Streaming Flight Data Recorder (FDR) Data via Satellite Khalil Radhi Embry-Riddle Aeronautical University Daytona Beach, Florida Worldwide Online Instructor: Sandy Krigel June 14, 2010

Streaming Flight Data

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Abstract The humble black box of an aircraft that silently keeps recording data about various flight parameters suddenly assumes central importance in the event of an accident. Because they are encased within tough protective shields, the flight data recorders usually withstand the force of the impact and are retrieved by the search parties. On occasions, however, these black boxes go missing and vital clues to the accident are lost with them. Not being able to recover data from the black boxes and understanding the exact circumstances that led to an accident can have serious implications for the safety of aircraft operations, since these same set of circumstances can be repeated in the future. The risk of repeated air disasters could be mitigated if the data from the flight data recorders could be streamed in real time and stored on servers on the ground. The Air France disaster of June 2009 which sunk the plane and all its passengers to the bottom of the ocean has provided a powerful impetus to equip planes with enhanced data streaming capabilities. FDRs with real-time data streaming option could be harbingers of a paradigm shift.

Streaming Flight Data Streaming Flight Data Recorder (FDR) Data via Satellite

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In the aftermath of an aircraft disaster the top priority of search efforts would be to locate the black box or the flight data recorders (FDR), which can hold vital clues about the causes of the accident. However, it usually takes much time and effort to locate the FDR among the widely scattered debris at an accident site and there have been several air disasters over the past couple of decades where FDRs could not be retrieved. Flight accidents happening in the middle of an ocean expanse pose a particular problem in this regard. Just last year, on June 1, 2009, Flight 447 of Air France, en route to Paris from Rio de Janeiro, plunged into the Atlantic Ocean killing all the 228 people on board. Its flight data recorder, as well as the cockpit voice recorder (CVR), could not be recovered despite extensive underwater probing. The commercial airplanes of today are far advanced over those of two or three decades ago, and yet the modus operandi of these two crucial components in an airplane the FDR and CVR has basically remained the same. Both these instruments are passive recording boxes with no live data transmission capabilities. The FDR collects data on over 250 parameters related to various aircraft systems, and the CVR stores cockpit audio including crew conversations of the past couple of hours at best. If the data from FDR and CVR could be transmitted to a server on the ground it would greatly help the investigation process in the event of an accident, whether or not the physical components are recovered. Ordinarily it is believed that pilots are in continuous communication with the ground control. Pilot to ground communications, however, mostly happen via radio signals and there are large swaths of the globe, such as oceans, deserts, and the interior of large forests, which are not covered by radar. When a plane is out of reach for radio signals, the pilots are essentially on their own. Except for brief automated messages that concern the routine operation and maintenance of

Streaming Flight Data an aircraft, all contact with ground is severed for several minutes to hours as the aircraft negotiates the radio blackout zone. These messages are sent via satellite but they are usually not very helpful in understanding the causes and nature of an accident if it occurs. In the case of

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Flight 447, the little that the investigators knew about the accident came from this telemetry data. However, very limited data is transmitted through these intermittent satellite messages that are based on a technology called ACARS Aircraft Communications Addressing and Reporting System. After the last radio message from the Air France Flight 447 crew, in which the pilots reported flying through thunderclouds, 24 ACARS messages were transmitted in all to the control center (Traufetter, 2009). For example, a message, 221002006AUTO FLT AP OFF, indicated that the autopilot was switched off even as the turbulence of tropical thunderstorm continued. Transmitting data by satellite in this manner is expensive and therefore the large volumes of data generated by an FDR cannot be streamed this way. In fact, streaming such massive amounts of data even by radio signals happens to require a very large bandwidth and is therefore an expensive proposition for the airlines. It is generally thought that ACARS simply does not have the bandwidth range to stream down the FDR and CVR data in real time. Flight data recorders are usually recovered by homing in on the weak radio signals they emit at the accident sites. However these instruments have a battery life of only 30 days. The FDR of Flight 447, an Airbus A330-200, would have run out of power after July 2nd and therefore the search for it was officially called off thereafter (Negroni, 2009). This would have been extremely frustrating for both the airlines and aircraft manufacturer to let so many people die without being able to piece together what exactly led to the tragedy. Hypothetical scenarios were extended but airlines and aircraft manufacturers cannot simply

Streaming Flight Data afford to lose a huge plane carrying so many passengers without being able to pin down in

