Tailcone Loss in Climb, Air Canada, Mcdonnell Douglas DC-9-32 (CF-TLU), East of Boston, Massachusetts, September 17, 1979
Total Page：16
File Type：pdf, Size：1020Kb
Tailcone loss in climb, Air Canada, McDonnell Douglas DC-9-32 (CF-TLU), East Of Boston, Massachusetts, September 17, 1979 Micro-summary: During climb, the tailcone and aft cabin access door on this DC-9 fell off, prompting a return back to the origin. Event Date: 1979-09-17 at 1212 EDT Investigative Body: National Transportation Safety Board (NTSB), USA Investigative Body's Web Site: http://www.ntsb.gov/ Cautions: 1. Accident reports can be and sometimes are revised. Be sure to consult the investigative agency for the latest version before basing anything significant on content (e.g., thesis, research, etc). 2. Readers are advised that each report is a glimpse of events at specific points in time. While broad themes permeate the causal events leading up to crashes, and we can learn from those, the specific regulatory and technological environments can and do change. Your company's flight operations manual is the final authority as to the safe operation of your aircraft! 3. Reports may or may not represent reality. Many many non-scientific factors go into an investigation, including the magnitude of the event, the experience of the investigator, the political climate, relationship with the regulatory authority, technological and recovery capabilities, etc. It is recommended that the reader review all reports analytically. Even a "bad" report can be a very useful launching point for learning. 4. Contact us before reproducing or redistributing a report from this anthology. Individual countries have very differing views on copyright! We can advise you on the steps to follow. Aircraft Accident Reports on DVD, Copyright © 2006 by Flight Simulation Systems, LLC All rights reserved. www.fss.aero b NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 AIRCRAFT ACCIDENT REPORT AIR CANADA McDONNELL-DOUGLAS DC-9-32 (CF-TLU) EAST OF BOSTON, MASSACHUSETTS SEPTEMBER 17, 1979 UNITED STATES GOVERNMENT CONTENTS SYNOPSIS ........................... 1 1.FACTUALINFORMATION .................. 1 1.1 History of the Flight .................... 1 1.2 Injuries to Persons ..................... 3 1.3 Damage to Aircraft ..................... 3 1.4 Other Damage ....................... 3 1.5 Personnel Information .................... 3 1.6 Aircraft Information .................... 3 1.7 Meteorological Information .................. 3 1.8 Aids to Navigation ...........: ......... 4 1.9 Communications ...................... 4 1.10 Aerodrome Information ................... 4 1.11 Flight Recorders ...................... 4 1.12 Wreckage and Impact Information ............... 4 1.12.1 Fuselage Examination ................... 5 1.12.2 Flight and Engine Control Examination ............ 5 1.13 Medical and Pathological Information ............. 5 1.14 Fire ........................... 6 1.15 Survival Aspects ...................... 6 1.16 Tests and Research ..................... 6 1.16.1 Metallurgical Examination ................. 6 1.16.2 Test of the Oxygen System ................. 6 1.17 Other Information ...................... 8 1.17.1 Immediate Action of Air Canada .............. 8 1.17.2 Emergency Telegraphic Airworthiness Directive No . T79WE13 . 8 1.17.3 Emergency Telegraphic Airworthiness Directive No . T79WE15 . 9 1.17.4 ~irworthiness~irective 79-WE-30-AD; Amendment 39-3618 . 11 1.17.5 Results of Fleetwide Inspection ............... 13 1.18 Useful or Effective Investigation Techniques .......... 13 2.ANALYSIS .......................... 13 2.1 General .......................... 13 2.2 The Aft Pressure Bulkhead .................. 13 2.3 Inspection and Quality Control ................ 14 3 .CONCLUSIONS ........................ 15 3.1 Findings .......................... 15 3.2 Probable Cause ....................... 15 4 .SAFETY RECOMMENDATIONS ................. 16 5.APPENDIXES ........................ 17 Appendix A~Investigationand Hearing ............. 17 Appendix B~PersonnelInformation ............... 18 Appendix C~AircraftInformation ............... 19 NATIONAL TRANSPORTATION SAFETY BOARD WASHINGTON, D.C. 20594 AIRCRAFT ACCIDENT REPORT Adopted: January 30,1981 AIR CANADA McDONNELL DOUGLAS DC-9-32 (CF-TLU) EAST OF BOSTON, MASSACHUSETTS SEPTEMBER 17,1979 SYNOPSIS At 1212 e.d.t., on September 17, 1979, Air Canada Flight 680, a scheduled passenger flight to Yarmouth, Nova Scotia, Canada, departed Logan International Airport, Boston, Massachusetts. About 14 min after takeoff, at an altitude of about 25,000 ft m.s.l., the tailcone along with the aft cabin pressure access door and a portion of the aft cabin pressure bulkhead separatedfrom the aircraft causing rapid decompression of the passenger and flightcrew compartments. The aircraft was landed safely at Logan International Airport about 38 min after takeoff. Of the 45 persons aboard, one flight attendant received minor injuries during the decompression. The aircraft's oxygen system and its elevator control and engine control systems were damaged. The National Transportation Safety Board determines that the probable cause of the accident was a fatigue fracture of the aft cabin pressure bulkhead which resulted in a rapid decompression of the aircraft's cabin area. This fracture initiated from a crack below the aft bulkhead access door which was discernible on the X-rays taken during the aircraft's last maintenance inspection but was not detected by the inspectors. 