Commercial air transport aircraft will soon be required to be equipped with deployable flight data recorders, or flight tracking equipment, or both. The only question is how soon.
ICAO has set up working groups to investigate the available technologies and make recommendations, and influential organisations like the Flight Safety Foundation have thrown their weight behind the idea. Airbus now says it is preparing to equip its large widebody fleet with deployable flight data and cockpit voice recorder (FDR/CVR) systems, while Boeing has already installed deployable recorders on at least three military fleets, but so far disagrees with its European competitor that the technology is appropriate or safe for commercial transport aircraft.
The June 2009 loss of Air France flight 447 in the South Atlantic led to renewed – and strident – calls for deployable FDRs (DFDRs) with embedded emergency locator transmitters (ELT), because it took two years of costly searching to locate the wreckage of the Airbus A330-200 on the seabed and recover the FDR/cockpit voice recorder (CVR). When recovered, the recorders did, however, yield up their data.
The delay in recovering important AF447 data and the expense of the two-year search to find the seabed wreckage led to the recently-announced Airbus decision to install a deployable FDR/CVR with a locator beacon on future A350s and A380s. Speaking in Washington DC at the US National Transportation Safety Board’s forum on emerging flight data and locator technology, Airbus’ head of security operations Pascal Andrei said that Airbus has been working with suppliers on deployable recorders and technology will be available “very quickly”, while admitting the company has to complete some additional studies.
More recently, when Malaysia Airlines flight MH370 went missing over the Indian Ocean in March, there were concerted calls for universal flight tracking, because the idea that a modern airliner could just go missing and not be found – however rare such an event might be – is deemed unacceptable by an incredulous travelling public.
This point was quickly taken up by ICAO and IATA. The Malaysia Boeing 777-200 has still not been found, and there is no certainty it will be. The aircraft’s estimated position information at the time it would definitely have run out of fuel is very imprecise. This contrasts with the AF447 case where its last transmitted position left a relatively small circle of uncertainty. Also, in the AF447 case, some floating wreckage was quickly found, but in the Malaysia case no trace of anything associated with the missing aircraft has yet been identified.
Under the agreed ICAO framework, contributions by industry through an Aircraft Tracking Task Force (ATTF) coordinated by IATA “will help address the near-term needs for flight tracking”. ICAO Council President Olumuyiwa Benard Aliu explained: “Malaysia Airlines Flight MH370 has been an unprecedented event for aviation and we have responded here in a similarly unprecedented manner. While our flight safety work logically focuses the majority of our energy and resources on accident prevention, everyone in our sector also deeply sympathizes with the families of this lost aircraft’s passengers and crew.”
But the slow Malaysian and international reaction to the MH370 loss indicated a systemic failure of communications that ICAO believes needs a remedy, even if mandatory universal flight tracking and DFDRs are implemented. ICAO commented: “The meeting also recognised the challenges faced by states when coordinating their search and rescue efforts across national and regional areas of responsibility, stressing the usefulness of regularly run practice exercises to identify procedural or operational gaps.”
ICAO has since been calling for states to set up contingency communications systems, and to carry out joint exercises to prove them.
The highly influential Flight Safety Foundation says it believes that a deployable flight data recorder or triggered data transmission should be required “in addition to the standard cockpit voice recorder and flight data recorder already in all transport aircraft”. The DFDR should include an emergency locator transmitter as well, it says, adding: “By using GPS technology, there would be no reason that it wouldn’t be found and retrieved very quickly after an accident or incident.”
DFDRs are not a new idea. The technology for deployables not only exists, it is already in use with some of air forces. As for tracking or surveillance technology for aircraft beyond radar coverage, plenty of alternatives also exist for automatic dependent surveillance-type systems reporting via satellite, but since tracking is not considered essential for air traffic management (ATM) purposes in low-traffic oceanic and wilderness areas, it has not been mandated because of the communication costs involved.
Meanwhile Boeing has installed similar systems on military aircraft, including the F/A-18 fighter and commercial derivatives such as the E-4B airborne command post (747) and P-8A maritime aircraft (737). That experience over more than four decades has made Boeing aware of potential reliability problems, especially with aircraft that lack ejection seats as an activation system for the deployable recorder.
Commercial aircraft must instead rely on sensors that can detect when a crash or mid-air collision is imminent, which can lead to dangerous miscalculations, according to Mark Smith, a Boeing air accident investigator. He cited an example from the mid-1970s of an E-4B inadvertently jettisoning a deployable recorder over downtown Seattle on final approach to Boeing Field. Designing a system that yields as little as one inadvertent deployment in 10 million flights would be “difficult to achieve”, Smith says. There are nearly 55 million commercial flights per year, implying at least five or six inadvertent recorder deployments annually. Smith adds: “I’m not saying deployables are a bad idea, but there’s a balance of benefit and consequence we need to keep in mind.”
