Additionally, air traffic control and airline operation centers may be unable  to determine an aircraft’s location if communications equipment onboard  the plane is damaged, malfunctioning, or has been manually turned off. According to the  Australian Transport Safety Bureau, the agency leading the search for the  plane, MH370’s flight path includes three distinct sections:  1.  an initial stage after takeoff in which the aircraft was under secondary  radar, the transponder was operational, and ACARS messages were  being transmitted;  2.  a second stage in which onboard communications equipment were no  longer working and the plane was only being tracked by military radar;  and  3.  a final stage in which the only available information on the flight’s path  comes from satellite communications log data. Several technologies  that are already on board most domestic aircraft can be used to meet this  standard, although airlines would face some costs to equip if they do not  already have those systems or satellite communications equipment. Most Long-Haul Aircraft Are Equipped with Technologies That Can Transmit Location Information, but More Frequent Position Reporting Can Add Costs to Airlines, and Some Challenges Remain

In the aftermath of the MH370 tragedy, the international aviation  community has undertaken a number of efforts to improve global aircraft  tracking capabilities. The Task Force developed a  set of voluntary performance standards to establish a baseline aircraft   The  tracking capability for all commercial passenger aircraft worldwide.key aircraft tracking performance standards proposed by the Task Force  include:
Position reporting every 15 minutes, with capability to increase the  reporting rate in response to an emergency. This concept of operations is discussed further  below. To help mitigate these costs and enhance tracking capabilities in the near  term, aviation stakeholders have offered a number of proposals to  enhance flight tracking. ICAO’s Long-Term Framework for Aircraft Tracking during All Flight Phases Proposes Tamper- Proof Autonomous Distress Tracking, but Poses Several Implementation Challenges

In parallel with the Aircraft Tracking Task Force, an ICAO-led Ad-Hoc  Working Group on Flight Tracking developed a long-term framework— called the Global Aeronautical Distress and Safety System (GADSS)—to  ensure that accurate information about the aircraft’s location is known  during the sequence of events before and after an accident. This framework is designed to  maintain an up-to-date record of aircraft progress and, in the case of a  forced landing, the location of survivors, the aircraft, and the flight  recorders.Force recommendations on tracking aircraft, but goes further, as  described below. assessment of the shortcomings in coordination and information sharing  between air navigation service providers and search and rescue  authorities is needed. Improvements to Flight Data Recovery Are Starting with Extended Beacons, While Other Proposals May Impose Significant Costs, according to Stakeholders

In response to recent aviation accidents, government, international  organizations, and industry have been developing proposals to enhance  flight recorder recovery in oceanic regions. Actions Under Way to Extend Battery Life and Introduce Low Frequency Devices Are Intended to Enhance Flight Recorder Recovery in the Near Term

To help address challenges in locating flight recorders and aircraft  wreckage in oceanic areas, FAA and other international aviation  authorities have taken actions recommended by the French BEA  investigating the AF447 accident to enhance ULBs. ICAO and NTSB Have Proposed Flight Data Recovery without Underwater Retrieval, Though Some Stakeholders Identified Concerns for the Commercial Fleet

In addition to enhancing the ULBs to help locate the recorders  underwater, governments, international organizations, and industry have  been looking at additional changes to improve flight data recovery in  oceanic regions, one prescribing a specific technology and another using  a performance-based approach. While these technologies are designed to improve flight data recovery,  some aviation stakeholders had concerns with installing either of these  technologies on the commercial fleet. Infrequency of accidents and success of fixed recorder recovery:  One avionics manufacturer and two U.S. domestic airlines that we  spoke with questioned the need for deployable recorders given the  safety concerns discussed above and the infrequency of aviation  accidents. Industry stakeholders cited various potential benefits of triggered  transmissions of flight data. Provides data when physical FDR cannot be recovered:  Streaming FDR data allows for post-flight analysis in instances where  the physical FDR or its data cannot be easily recovered, including  cases where a deployable FDR may not be recovered. Concluding Observations

In response to the AF447 and MH370 disasters, the international aviation  community is considering short- and long-term steps to improve aircraft  tracking and flight data recovery with the goal of enhancing accident  investigation and aviation safety. Numerous technologies—including  communications systems onboard most commercial aircraft today, flight  recorders that deploy from aircraft, devices capable of streaming flight  recorder data in real time, and global satellite surveillance systems under  development—have the potential to enhance aircraft tracking and  expedite flight data recovery in the event of an oceanic accident, and  industry continues to develop solutions for these tasks. Agency Comments

