below the minimum safe airspeed in icing conditions, at which point the airplane performance may already be degraded due to ice accumulation, such that a flaps-up climb at 110 KIAS to escape the icing conditions (as permitted by the AFM) may not be possible. Therefore, the Safety Board believes that installation of the low speed awareness system should not provide relief from the requirement to disconnect the autopilot at first indication of ice accretion. NPRM Requirements Not Related to Safety Recommendations A-06-01 through A 06-03 The NPRM also requires the following in regard to pilot training: The pilot-in-command must successfully complete specific training for flight into icing conditions provided by Cessna Aircraft Company within the 12 calendar months preceding any flight into known or forecast icing conditions. Safety is enhanced when pilots are aware of the serious risks associated with aircraft icing of all types – both ground icing, and in-flight ice accretion – and when they have the knowledge and skills to manage those risks effectively. The training requirement contained in the NPRM is promising in this regard, and together with the airplane limitations intended by Safety Recommendations A-06-01 through A-06-03 and required in AD-2006-06-06, should improve the safety of cold-weather operations with Cessna 208 series airplanes. The Safety Board therefore agrees with the pilot training requirement proposed in the NPRM. The Safety Board appreciates the opportunity to comment on this NPRM.

From: NTSB
To: FAA
Date: 5/10/2006
Response: The Safety Board reviewed the FAA's response to Safety Recommendation A-98-94, which the FAA provided to the Board in August 2004 following a Safety With A Team (SWAT) meeting. That response detailed the FAA's review of information available to pilots in the airplane flight manuals and flightcrew operating manuals. Based on that information, the FAA has reviewed these manuals, as recommended, to ensure that they provide operational procedures for flight in icing conditions. In addition, on February 17, 2000, the FAA issued Joint Flight Standards Information Bulletin for Air Transportation 00-02 and General Aviation 00-01, "Use of Autopilot During In-Flight Icing Conditions for Turbopropeller-Driven Airplanes," which directs the FAA's principal operations inspectors to ensure that an airline's approved operating procedures include guidance on the use of the autopilot in icing conditions and procedures to check for unusual trim forces and aircraft response. With the completion of the review of the manuals performed in response to Safety Recommendation A-98-94, and issuance of Joint Flight Standards Information Bulletin for Air Transportation 00-02 and General Aviation 00-01, the FAA has completed the work recommended. Consequently, Safety Recommendation A-98-101 is classified "Closed-Acceptable Action.