New Jersey, USA-based Finmeccanica company RDS Technologies is the manufacturer of this DFDR technology, which it calls DFIRS. It is an integrated FDR and ELT that is standard equipment on the Boeing F/A-18C, D, E, and F model aircraft. Its built-in ELT, says the company, provides immediate alert of a downed aircraft, supporting prompt location of the crash site and the crew and recovery of the flight recorder module. The deployment of the DFIRS is triggered automatically by an impact sensor or through activation of the ejection seat, ejecting the device into the aircraft slipstream where it “flies” away from the aircraft on deployed aerofoils. It is designed to be impact resistant and to float “indefinitely”, says RDS.
Airbus and Boeing have agreed on other areas where flight tracking and data reporting via datalink can be improved. For example, aircraft health monitoring systems can already send updates at pre-selected intervals, such as every 10min or 30min using ACARS (aircraft communications addressing and reporting system). If the aircraft turns off a flight-planned route or exceeds predetermined limits, the reporting updates can be accelerated to once every minute.
Whereas an aircraft tracker is designed only to transmit the aircraft’s position and identification throughout its flight, existing onboard FDR/CVR systems just contain the recordings of the aircraft’s operational, engine and systems data, plus cockpit communication and ambient sound, to help investigators determine what happened in the event of an accident. The position of a crashed aircraft is not provided by a standard FDR, but by separate ELT embedded elsewhere in the aircraft.
Today’s aircraft ELTs are activated by impact-caused deceleration to transmit an emergency signal that search teams can home in on. If the ELTs fail (there are usually two), there is a risk the aircraft and its data/voice recorders will not be found – or not for a long time anyway. ELTs also have limited range, a broadcasting life of about 30 days, and they do not have sufficient power to provide an above-water signal if the wreckage comes to rest on a deep sea-bed.
In its recommendations in the AF447 final accident report, French accident investigation agency BEA recommended the use of deployable FDRs with embedded ELTs so it would never again take so long to find and download a “black box” recorder. A DFDR in the AF447 A330 would have been deployed either on impact with the sea or triggered by other agreed parameters. In any case, it would have been designed to float so its locator signal would have been picked up by search teams.
The last signals from a standard flight tracking system would help rescuers and investigators find an aircraft after an accident even if the aircraft’s ELT failed, but it does not supply aircraft operational and engineering data – only the FDR/CVR does that. There is, however, a hybrid system which can enable position tracking and also transmission of real-time aircraft data via a datalink, like the well-established ACARS can be set up to do. Canada-based Flyht Aerospace Solutions offers such a hybrid system. Under the brand-name FLYHT, the company offers several products and backup services. One of them, called AFIRS UpTime, allows airlines to monitor and manage aircraft operations anywhere in real time. In an emergency, a triggered data-streaming mode marketed as FLYHTStream automatically sends FDR data and position information to designated sites on the ground in real-time.
A serious issue raised by what happened to MH370 is this: whatever system is ultimately chosen, the authorities have to consider whether it should be designed to be tamper-proof. This issue arises because, for unknown reasons the MH370 aircraft’s ACARS and secondary radar transponder stopped transmitting not long after departure, but just before the aircraft turned away from its flight planned route. The most widely-proposed theory for this is that the act of switching off the signals and the diversion from the flight plan was a deliberate action by someone on board. But what ICAO and the industry has to consider is whether the inability of a crew to isolate any piece of electrical equipment is an unacceptable fire risk, especially in the light of the fact that deliberate acts to harm aircraft and their passengers by flying them to their doom are vanishingly rare.
In May 2014, ICAO set up the ATTF to be coordinated by IATA, and in parallel with this, the organisation aims to develop a concept of operations covering how the new tracking data would be shared, with whom, and under what circumstances. It is all very well saying flights must be trackable anywhere, but tracking could be carried out for malign as well as benign reasons.
The Airbus DFDR concept involves deploying one of two FDR/CVR “black boxes” in the event of a mid-air collision or impact with the ground, one embedded and the other deployable. The deployed unit would include a locator beacon, and be designed to float if a crash occurs in water. In the case of the Yemenia crash in 2009 – which involved impact with the sea close to shore while the aircraft was positioning to land at night – a floating locator beacon might have saved lives. One passenger was found alive, but others may potentially have been saved too.
One of the Airbus suppliers at the US National Transport Safety Board forum, Honeywell vice-president of aerospace regulatory affairs Chris Benich, described how a deployable recorder would work. The system first senses the start of a crash sequence and releases the deployable recorder from the aircraft. In a previous patent filing, Airbus described the installation as a lower panel in aft fuselage near the tail cone. If the system lands on water, it is designed to float indefinitely, with a locator beacon alerting search crews of its presence. A purpose-built DFDR also has the potential to address a chronic reliability problem for existing ELTs. Each commercial aircraft is required to carry two, but they often do not survive the crash. Airbus statistics show that ELTs were activated in only 28% of reviewed incidents.
Source: Flight International
