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Safety Recommendation Details

Safety Recommendation A-98-108
Details
Synopsis: Information 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, and 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 and 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, and (7) 6/28/89, Embraer EMB- 120, Klamath Falls, Oregon.
Recommendation: TO THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION: With the FAA and other interested aviation organizations, conduct additional research to identify realistic ice accumulations, to include intercycle and residual ice accumulations and ice accumulations on unprotected surfaces aft of the deicing boots, and to determine the effects and criticality of such ice accumulations; further, the information developed through such research should be incorporated into aircraft certification requirements and pilot training programs at all levels.
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: 1/31/2011
Addressee(s) and Addressee Status: National Aeronautics and Space Administration (Closed - Acceptable Action)
Keyword(s): Icing, Weather

Safety Recommendation History
From: NTSB
To: National Aeronautics and Space Administration
Date: 1/31/2011
Response: The NTSB is familiar with the excellent research program on aircraft icing conducted by NASA. On June 29, 2010, the FAA published a notice of proposed rulemaking to revise airplane and engine certification requirements in supercooled large drop, mixed phase, and ice crystal icing conditions; the basis for these revisions was largely the result of icing research conducted by NASA. The issue of in-flight aircraft icing is of great interest to the NTSB and has been included on our Most Wanted List for many years. Because the specific action recommended has been completed, Safety Recommendation A-98-108 is classified “CLOSED -- ACCEPTABLE ACTION,” but, because of our continued interest in this issue, we urge NASA to continue full support of its research program.

From: National Aeronautics and Space Administration
To: NTSB
Date: 10/15/2010
Response: MC# 201000398: - From Charles F. Bolden, Jr., Administrator: I am pleased to respond to your request for information on the research conducted by the National Aeronautics and Space Administration (NASA) related to aircraft inflight icing and, specifically, our efforts in response to NTSB safety recommendation A-98-l08. In response to recommendation A-98-l08, NASA collaborated with the Federal Aviation Administration (FAA) on two separate, yet related, research projects. In the first study, NASA collaborated with the FAA by jointly investigating the effects of residual and inter-cycle ice accretions on airfoil performance. This study, documented in FAA Report DOTIFAAJAR-02/68, concluded that inter-cycle ice accretions tended to be larger than residual ice accretions, and that the intercycle ice accretions produced the greater aerodynamic penalty. This research effort also concluded that pneumatic boot deicing systems were effective in cleaning the leading edge of the airfoil tested. Finally, the investigation also determined that activation of the boot at the onset of icing (which had been the standard practice of the industry at the time) was just as effective in clearing ice from the surface as activation after a quarter inch of ice had been allowed to accumulate. In the second study, NASA and the FAA collaborated, along with other organizations, on an examination of the performance of pneutnatic deicing boots. That research effort examined the use of subscale models for testing of pneumatic deicing boots and verified the previous studies' conclusions that pneumatic boots should be activated at the onset of icing and should be operated in automatic cycling mode. The results of this study were reported in FAA Report DOTIFAAJAR-06/48. With the publication of these reports, NASA considers the work requested by the NTSB in recommendation A-98-l08 to have been completed. The FAA has incorporated information from these efforts into the certification process through the release of Advisory Circular AC 25-25 titled, Performance and Handling Characteristics in the Icing Conditions Specified in Part 25, Appendix C. Regarding the FAA Notice for Proposed Rulemaking (NPRM), NASA has conducted and continues to support a robust program of icing research investigating the physics of ice accretion resulting from exposures to Super-cooled Large Droplet (SLD), mixed phase, and ice crystal conditions. As you know, the NPRM has its origins in the 1994 crash of American Eagle Flight 4184, an ATR-72, in Roselawn, Indiana. Immediately following that crash, NASA participated in the investigation of the accident at the request of the NTSB. In the years that followed, NASA led an industry-wide effort to investigate SLD icing, from the characterization of the enviromnental conditions leading to SLD to the development of test methods and computational tools for simulation of SLD conditions and their effect on aircraft performance. NASA collaborated closely with the FAA during that period to provide the technical information underlying the icing physics and simulation elements contained within the NPRM. NASA continues to investigate SLD icing physics and simulation under its Aviation Safety Program. NASA also participated, as a technical consultant, in the FAA Aviation Rulemaking Advisory Committee (ARAC) through the Engine Harmonization Working Group, the Ice Protection Harmonization Working Group, and the Flight Test Harmonization Working Group. The ARAC provided the information required by the FAA to go forward with the NPRM. Another outcome of the ARAC activities was the identification of ice crystal ingestion by turbofan engines at high altitudes as a potential threat. That led NASA to support research efforts on the impact of ice crystal ingestion on the performance of turbofan engines. NASA is making a significant investment, along with the FAA and others, on a flight campaign designed to characterize the nature of atmospheric conditions leading to ice crystal formation, as well as to define the envelope ofsuch conditions that might be used for future rulemaking and subsequent certification efforts. In addition to this flight campaign; NASA is investing in modifications to the Propulsion Systems Laboratory, located at the Glenn Research Center, to allow simulation of ice crystal ingestion, at flight altitudes, in a ground-based engine test facility. Finally, NASA is also collaborating with the FAA and the National Research Council of Canada on several experimental research activities designed to understand the processes leading to ice accumulation within the compressor section of a modem turbofan engine. As you can see, NASA continues to support a myriad of research efforts focused on the investigation of physical processes related to ice accretion. NASA also continues to support the development of experimental and computational tools designed to aid in the analysis of ice accretion on airframe and engine components, as well as assessment of the impact of such accretions on the performance of vehicles encountering icing. I hope this addresses the status of NTSB safety recommendation A-98-1 08 and provides you with a satisfactory update on our current icing research plans. If you need additional information on this subject, please feel free to contact me.