From: FAA
To: NTSB
Date: 10/26/2005
Response: Letter Mail Controlled 10/27/2005 2:12:40 PM MC# 2050501 Marion C. Blakey, Administrator, FAA, 10/26/05 In 1999 and 2000, the FAA issued a series of 20 ADs mandating immediate use of deicing boots at the first sign of ice formation anywhere on the aircraft or upon alert of the ice detector system, whichever occurs first. The ADs applied to the following airplane types: Aerospatiale Models ATR-42 and ATR-72, Bombardier Models DHC-7 and DHC-8, British Aerospace Model HS 748, CASA Models C-212 and CN-235, Cessna Models 425 and 441, Dornier Model Dornier 328-100, Fairchild Models SA226, SA227, F27 and FH227, Fokker Model F27 Mark 100, 200, 300, 400, 500, 600 and 700 series aircraft, and Fokker Model F27 Mark 050, Gulfstream Aerospace Model G-159, Gulfstream American (Frakes Aviation) Models G-73 (Mallard) and G-73T, Jetstream Model BAe ATP, Lockheed Models L-14 and L-18 and Models 1329-23 and 1329-25, McDonnell Douglas Models DC-3 and DC-4, Mitsubishi Models YS-11 and YS-1 IA, Saab Models SF-340A, 340B, and Saab 2000, Sabreliner Models NA-265-40, NA-265-60, and NA-265-80, and Short Brothers Models SD3-30, SD3-60, SD3-Sherpa, and SD3-60 Sherpa. Similar ADs had been proposed for the Cessna Models 500,501,550,551, and 560 and Jetstream Model 4101 airplanes, but were withdrawn based on testing and substantiation that these airplanes are safe for operations with ice accretions on the deicing boots. The FAA recently conducted another review of operating procedures and information available to the flightcrew for minimum maneuvering speed information, including the use of increased speeds in icing conditions. On August 9, 2004, the FAA provided a comprehensive summary of this review in response to Safety Recommendation A 98-94 at the "Safety With A Team" meeting. The FAA looks forward to hearing the Board's position on the comprehensive summary. The FAA found that the manufacturers provide sufficient maneuvering speed information accessible to the flightcrew covering all phases of flight and airplane configurations for both icing and non-icing conditions. The means to convey the maneuvering speed information to pilots include flight deck displays, flight management systems, quick reference handbooks, flightcrew operating manuals, flightcrew training manuals, and Airplane Flight Manuals. In consideration of the information above, the FAA no longer intends to pursue the rulemaking referenced in our previous responses that would have mandated retroactive application of minimum operating speed requirements for icing conditions. The FAA's position regarding the disengagement of autopilot systems before entering icing conditions is detailed in response to Safety Recommendation A-98-97, which recommended that we require all operators of turbopropeller-driven air carrier airplanes to require pilots to disengage the autopilot and fly the airplane manually when they activate the anti-ice systems. On February 17, 2000, we issued Joint Flight Standards Information Bulletin for Air Transportation 00-02 and General Aviation 00-01, "Use of Autopilot During In-Flight Icing Conditions for Turbopropeller-Driven Airplanes." This bulletin directs principal operations inspectors to ensure that the information and procedures in the bulletin and any other approved pilot training for operations during in-flight icing are provided to each air carrier and included in the carrier's training program. The information should include guidance on the use of the autopilot in icing conditions and procedures to check for unusual trim forces and aircraft response. If disconnecting the autopilot is an approved procedure, the guidance to pilots should address the conditions under which this should be done. Furthermore, the FAA issued additional ADs that prohibit use of the autopilot in severe icing conditions that exceed the capability of the airplane's ice protection system. These ADs were applicable to the same airplanes as the ADS mandating immediate use of the deicing boots except that the Cessna Models 500, 501, 550, 551, and 560, Jetstream Model 4101, and Embraer Model 120 airplanes were included, and the Lockheed Models 1329-23 and 1329-25 were excluded. A list of these ADS is enclosed for the Board's information.

From: NTSB
To: FAA
Date: 7/11/2002
Response: The FAA's action is responsive to Safety Recommendation A-98-101. Pending rulemaking to address the retroactive application of minimum operating speeds appropriate for the safe operation of turbopropeller-driven airplanes in icing conditions and to prohibit the use of autopilots in icing conditions, Safety Recommendation A-98-101 remains classified "Open--Acceptable Response."

From: FAA
To: NTSB
Date: 9/21/2001
Response: Letter Mail Controlled 10/22/2001 11:44:27 AM MC# 2010866 The FAA is initiating rulemaking action to address the retroactive application of minimum operating speeds appropriate for the safe operation of turbopropeller-driven airplanes in icing conditions. An integral part of this rulemaking action will be to require the resulting operating speeds for icing conditions to be included in the Airplane Flight Manuals and Flight Crew Operating Manuals of the affected airplanes. I will keep the Board informed of the FAA's progress on this safety recommendation.

From: NTSB
To: FAA
Date: 3/12/2001
Response: The actions being taken by the FAA are responsive to this recommendation. However, regardless of the discussions held at the February 1999 In-flight Icing Conference, the Safety Board believes that accident experience has shown that the autopilot should not be used in icing conditions. Pending rulemaking action to address the retroactive application of minimum operating speeds appropriate for the safe operation of turbopropeller-driven airplanes in icing conditions and to prohibit the use of autopilots in icing conditions, Safety Recommendation A-98-101 remains classified Open--Acceptable Response.

