The global push to implement a complete strategy to improve aircraft tracking and flight data recorder recovery faces two key hurdles: avoiding a prescriptive approach of piecemeal, country-by-country rules and—in the U.S., at least—a favorable cost-benefit analysis, a U.S. Government Accountability Office (GAO) study found.
The report, prepared for Congress and released in May, explores the technologies from the viewpoint of 21 stakeholders, including the FAA, NTSB, airframers, airlines, avionics makers and satellite service companies.
While the GAO did not issue any recommendations, the feedback it received raises questions about certain aspects of the International Civil Aviation Organization’s (ICAO) preliminary plan. Among the biggest unknowns: whether ICAO’s plan will dovetail with the equipment U.S. carriers already carry that can meet proposed standards, which would simplify global harmonization efforts.
At the conclusion of February’s ICAO High Level Safety Conference, held in response to the disappearance of Malaysia Airlines Flight 370 (MH370) in March 2014, delegates from 120 countries endorsed the concept of a Global Aeronautical Distress and Safety System (GADSS) that features four components: Tracking of all aircraft by airlines every 15 min. during normal operations and every 1 min. if an abnormal event occurs; an independent, tamper-proof distress tracking system to broadcast positions during abnormal events; an automatic deployable flight recorder or a performance-based alternative; and upgrades in search-and-rescue operations. After consultation with members, ICAO plans to formally adopt the GADSS concept in 2016.
The 15-min. tracking plan represents the least important concern for U.S. carriers. The GAO found that most U.S. airlines flying in remote or oceanic areas where tracking is most critical are already equipped with Future Air Navigation Systems (FANS) capability, which is required to use prime North Atlantic intercontinental routes, or the Aircraft Communications Addressing and Reporting System (ACARS). Both systems can be configured to report every 15 min. or more frequently, and FANS, coupled with Automatic Dependent Surveillance-Contract (ADS-C) can automatically report position and other data at higher rates if certain thresholds on attitude or routing are met.
U.S. airlines flying oceanic routes often report their position every 10 min. through ADS-C in order to take advantage of reduced separation from other equipped aircraft, and the FAA already requires frequent position reports through ACARS to an airline’s operational control center. One issue with FANS is that approximately two-thirds of air navigation service providers worldwide do not have the ground systems needed to offer the service, says the GAO.
But U.S. carriers are more critical of ICAO’s call for autonomous, tamper-proof distress tracking systems and deployable flight data recorders (FDR). Issues with tamper-proof systems generally revolve around pilots not being able to remove power from the devices and the possibility for false alarms.
Deployable FDRs, used primarily by military aircraft and helicopters, offer the promise of quick post-crash retrieval through emergency locator transmissions. But several stakeholders expressed concern about the device’s cost—estimated to be $50,000-$60,000 per aircraft—and reliability. One stakeholder told investigators that flight data recovery rates are better for FDRs fixed to the aircraft, based on experience from one particular model. According to accident data for that aircraft from 2004-14, there was 100% flight data recovery for fixed recorders compared to 75% with deployable recorders.
“The causes of those failures included instances in which the recorder did not deploy, was not located or did not have data on the memory card,” the GAO says, adding that investigators would also want to recover the aircraft wreckage regardless of whether the deployable recorder is found.
Longer term, ICAO has suggested that dedicated systems for streaming select FDR data during an emergency would alleviate the need to quickly find the FDR after a crash. The GAO reports that the ability to stream voice data may not be possible with today’s streaming data systems, requiring searchers to find the wreckage anyway to recover the cockpit voice recorder. Along with the price of installing the equipment—perhaps $70,000 per aircraft—the GAO says the data could cost on the order of $5-10 per minute.
“The FAA and other stakeholders told us that most aircraft could gather similar data using existing systems (including ACARS), so adding additional equipment to gather and transmit such information may not have an operational benefit for airlines,” the GAO says.
The GAO notes that the financial ramifications of GADSS implementation will not be fully understood until the standards are set.
“Until the technologies and their associated costs to meet the GADSS are determined, it is unlikely that FAA could conduct an analysis to evaluate the costs and benefits of this long-term aircraft tracking framework,” the GAO says.