From: NTSB
To: National Aeronautics and Space Administration
Date: 8/19/2010
Response: NMC# 103443: NASA’s most recent letter to the NTSB regarding this recommendation is dated October 19, 2000. The NTSB is currently reviewing a notice of proposed rulemaking (NPRM) published by the FAA on June 29, 2010, titled “Airplane and Engine Certification Requirements in Supercooled Large Drop, Mixed Phase, and Ice Crystal Icing Conditions,” which appears to be based on the recommended research. Accordingly, please provide the NTSB an update of any current icing research NASA is conducting, or inform us if NASA considers its work in response to this recommendation completed. Thank you for your cooperation.

From: NTSB
To: National Aeronautics and Space Administration
Date: 8/19/2004
Response: NASA's letter did not include any new information on actions taken in response to this safety recommendation. A companion recommendation, A-98-92, was issued to the FAA. Safety Recommendation A-98-92, along with several other recommendations concerning the reduction of dangers to aircraft flying in icing conditions, is on the Safety Board's Most Wanted list. The Board considers research on freezing rain and large water droplets and the modifications to aircraft design and operating procedures resulting from that research to be a critical need in the efforts to reduce aviation transportation accidents due to icing conditions and to save lives. The Safety Board urges NASA, in conjunction with the FAA, to continue and, if possible, expedite research in this area. The Board would appreciate an update on this research before our November 2004 Board meeting, when the icing-related recommendations on the Most Wanted list will be reviewed. Pending that updated information, Safety Recommendation A-98-108 remains classified OPEN -- ACCEPTABLE RESPONSE.

From: National Aeronautics and Space Administration
To: NTSB
Date: 3/3/2004
Response: Letter Mail Controlled 3/15/2004 9:38:45 AM MC# 2040117 - From Sean O'Keefe, Administrator: NASA lists this recommendation jointly with A-98-107, but all action described is in response to -107. There is no mention of research in response to the recommendation. "The information provided to Mr. Marcus should be sufficient to satisfy the recommendations listed. Please advise us if more information is required."

From: NTSB
To: National Aeronautics and Space Administration
Date: 12/10/2003
Response: NMC# 102335: The Safety Board's records indicate that the most recent correspondence from NASA concerning these recommendations was dated October 19, 2000. In this correspondence, NASA indicated that, regarding Safety Recommendation A-98-107, it had produced two training videos on icing and was planning to produce another, as well as a computer-based training module, for general aviation pilots. Regarding Safety Recommendation A-98-108, NASA indicated that it intended to conduct additional testing in a dry-air tunnel in fiscal year 2001. NASA stated that this testing was in support of the FAA and would eventually provide a better understanding of residual ice and small ice accumulations for incorporation in training materials. Based on NASA's plans, Safety Recommendations A-98-107 and -108 were classified OPEN -- ACCEPTABLE RESPONSE, pending NASA's development of the additional training materials and completion and analysis of the additional testing. The Safety Board would appreciate receiving an update from NASA regarding actions taken to address Safety Recommendations A-96-14, A-98-107, and A-98-108.

