A database of technical and aerodynamic sounds in aviation

1. A database of technical and aerodynamic sounds in aviation Päivikki Eskelinen-Rönkä Department of Speech Sciences University of Helsinki

2. Aviation Intro • Industry of strict regulations: Personnel, technology, procedures • Organizations: ICAO, Eurocontrol, FAA, CAA … • Documentation: technology, procedures, ratings (pilots + cabin crew) etc. • Accident investigation principles in Annex 13 • To find the cause, not the guilty!

3. Recorders • Commercial aircrafts are equipped with Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR) BLACK BOXES • Separate or combined recorders are usually installed in the tail section • QAR, not crash survivable • Two storage mediums: • Analog: magnetic tape (30 min continuous) • Digital: memory chips (2 hrs/CVR – 25 hrs/FDR)

4. FDR • FDR collects information from different parameters, e.g. time, headings, altitudes, speeds, and movements of flight controls • Number of parameters: from 18 to over 1000 • Reconstruction of the flight: video animation

5. CVR • CVR records all speech and audio information in the cockpit and speech transmission systems • Several channels • CAM = Cockpit Area Microphone, AREA • All technical and aerodynamic sounds • Speech transmission, Channels 1-3 • ATC transmission + passenger briefing + “hot mike”

6. Accident investigation To determine the probable cause of the accident: • The recorders are located and removed • Emergency Locator Transmitter, ELT • Underwater Locator Beacon, ULB (37.5 KHz 14,000 ft) • Analysis of recovered and translated FDR and CVR data: • Animations, transcriptions (spectral analysis) • Separate investigations, tests etc. • Collecting of reference samples • Hearings, witness statements etc.

7. Problems with CVR and FDR analysis CVR • Unintelligible speech: changing noise levels and/or G-forces • Missing speech: unconsciousness, lack of CRM FDR • Slower sampling rate (e.g. 1-8 samples per sec) • Longer recording time (e.g. 25 - 33 hours of data) • Synchronization with CVR (absolute timing?) • No separation between PIC and COP • Malfunction

8. Without CVR -speech the analysis of FDR data can be problematic The cause of accident may be present in the technical and aerodynamic sounds

9. Analysis tradition Auditive analysis • Experienced experts • pilots, preferably with same ratings • ATCOs • Qualitative analysis Problems • Highly sensitive material • Reference samples? • Objective investigation??

10. Database project Arranging a separate test flight is a very expensive way to collect reference samples Database Organized collection of sound samples from • different a/c types and models, e.g. Airbus A320–family, Embraer 170 etc. • same type, but different a/c, e.g. Airbus A320 aircrafts 1-5 • from different procedures, e.g. taxing, take-off, en-route, approach etc.

11. Future work • Negotiations with • different Airline companies (Finnair at the moment) • pilots’ association • pilots’ trade union etc. • Co-operation with AIB • Database can be used in accident investigation • New quantitative analysis method • Funded by Etelä-Savo Regional Fund of the Finnish Cultural Foundation.