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minute detail what exactly went wrong. Such details which could be possibly obtained only from FDR data would be of critical importance in improving flight safety and preventing future accidents. It would help investigators determine whether the accident is caused by human error or an external event or a mechanical failure in the airplane system or fault in the aircraft or various combinations of these (Kavi, Aborizka, 2001). The Air France disaster, and a subsequent incident involving another Airbus of Yemenia Airlines that killed 152 people in June 2009, starkly highlighted the need to find alternative ways to retrieve critical flight data which generally implies streaming the data in real time. Bandwidth and the costs are the real problem here but there are other complications and technical hurdles too, as those arising from the number of flights operating in an air space at any given time. Real-time streaming of flight data is by and large feasible but it is not practicable because of the sheer volume of data FDRs generate. Nonetheless, in an age when satellite communications seem so commonplace and are used for all kinds of mundane and frivolous purposes, it might appear very strange that airlines are facing major difficulties in having critical data that could save hundreds or even thousands of lives transmitted via satellite. It might even appear scandalous that a highly sophisticated multi-million dollar aircraft such as Airbus A330 on the safety standards of which the lives of thousands of passengers depend is unable to incorporate seemingly simple technologies that ordinary cell phone users have access to. Moreover, some of us may wonder, NASAs space shuttles use continuous streaming of data via satellite so why not commercial jets? The answer is simply that the logistics of using

Streaming Flight Data continuous satellite data transmission in thousands of planes that traverse the skies are different from those of either the space shuttle or of the cell phone.

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L-3 Aviation Recorders, the largest maker of flight data recorders in the world, conducted a study a few years ago and came up with the estimate of $300 million additional annual expenditure for a typical U.S. airline company to transmit FDR data via satellites, and this is after making due concessions for falling prices of satellite data transmission (Lopez, 2009). Such costs are obviously prohibitive for the airline industry which is just trying to survive in times of economic hardship. There should be of course ways to bring down the costs and get around various logistical and technical challenges associated with live streaming of FDR data, and a number of small innovative companies have for several years now been involved in developing practicable ways to do it. The one obvious way to tackle the problem of data overload is by focusing on transmitting FDR data only during emergencies and not at all times. A particularly notable development is a powerful wireless server brought out by Western Avionics called CommuniCube or C3, which is capable of streaming emergency data from FDR and other inputs to the ground. CommuniCube has been available for the past few years and is already widely used in commercial aircraft for various kinds of data transfer, including transmitting emergency medical services (EMS) patient data to a hospital in advance of the patients arrival. The C3 was originally developed to transmit operational and maintenance data just like ACARS, but over the span of a few years it grew capabilities to the point where it could serve as a real-time data streaming FDR by itself if need be, in addition to transmitting all kinds of other relevant data during a possible emergency. In practical terms, while the C3 cannot substitute an

Streaming Flight Data FDR it can supplement it when signs of trouble appear. The C3 can begin to transmit FDR data as soon as the pilot pushes a panic button or it can function in the auto mode EDAT (Emergency Data Automated Transfer) and begin to transmit data as soon as it detects abnormal changes in certain flight parameters (Eturbonews.com, 2009). The C3 is currently installed in a number of commercial airlines, mainly for FOQA

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(Flight Operations Quality Assurance) purposes, but unfortunately Air France Flight 447 did not have one on board. Millions of dollars that were spent in the futile search for Flight 447's FDR could have been saved if the aircraft carried a C3 with it. The C3 can transfer data via satellites or via HF or WiFi. AeroMechanical Services, a Calgary-based Canadian company just as is Western Avionics, designed a robust system for continuous streaming of data from aircraft to ground, called AFIRS (Automated Flight Information Reporting System). AFIRS 220, branded as FLYHT, is the latest version which links onboard GPS and FDR to a ground server using the Iridium global satellite network, routing messages to any number of designed recipients simultaneously. AMS has dealt with the bandwidth problem by efficiently compressing flight data so that it can be transmitted on the available bandwidth. The system is also capable of sending two way voice communications via satellite so that the crew could stay in touch with the ground during radio blackouts. The Iridium satellite network has total coverage of the globe, and as a result the AFIRS data streaming would not face any gaps or interruptions. The AFIRS 220 has also emergency mode data streaming option which could be activated or self-activated when required. The AFIRS system can be of great use for aircraft that go out of radar coverage for protracted periods of time. Dozens of airlines across the globe have shown interest in the AFIRS

