F PB96-91040I NTSB/AAR-96/01 DCA95MA001 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 AIRCRAFT ACCIDENT REPORT IN-FLIGHT ICING ENCOUNTER AND LOSS OF CONTROL SIMMONS AIRLINES, d.b.a. AMERICAN EAGLE FLIGHT 4184 AVIONS de TRANSPORT REGIONAL (ATR) MODEL 72-212, N401AM ROSELAWN, INDIANA OCTOBER 31,1994 VOLUME 1: SAFETY BOARD REPORT 6486C The National Transportation Safety Board is an independent Federal agency dedicated to promoting aviation, railroad, highway, marine, pipeline, and hazardous materials safety. Established in 1967, the agency is mandated by Congress through the Independent Safety Board Act of 1974 to investigate transportation accidents, determine the probable causes of the accidents, issue safety recommendations, study transportation safety issues, and evaluate the safety effectiveness of government agencies involved in transportation. The Safety Board makes public its actions and decisions through accident reports, safety studies, special investigation reports, safety recommendations, and statistical reviews. Information about available publications may be obtained by contacting: National Transportation Safety Board Public Inquiries Section, RE-51 490 L’Enfant Plaza, S.W. Washington, D.C. 20594 (202)382-6735 (800)877-6799 Safety Board publications may be purchased, by individual copy or by subscription, from: National Technical Information Service 5285 Port Royal Road Springfield, Virginia 22161 (703)487-4600 NTSB/AAR-96/01 PB96-910401 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 AIRCRAFT ACCIDENT REPORT IN-FLIGHT ICING ENCOUNTER AND LOSS OF CONTROL SIMMONS AIRLINES, d.b.a. AMERICAN EAGLE FLIGHT 4184 AVIONS de TRANSPORT REGIONAL (ATR) MODEL 72-212, N401AM ROSELAWN, INDIANA OCTOBER 31, 1994 Adopted: July 9, 1996 Notation 6486C Abstract: Volume I of this report explains the crash of American Eagle flight 4184, an ATR 72 airplane during a rapid descent after an uncommanded roll excursion. The safety issues discussed in the report focused on communicating hazardous weather information to flightcrews, Federal regulations on aircraft icing and icing certification requirements, the monitoring of aircraft airworthiness, and flightcrew training for unusual events/attitudes. Safety recommendations concerning these issues were addressed to the Federal Aviation Administration, the National Oceanic and Atmospheric Administration, and AMR Eagle. Volume II contains the comments of the Bureau Enquetes-Accidents on the Safety Board's draft of the accident report. CONTENTS EXECUTIVE SUMMARY................................................................ vii 1. FACTUAL INFORMATION 1.1 History of Flight................................................................................... 1 1.2 Injuries to Persons................................................................................ 12 1.3 Damage to Airplane ............................................................................. 12 1.4 Other Damage ...................................................................................... 12 1.5 Personnel Information.......................................................................... 12 1.5.1 The Captain .......................................................................................... 12 1.5.2 The First Officer................................................................................... 13 1.5.3 The Flight Attendants .......................................................................... 14 1.5.4 Air Traffic Control Personnel.............................................................. 14 1.5.4.1 DANVILLE Sector Controller............................................................. 14 1.5.4.2 BOONE Sector Controller ................................................................... 15 1.5.4.3 BOONE Sector Developmental Controller ......................................... 15 1.6 Airplane Information ........................................................................... 15 1.6.1 Flight 4184 Dispatch Weight and Balance Information...................... 17 1.6.2 ATR 72 Wing Design History ............................................................. 17 1.6.3 ATR 72 Lateral Flight Control System Description ........................... 18 1.6.3.1 ATR 72 Directional Flight Control System......................................... 21 1.6.4 ATR 72 Stall Protection System.......................................................... 23 1.6.5 Autoflight System Description ............................................................ 24 1.6.6 ATR 72 Ice and Rain Protection Systems ........................................... 25 1.6.7 ATR 42/72 Type Certification History................................................ 30 1.6.7.1 General ................................................................................................. 30 1.6.7.2 ATR 72 Icing Certification Program ................................................... 30 1.6.7.3 Postaccident Certification Review....................................................... 35 1.7 Meteorological Information................................................................. 44 1.7.1 General ................................................................................................. 44 1.7.2 Flight 4184 Dispatch Weather Information......................................... 45 1.7.3 Weather Synopsis................................................................................. 48 1.7.4 Pilot Reports (PIREPs) and Other Weather Information .................... 53 1.7.4.1 Witness Descriptions of Weather Conditions ..................................... 54 1.7.5 Hazardous In-flight Weather Advisory Service (HIWAS) ................. 57 1.7.6 Information About Freezing Rain/Freezing Drizzle and General Icing Conditions .......................................................................................... 57 1.7.7 Classification of Icing Conditions ....................................................... 60 iii 1.7.8 Forecasting of In-flight Icing Conditions............................................ 61 1.8 Aids to Navigation ............................................................................... 63 1.9 Communications .................................................................................. 63 1.10 Aerodrome Information ....................................................................... 63 1.11 Flight Recorders................................................................................... 63 1.11.1 Cockpit Voice Recorder....................................................................... 63 1.11.2 Digital Flight Data Recorder................................................................ 64 1.12 Wreckage and Impact Information ...................................................... 64 1.12.1 General Wreckage Description............................................................ 64 1.12.2 The Wings ............................................................................................ 67 1.12.3 Empennage........................................................................................... 71 1.12.4 Engines and Propellers......................................................................... 72 1.13 Medical and Pathological Information ................................................ 73 1.14 Fire ....................................................................................................... 73 1.15 Survival Aspects .................................................................................. 73 1.16 Tests and Research............................................................................... 74 1.16.1 ATR 42/72 Lateral Control System Development History................. 74 1.16.2 Previous ATR 42/72 Incidents/Accidents ........................................... 75 1.16.3 Communication of Airworthiness Information Between FAA, DGAC and ATR................................................................................. 88 1.16.4 Investigation of Lateral Control System Behavior.............................. 91 1.16.5 Postaccident NASA Icing Research .................................................... 92 1.16.6 ATR 72 Icing Tanker Tests.................................................................. 94 1.16.7 Historical Aspects of Icing Research and Aircraft Icing Certification Requirements ..................................................................................... 97 1.17 Organizational and Management Information..................................... 100 1.17.1 Simmons Airlines................................................................................. 100 1.17.2 AMR Eagle Organization .................................................................... 101 1.17.3 FAA Oversight of Simmons Airlines/AMR Eagle.............................. 103 1.17.4 FAA Partnership in Safety Program.................................................... 103 1.17.5 Simmons Airlines/AMR Eagle Pilot Training .................................... 104 1.17.5.1 General Training Information.............................................................. 104 1.17.5.2 AMR Eagle Flight Training................................................................. 106 1.17.6 Flight and Airplane Operating Manual................................................ 107 1.17.7 Unusual Attitude and Advanced Maneuvers Training........................ 117 1.18 Additional Information ........................................................................ 118 1.18.1 Air Traffic Control..............................................................................