We provided a draft of this report to DOT and NTSB for review and  comment. Both DOT and NTSB provided technical comments that we  incorporated as appropriate.
Why GAO Did This Study

The AF447 and MH370 disasters have raised questions about why authorities have been unable to locate passenger aircraft. In response to these aviation accidents, government accident investigators, international organizations, and industry have offered proposals that aim to enhance oceanic flight tracking and flight data recovery on a global scale. Given the implications for the U.S. commercial fleet, it is essential that the Congress understand the strengths and weaknesses of these proposals.
GAO was asked to review efforts to enhance aircraft tracking and flight data recovery. This report describes (1) the challenges in tracking aircraft and recovering flight data highlighted by recent commercial aviation accidents over oceanic regions; (2) government and industry proposals to enhance aircraft tracking, and how aviation stakeholders view their strengths and weaknesses; and (3) government and industry proposals to enhance the recovery of flight data, and how aviation stakeholders view the proposals' strengths and weaknesses. GAO reviewed reports by government accident investigators and others, and technology presentations by avionics manufacturers, including current cost data, which was not available in all cases. GAO also interviewed 21 aviation stakeholders, including FAA, the National Transportation Safety Board, and industry, selected based on their expertise in aviation technology and flight operations. FAA and NTSB provided technical comments on a draft of this report, which were incorporated as appropriate.

What GAO Found

The crash of Air France Flight 447 (AF447) off the coast of Brazil in June 2009 and the disappearance of Malaysia Airlines Flight 370 (MH370) in the southern Indian Ocean in March 2014 highlight several challenges authorities may face in locating aircraft in distress and recovering flight recorders. First, oceanic surveillance is limited, and an aircraft's position may not be precisely known. For example, MH370 continued to fly for several hours outside of radar coverage after onboard communications equipment were no longer working, according to investigators. Additionally, communication and coordination between air traffic control centers in oceanic regions pose challenges. Finally, these accidents show that investigators may have difficulty locating and recovering flight recorders, which are used to determine accident causes, because of the ocean's depth and terrain. For instance, locating AF447's flight recorders took 2 years at a cost of approximately $40 million.
Proposals to enhance aircraft tracking: Following the disappearance of MH370, the international aviation community developed voluntary performance standards to establish a near-term aircraft tracking capability using existing technologies and a long-term comprehensive aircraft tracking concept of operations.
Near-term voluntary aircraft tracking performance standards : An industry task force called for automatic position reporting to airlines every 15 minutes and faster reporting when triggers, such as an unusual change in altitude, are met. According to stakeholders, existing technologies can meet this standard, and many domestic long-haul aircraft are equipped to do so, although some additional ground infrastructure may be needed. However, some airlines may face costs to equip aircraft with these technologies. In the longer term, technologies like satellite-based surveillance may provide global aircraft tracking.
Long-term global aeronautical distress system : The International Civil Aviation Organization has proposed a long-term framework, which is designed to ensure an up-to-date record of aircraft progress and, in the case of emergency, the location of survivors, the aircraft, and its flight recorders. Stakeholders noted that the new framework begins to address the need for improved coordination and information sharing. One component is a tamper-proof distress tracking system, which is not yet available.
Proposals to enhance flight data recovery: Low-cost actions are planned to increase the battery life of the underwater locator beacon—which emits a “ping” to help locate the flight recorders—from 30 to 90 days. In the longer term, two proposals seek to enable flight data recovery without underwater retrieval; however, neither would eliminate investigators' need to recover the wreckage itself or eliminate all search and recovery costs.
Automatic deployable recorders : Designed to separate automatically before a crash and float, deployable recorders may be easier to recover. However, stakeholders are divided on equipping the commercial fleet. Some raised concerns that safety testing is needed and that equipage costs are high and potentially unnecessary given the rarity of oceanic accidents.
Triggered transmission of flight data : Transmitting data automatically from the aircraft during emergencies would allow for some post-flight analysis when the flight recorders cannot be easily recovered. However, some stakeholders raised feasibility and data protection concerns.