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system and have contacted AMS in order to benefit from this new technology which can provide valuable contributions to air safety and efficiency both during normal times and during emergencies. Alternatively, the existing ACARS technology itself can be modified to transmit important flight data during emergencies. The ACARS system could be reprogrammed to turn it into an online black box such as the C3, without necessitating any significant upgrade of technology. When this system is optimized, hundreds of aircraft parameters can be transmitted at speeds as low as four to eight kilobits per second, according to Krishna Kavi, a professor at the University of North Texas in Denton, who first proposed the idea of transmitting FDR data by means of ACARS in 2001. ACARS already plays a versatile role and performs a number of different tasks in an aircraft. For example, the crew can send messages to the ground about possible delays, or the system can notify ground technicians of any minor malfunction in the aircrafts performance so that repairs can be started soon after landing. Lufthansa has used this system to convert some of its intercontinental aircraft into flying weather stations. Incidentally, one of these weather monitoring aircraft flew in the same area where Air France Flight 447 perished, passing just half an hour before it. Nothing unusual in the weather was spotted by the Lufthansa plane, a fact which highlights the suddenness of the onset of the thunderstorm that took down the ill-fated Air France aircraft. The pilots of Flight 447 had apparently very little early warning of the storm that hit them. ACARS could use the Iridium satellite network to dramatically improve flight safety in a number of ways. Iridium offered the FAA the use of its radio frequencies years ago, but

Streaming Flight Data unfortunately the proposal was not taken up in earnest. Things are different now, however. The Air France disaster has been a wakeup call to the entire aircraft industry.

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For years, privacy has been cited as one of the main concerns in transmitting cockpit data via the satellite. In the past, pilots' associations have shown opposition to some proposed measures to enhance communication between the flight and the ground such as installing video cameras in the cockpit. Reportedly, operating crews appear to be very sensitive toward anything that could be considered as possibly posing some threat to their privacy. Advocates of personal rights of pilots have been against transmitting conversations in the cockpit. But this whole issue of crew members privacy is very preposterous. In fact, common sense would dictate that privacy should be deliberately dissociated from cockpit. Pilots should not have any rights to privacy. Pilots are sitting in the cockpit on duty, and not for relaxing and chitchatting as the autopilot takes control of the plane. On the efficiency of their work depends the lives of hundreds of people and much more. If they want to enjoy privacy, they can enjoy all the privacy they want once they are off duty and not responsible for as many lives. People have often suggested encoding the cockpit data being transmitted as a way to guarding the pilots privacy. Encoding may be done if national security interests warrant it, but if it is only for ensuring pilots privacy then it should be purposely avoided. Privacy encourages laxity, complacency, and an atmosphere of jovial relaxation in the cockpit, especially as so many of the functions in a modern commercial jet are automated. On the other hand, if the pilots knew that they could be under surveillance at any time, it would encourage them to be more alert and focused on the task at hand. Some cockpit privacy advocates have gone on record saying things like, People's last words before they die are part of the private sphere and should not be broadcast around

Streaming Flight Data (Traufetter, 2009). Such statements appear ridiculous in the extreme. A majority of flight accidents happen through human error; by omission or commission these pilots are being responsible for the deaths of hundreds of people. It would be extremely frivolous to even talk

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about the privacy and sanctity of their last moments. A dreaded serial killer kills 20 or 30 people typically, whereas through one mistake on his part, a pilot would be killing himself, his colleagues, and hundreds of passengers at one stroke. Any talk about pilots privacy in the cockpit, therefore, is meaningless. And even if the pilots want to utter their last words in privacy, they can whisper those words to themselves away from the reach of audio recording. For years, non-issues like pilots privacy or lack of technology have impeded the implementation of satellite transmission of cockpit data. It was not the lack of technology but the lack of motivation that prevented real-time cockpit data streaming from happening. Today we have many alternative technologies, but way back in 2001 itself Iridium Satellite LLC proposed FAA real-time monitoring of FDR data by using off the shelf technologies, in an affordable manner. More than the technological hurdles, it was the complacency of the aircraft industry that had been responsible for the delay in implementation of real-time data streaming technologies. Although there have been several incidents in the past few decades where the FDRs were not found, such as the South African Airways crash of 1987, France's Air Inter crash of 1992, Austria's Lauda Air crash of 1991, these amount to only a dozen incidents, in all, out of a total of more than 3000 air accidents that occurred since the mid-1970's. And even in the relatively rare instances where the FDRs could not be retrieved, the piecing together of the crash scenario from the wreckage materials, air-traffic control tapes and other evidence usually helped the investigators to come up with adequate explanations of the causes of the accident.