From: FAA
To: NTSB
Date: 9/25/2000
Response: Letter Mail Controlled 10/02/2000 3:16:36 PM MC# 2001437 The FAA has evaluated the information obtained at the February 2-4, 1999, In-Flight Icing Conference, which was attended by airframe manufacturers, airline operators, worldwide civil aviation authorities, and other aviation organizations. Following the evaluation, the FAA issued AD 99-19-14 to require a revision to the Airplane Flight Manual operating procedures to require activation of deicing boots at the first sign of ice accretion anywhere on the airframe for turbopropeller-powered airplanes with pneumatic de-icing boots. Flight Standards Handbook Bulletin for Air Transportation 99-07 addressed incorporating similar revisions to Flight Crew Operating Manuals. The FAA is initiating rulemaking action to address the retroactive application of minimum operating speeds appropriate for the safe operation of turbopropeller-driven airplanes in icing conditions. An integral part of this rulemaking action will be to require the resulting operating speeds for icing conditions to be included in the Airplane Flight Manuals and Flight Crew Operating Manuals of the affected airplanes. It is anticipated that the rulemaking project will be approved by the end of 2000. Autopilot operation in icing conditions and whether or not it should be prohibited for airplanes with certain design characteristics was discussed at the February 1999 FAA In-Flight Icing Conference. The FAA is currently formulating action plans to address this issue. I will keep the Board informed of the FAA's progress on this safety recommendation.

From: NTSB
To: FAA
Date: 3/9/2000
Response: THE SAFETY BOARD ENCOURAGES THE FAA TO EXPEDITE ITS REVIEW OF THIS SAFETY CONCERN AND TAKE APPROPRIATE ACTION. PENDING COMPLETION OF THAT REVIEW AND SUBSEQUENT ACTION, A-98-101 IS CLASSIFIED "OPEN--ACCEPTABLE RESPONSE."

From: FAA
To: NTSB
Date: 2/26/1999
Response: ON 10/1/98, THE FAA ISSUED LETTERS REQUESTING MANUFACTURERS OF TURBOPROPELLER-POWERED TRANSPORT-CATEGORY AIRCRAFT TO SUBMIT COPIES OF EXISTING AFM LIMITATIONS AND PROCEDURES RELATED TO OPERATION IN ICING CONDITIONS INCLUDING PROCEDURES RELATED TO OPERATION OF THE AUTOPILOT DURING ICING CONDITIONS. IN JANUARY 1999, FAA SPECIALISTS MET TO ENSURE THE USE OF CONSISTENT REVIEW CRITERIA AND TO REACH A PRELIMINARY POSITION ON WHETHER OR NOT MANDATORY ACTION TO MODIFY THE AFM'S IS WARRANTED. THE FAA HELD AN IN-FLIGHT ICING CONFERENCE FEBRUARY 2-4, 1999, WITH AIRFRAME MANUFACTURERS, AIRLINE OPERATORS, WORLDWIDE CIVIL AVIATION AUTHORITIES, AND OTHER AVIATION ORGANIZATIONS. AT THE CONFERENCE, INFORMATION WAS EXCHANGED ON VARIOUS TOPICS INCLUDING THE ACCEPTABILITY OF ACTIVATING THE AIRFRAME DEICING SYSTEMS AT THE FIRST SIGN OF ICING CONDITIONS, USE OF THE AUTOPILOT IN ICING CONDITIONS, AND MINIMUM SPEEDS IN ICING CONDITIONS. THE FAA WILL EVALUATE THE INFORMATION OBTAINED AT THE CONFERENCE TO DETERMINE IF MANDATORY ACTION NEEDS TO BE TAKEN REGARDING AFM CHANGES. I WILL KEEP THE BOARD INFORMED OF THE FAA'S PROGRESS ON THIS RECOMMENDATION.