From: NTSB
To: National Aeronautics and Space Administration
Date: 3/12/2001
Response: NASA reports that it is working with the FAA on a Residual Ice/Intercycle Ice research project that was initiated in Fiscal Year (FY) 1999. In FY 2000, two tests were conducted in an icing wind tunnel to examine residual ice characteristics. NASA reports that, in FY 2001, a follow-on test will be conducted in a NASA dry?air wind tunnel to catalogue the aerodynamic effects. Pending completion of the wind tunnel tests and analysis of the aerodynamic effects of residual ice and small ice accumulations, Safety Recommendation A-98-108 remains classified OPEN -- ACCEPTABLE RESPONSE.

From: National Aeronautics and Space Administration
To: NTSB
Date: 10/19/2000
Response: Letter Mail Controlled 11/01/2000 8:13:05 AM MC# 2001575 - From Daniel S. Goldin, Administrator: ·NASA is working as a technical advisor to the FAA, the principal investigator for this recommendation, on a Residual Ice/Intercycle Ice project that was initiated in FY1999. · The work is a collaborative effort between both agencies, with representation from an ice protection manufacturer and two airframe manufacturers. At NASA, the work is conducted by the Icing Research group at our Glenn Research Center and is supported by their subject matter experts and facilities that incorporate results from the Icing Research Tunnel and the Icing Research Aircraft. · In FY2000, two tests have been conducted in an icing wind tunnel to examine the residual ice characteristics, and a follow-on test will be conducted in FY2001 in a NASA dry-air tunnel test will catalogue the aerodynamic effects. · This work will eventually provide the basis for a better understanding of residual ice and small ice accumulations and be included in training materials. · The work supporting A?98?108 is led by and predominantly funded by the FAA. NASA has supplied some funding, but principally provides test materials and subject matter experts.

From: NTSB
To: National Aeronautics and Space Administration
Date: 7/26/2000
Response: NMC # 100362: The Board's records indicate that the most recent correspondence from NASA concerning these recommendations was dated 1/13/99. The Safety Board would appreciate learning of any further actions NASA has taken or intends to take to address A-88-19, A-96-14, A-98-107, and A-98-108.

From: NTSB
To: National Aeronautics and Space Administration
Date: 3/12/1999
Response: A-98-108 asked NASA, along with the FAA and other interested aviation organizations, to conduct additional research to identify realistic ice accumulations, including intercycle and residual ice accumulations and ice accumulations on unprotected surfaces aft of the deicing boots, and determine the effects and criticality of such ice accumulations; further, the information developed through such research should be incorporated into aircraft certification requirements and pilot training at all levels. Pending more detailed information on NASA's education materials and research regarding icing conditions, A-98-107 and -108 are classified OPEN – ACCEPTABLE RESPONSE.

From: National Aeronautics and Space Administration
To: NTSB
Date: 1/13/1999
Response: Letter Mail Controlled 02/19/1999 10:02:22 AM MC# 990021 - From Daniel S. Goldin, Administrator: NASA is well positioned to fulfill A-98-107 and -108. NASA, the FAA, and other aviation organizations will work together to develop and implement a plan to aggressively pursue an industry-wide training program on the hazards of icing. Additionally, NASA will work with these same organizations to increase understanding of the adverse effects of ice accumulations on aircraft. Nasa and the faa are partners in the joint safety working group (SWG) specifically to address issues in research and development in aviation safety. The SWG coordinates efforts for both agencies in this field, and that coordination, essential to the functioning of NASA's aviation safety program office, will provide the focus for responding to the recommendations. The FAA's flight standards and aircraft certification services have taken the lead in a weather-accident prevention training effort by setting up a workshop on in-flight operations and icing conditions. NASA's aviation safety program office will participate in that workshop. NASA will work with the FAA and other interested aviation organizations to develop educational materials that will focus on the hazards, technology, and operational procedures associated with conducting flight operations during icing conditions. An important part of NASA's investment in aviation safety research is weather-related. NASA will examine its research plans to ensure that an understanding of the effects and criticality of ice accumulations is aggressively pursued. Knowledge gained from this research will be provided to the FAA for incorporating in aircraft certification requirements and pilot training programs. NASA will work closely with the FAA across many different organizational levels to address the problems of aircraft safety, such as icing. After collaboration with the FAA, we will provide your staff with a more detailed approach to satisfy A-98-107 and -108.