Streaming Flight Data As a result, the motivation for converting the traditional black boxes into real-time data streaming systems was rather low. Over 8,000 aircraft currently use the ACARS technology to

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transmit all kinds of data via satellite linking, and with only a little modification to the software these systems can be used to transmit crucial data during emergencies, and yet this was not done. The ACARS messages from the Flight 447 indicated several malfunctions such as depressurization and electrical failure that quickly built up into a cascade of failures of onboard equipment and flight-control computers, but this data is very meager and cannot provide a clear picture of what exactly led to what (Epstein 2009). If the ACARS system of Flight 447 had been programmed to transmit only a few more vitally important messages during emergencies much of perplexity that surrounds this tragedy could have been cleared. The Air France disaster of 2009 was the first one in so many years to leave essentially no leads to the investigators, and it brought a great deal of public attention to the need of making FDR data more easily accessible. The crash of Air Frances Airbus 330 was almost immediately followed by the disaster of Yemenia Airbus A310 which crashed into the Indian Ocean. The FDR was found in this instance but only after nearly two months of search. An Ethiopian Airlines Boeing 737 that crashed into the Mediterranean Sea earlier in 2009 also gave a great deal of trouble to the investigators in retrieving its black box components. In the wake of a string of incidents where the FDR was either not found or was only found with much difficulty, the deficiencies and antiquated nature of the extant flight digital recording systems became impossible to overlook. Since then European aviation regulators have been expressing keen interest to adopt satellite communications for transmitting critical data during emergencies. At the global aviation summit that took place in Montreal in March 2010, the E.U. representatives made a strong case

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for streaming in-flight data via satellites. They sought the support of representatives from other countries to promote an expanded role for satellite communications in transmitting data from aircraft to ground. The E.U. bid for enhancing the use of data streaming from aircraft marks the first official initiative to make FDR data transfer in real time a reality. A report prepared by an international group of experts and led by a French team concluded that data streaming is feasible and could be cost-effective if only essential data during emergencies was sent. Authorities from the United States NTSB and FAA, from the United Nations ICAO (International Civil Aviation Organization), as well as from the aviation agencies of many other countries are backing the E.U. initiative, although a good number of technical and economic issues need to be addressed before data streaming via satellite could become a regular feature for thousands of operating commercial aircraft. As of now, the idea of supplementing flight data recorders with satellite feeds cannot be dismissed lightly in the aviation circles anymore as it had been done in the past. There is a definite sense of urgency at present. The U.S. and E.U. are currently undertaking a major overhaul of their air-traffic control networking systems. The new systems will rely much more on satellite data links, but this is a long-term effort and will take years to be implemented. Aviation authorities, therefore, are considering much simpler and easily deployable solutions for FDR data streaming. The emphasis is on some real near-term progress, according to Bill Voss, president of the Flight Safety Foundation (Michaels, Pasztor, 2010). The United States has recently, in late March 2010, unveiled more concrete plans for changing the basic paradigm of air traffic control from the current ground-based system to a

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satellite-based system (FAA.gov, 2010). This system, simply dubbed 'NextGen," would be in place by 2018. FDR data streaming would be an integral part of the envisaged transformation of the National Airspace System, and depending upon its technical and economic feasibility it could be one of the first steps toward the larger transformation of the air traffic communications and control systems worldwide and could be operational by 2012.

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References Epstein, K. (2009). Beyond the black box: accidents needn't be so mysterious. Businessweek.com. June 03, 2009. Retrieved June 6, 2010 from http://www.businessweek.com/the_thread/techbeat/archives/2009/06/beyond_the_blac.ht ml ETurboNews.com. (2009). New "black box" will help solve air crash mysteries. ETurboNews.com. Oct 20, 2009. Retrieved June 6, 2010 from http://www.eturbonews.com/12360/new-black-box-will-help-solve-air-crash-mysteries FAA.gov. (2010). What is NextGen? Federal Aviation Administration. April 26, 2010. Retrieved June 6, 2010 from http://www.faa.gov/about/initiatives/nextgen/why_nextgen_matters/what/ Kavi, K.M., Aborizka, M. (2001). Glass-Box: An intelligent flight data recorder and real-time monitoring systems. Proc. of the 39th AIAA Aerospace Sciences Meeting, Reno, NV, Jan. 8-11, 2001. Retrieved June 6, 2010 from http://csrl.unt.edu/~kavi/Research/AIAA-39.pdf Lopez, R. (2009). A better black box. Aviation Today. September 1, 2009. Retrieved June 6, 2010 from http://www.aviationtoday.com/regions/sa/A-Better-Black-Box-MoreNews_34860.html Michaels, D., Pasztor, A. (2010). EU makes push for real-time flight data. The Wall Street Journal Digital Network. Mar 29, 2010. Retrieved June 6, 2010 from http://online.wsj.com/article/SB10001424052702304434404575149512636704730.html Negroni, C. (2009). Airlines study alternatives to jets black boxes. The New York

Streaming Flight Data Times. July 13, 2009. Retrieved June 6, 2010 from http://www.nytimes.com/2009/07/14/business/14blackbox.html?_r=2 Traufetter, G. (2009). Safety Experts Call for Airborne 'Black Box' Data Stream. Spiegel Online. Aug 06, 2009. Retrieved June 6, 2010 from http://www.spiegel.de/international/world/0,1518,629249,00.html

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