1. FACTUAL INFORMATION 1.1 History of the Flight On September 17, 1979, Air Canada Flight 680, a McDonnell Douglas DC-9-32 (CF-TLU), operated as a scheduled passenger flight from Boston, Massachusetts, to Yarmouth, Nova Scotia, Canada. Flight 680 departed Logan International Airport at Boston at 1212, I/ with 45 persons, including 5 crewmembers, aboard. The flight was cleared to Yarmouth in accordance with an instrument flight rules (IFR) flight plan and was issued climb-out instructions. The assigned en route flight level (EL) 21 was 250. The flight was uneventful during the takeoff and most of the climb. ~llrequiredchecklist items were accomplished. -I/ All times herein are eastern daylight, based on the 24-hour clock. 21 Altitude and terrain elevation referred to in this report are above mean sea level, and all flight levels (FL) are above the standard datum plane. About 1226, shortly before Flight 680 leveled off at FL 250, a rapid decompression occurred. At 1226:08, the flight reported, "Boston Center, Air Canada 680 is doing a rapid emergency descent. Clearance back to Boston, we're out of twenty-three thousand, descending." The Boston Air Traffic Control Center cleared the flight to "turn right and proceed direct to Boston. Descend and maintain one four thousand. Boston altimeter three zero two four." The flight was then asked, "Are you going to need assistance?" At 1226:34, the flight advised Boston Center that it had experienced an explosive decompression, that it was out of 20,000 ft, and that it was requesting 9,000 ft for level off. The flight was cleared to continue descent and maintain 10,000 ft. At 1228:24, the flight responded, "Roger, we are just leveling now and the back end of our tail is blown completely off. If you could have some emergency crews standing by." The flight was then cleared to descend to 9,000 ft. At 1229, the flight cancelled the request for emergency crews and requested the closest runway for landing. At 1231, the flight again requested the emergency equipment and Boston Center advised "they've got the equipment out and runway three three left." The flight acknowledged the clearance for landing on runway 33L. At 1234:55, Boston center cleared the flight for descent to 4,000 ft. At 1237:58, the flight was cleared to Boston, "altitudes at your discretion." At 1239:38, Logan Arrival Radar asked the flight if there were any control problems. The flight responded, "negative." A visual approach was flown and a landing was made on runway 33L, at 1250, without further incident. During a postflight interview, the captain of Flight 680 reported that just before level-off at FL 250, an extremely loud bang was heard with complete loss of cabin pressurization. The first officer was flying the aircraft. "Rapid depressurizationt' was called and the first officer placed the aircraft on autopilot. The flightcrew donned their oxygen masks to make communication checks. The captain stated that he assumed control of the aircraft, started an emergency descent, and observed that the cockpit door was missing and that there was blue sky visible through the aft of the aircraft. He also observed that the passengerst oxygen masks had deployed, so he slowed the rate of descent. The purser advised that everybody was all right except for a flight attendant who had "a bump on her head." After level-off at 9,000 ft, the first officer went into the cabin to check on the passengers and crew. He reported that everyone was all right. The captain stated that the right throttle would not advance beyond 1.25 exhaust pressure ratio (EPR); however, at that power setting all engine parameters were normal and the hydraulic system was normal. The first officer added that the right pneumatic crossfeed valve lever had opened and could not be closed. The aircraft was purposely kept high during the approach for landing and the flaps and landing gear were used to reduce airspeed and altitude. The captain stated that this was done because of the limited use of the right engine. He also stated that the landing- was normal: however, the left engine could not be reversed after touchdown. 1.2 Injuries to Persons Injuries -Crew Passengers Others -Total Fatal 0