Accident involving turbulence and Aer Arann ATR-42-300 on descent to Donegal International Airport, Ireland, on December 2, 2001. Micro-summary: On descent, this ATR-42 encountered turbulence, injuring several people. Event Date: 2001-12-02 at 1300 UTC Investigative Body: Air Accident Investigation Unit (AAIU), Ireland Investigative Body's Web Site: http://www.aaiu.ie/ 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 FINAL REPORT AAIU Report No.:2002/007 AAIU File No.: 2001/0072 Published: 12 July 2002 Operator: Aer Arann Manufacturer: ATR Model: ATR 42-300 Nationality Irish Registration EI-CPT Location Mt Errigal, Co. Donegal Date/Time (UTC) 2 Dec 2001 at 1300 hrs SYNOPSIS. The aircraft departed from Dublin Airport (EIDW) for Donegal International Airport (EIDL) at Carrickfin, Co. Donegal at 12.23 hrs. At 2700 ft Above Sea Level (ASL), during the descent to land, the aircraft experienced severe turbulence. One of the crew and two passengers were reported injured during this event. The aircraft landed, as intended, on Runway (RWY) 21. The passengers and crew disembarked and a medical doctor attended the injured. NOTIFICATION The Operator informed an inspector of the Air Accident Investigation Unit directly, following this serious incident. The Chief Inspector of Accidents nominated Mr. John Hughes, an Inspector of Accidents, to investigate the event and to compile a report. The inspector arrived in Donegal at 17.00 hrs the same day and commenced the investigation. The inspector was later informed that one of the passengers on the aircraft had been hospitalised for more than 48 hours. The serious incident thus became an accident under the Regulations set out in Statutory Instrument S.I. No.205 of 1997. 1. FACTUAL INFORMATION 1.1 History of the Flight. Flight REA 201 took off from EIDW at 12.15 with a crew of three and 32 passengers. Prior to descent, the flight to was uneventful. It was a bright clear day with visibility greater than 10 kilometres. The aircraft passed over the Glendowan Mountain range and at approx 5000 ft commenced an extended left hand downwind approach to RWY 21. At about 10 nm SE of the threshold and approximately 7 minutes to run, the aircraft experienced severe turbulence. The turbulence lasted for about 10 seconds. The cabin attendant and two passengers were injured. On arrival at EIDL all three were examined by a doctor at the airport. One of the passengers was hospitalised and the other released. A technical examination of the aircraft was completed at the airport and the aircraft was later ferried back, without passengers, to EIDW. 1.1.1 Captain’s Report In his report, the Captain stated: “We were in VMC conditions throughout the entire flight (See Chart Appendix A). EIDL Airfield was visible from 30 miles out. I started the descent by positioning the aircraft for a visual left base to Runway 21. The actual weather conditions obtained from EIDL confirmed my visual observations, steady without wind (no gusts), no cloud, unlimited visibility and good temperature spread (+7/+3), (benign conditions). On descent and on clearing the high ground we experienced severe turbulence. During this encounter the First Officer’s hand had inadvertently hit switches on the overhead panel causing all cockpit lights to illuminate. After the accident the subsequent approach and landing was normal.” His assessment of the cause of the accident was: “With hindsight, clear air turbulence in the lee of high ground. The free wind, i.e. the forecast conditions, 200/30 @ 1000ft and 200/35 @ 5000ft would not indicate the possibility of such conditions. Also clear sky, no orographic cloud and no cloud with vertical displacement.” The Captain, who was the handling pilot on the flight, in an interview with the investigator said that it was a bright clear day. He could see Belfast, which was 53 miles away. He said the aircraft was at 2000 ft, having just passed over the mountains, when the aircraft experienced severe turbulence for about 10 seconds. Following the accident the Captain called out to the cabin attendant, who was at the time in the forward baggage area, to go and check the passengers. On hearing that one of them was injured he decided to radio ahead to have a doctor present on arrival. The Captain said that he was carrying out a visual approach on a left turn onto the runway heading. In doing so he said that he would have maintained a constant distance from the runway threshold whilst at the same time turning the aircraft on to the runway heading. This procedure would have taken him over the Derryveagh mountain range. His was the first aircraft into EIDL that day and as the day was very clear, he was not expecting turbulence. There was absolutely no warning. He remembered hitting his head off the cockpit ceiling. Following the issue of the Draft Report, the Captain made some representations, which included the following: “I refer to the fact that during this incident the first officer’s hand inadvertently hit switches on the overhead panel causing all the cockpit lights to illuminate. This indicated a catastrophic failure. This was not the case but such an indication could have led to actions, which could have had very serious consequences. Consideration should be given to informing crew of the possibility of inadvertent activation of the annunciator switch and the possible misleading indications.” 2 1.1.2 Co-Pilots Report The Co-Pilot was also interviewed and he concurred with what the Captain had said. He said that the seat belt sign had been put on as part of the descent checks. He said that the duration of the turbulence felt more like 3 seconds than 10 seconds. He was pushed upwards in his seat and struck his head. His hand struck the overhead panel. As he did so his hand caught the annunciator lights test switch and all the panel overhead lights came on. Afterwards he noticed that his seat belt had opened. The Co-pilot said that he had attended a one-day Cockpit Resource Management (CRM) course at Toulouse and a 4-day Multi-Crew Coordination (MCC) course at Heathrow on a Kingair 200 aircraft. 1.1.3 Cabin Attendant’s Report The Cabin Attendant said that she had just finished the refreshment service and had locked the cart in the storage area. She went to the cockpit at the Captain’s request. She was about to reverse from the cockpit area with glasses in her hand when suddenly she was thrown backwards and her feet went forward and upwards. She was in the small baggage area between the cockpit and the cabin. The door to the cockpit was open but the door to the passenger cabin was closed. The Captain called out to her to look after the passengers, not realising that she had fallen. The first thing she noticed was that all the overhead annunciator lights were on, which was not normal. She said that during the turbulence, she struck the top of the cockpit doorframe with her legs and then fell to the floor. She used the baggage netting to haul herself up from the floor. She then opened the door between the baggage area and the cabin and went through to look after the passengers. The Captain called her on her cabin interphone system and she reported that one of the passengers would require medical attention. In conjunction with one of the passengers, who was medically trained, she rendered assistance to the injured passenger and helped to refasten his seat belt. 1.1.4. Passenger Witness Reports (a) A passenger who sustained arm, shoulder and back injuries with a suspected fracture of the humerus said that, following the turbulence, he was rendered unconscious for a short duration. En-route to Donegal whilst the aircraft was over the Cavan area he felt it bank to starboard. He checked his seat belt to make sure it was fastened. He had been worried about the seat belt as it did not seem to tighten very well. He said that later the aircraft was quite low and he was looking out at Dunlewy Lough, which is situated at the south base of Mt. Errigal. He thought that there was a whisper of cloud resting on the top of the mountain. The aircraft suddenly dipped to port and then banked to starboard. There was a terrible noise coming from up front and he then lost consciousness.