The safety record of commercial airplanes is excellent and has improved dramatically over the years. Today, the global safety record is more than 10 times better than it was at the beginning of the jet age.
This success is the result of decades of safety improvements by airplane manufacturers, airlines, airports and regulators such as the Federal Aviation Administration (FAA), all working together. The drive to continue to improve safety continues. Boeing is proud of the part it plays in improving commercial aviation safety.
Safety by design
Boeing engineers design airplanes to both prevent failures and to provide protection in the unlikely event that there is a failure. Boeing designs include multiple levels of redundancy – backups – so that no single failure can cause an accident.
Critical systems are separated by function and space ensuring that the loss of one system will not cause the loss of its backup. A robust and ready network of standby and protective systems is designed and built into every Boeing airplane.
Boeing also designs safety into its airplanes with crews in mind. Boeing flight decks are designed so that pilots are always in command and can override automatic controls.
Advanced instrumentation and airplane monitoring tools, and sensory cues such as audible alarms, lighted indicators and moving throttles, control wheels and rudder pedals, are designed to help the crew know continuously how the airplane is responding.
Testing from design through delivery
Beginning at the design phase, every element of an airplane is examined and evaluated to determine how it performs both separately and in conjunction with other parts and systems. Boeing uses a “building block” testing approach, starting with raw materials and separate parts and subsystems; working up to larger, more complex assemblies and systems; and finally including the entire airplane. Each new airplane that rolls off the line undergoes functional, ground and flight testing before delivery.
Using this building block testing approach, Boeing conducted more than 5,000 hours of laboratory testing of the 787 battery system, including baking the battery to induce overheating, crushing the battery and puncturing a cell with a nail to induce short circuiting.
The airplane’s integrated power system, which includes the batteries, underwent more than 25,000 hours of laboratory testing to demonstrate the interaction of various system elements in normal operations as well as in simulated failures.
At the airplane level, the integrated electrical system underwent more than 10,000 hours of testing under normal operations and simulated conditions, including extreme weather, long and short flight durations, and low and high elevations.
The 787 model completed 5,000 hours of flight testing and an equal amount of test time on the ground, all of which demonstrated that the airplane performs as designed. The 787 successfully completed Boeing’s own program to test and validate the design as well as the most robust certification program ever conducted by the FAA. The 787 electrical system was certified along with the airplane on Aug. 26, 2011.
A global commercial aviation investigation system
The investigation process is triggered by accidents and incidents. Incidents are instances of operational conditions that affect or could affect the safety of the airplane. Recent cases involving 787 batteries are considered incidents.
International investigation protocols define policies, processes, and roles and responsibilities for parties involved in an investigation. In the lead are investigative authorities from the country where the accident or incident occurred. They are the only party allowed to comment on progress, final determination and recommended resolution.
787 battery-related investigations
When a 787 ground incident occurred in January 2013 at Boston’s Logan International Airport, the U.S. National Transportation Safety Board (NTSB) stepped in to lead the investigation. Boeing is assisting at the invitation of the NTSB, and the company’s work is directed by the NTSB investigation team.
Similarly, the diversion of a 787 flight in Japan later the same month because of an in-flight battery incident means the Japanese Transport Safety Board is leading the investigation.
Accidents and incidents are rarely caused by a single failure or action. They usually result from a chain reaction or combination of circumstances. That’s why investigations are usually complex and lengthy.
Investigators identify all the factors that might have been part of a chain. Once the probable cause is determined, investigators can make recommendations designed to prevent recurrence, such as new pilot training, new operating procedures, airplane modifications and the incorporation of new technologies.
Solutions that require changes to airplane design take longer because any design changes must be thoroughly tested, analyzed, validated and recertified. In these cases, regulatory agencies authorize interim changes to ensure fleet safety until that full process is completed.
The two incidents occurring in January 2013 remain under investigation by U.S. and Japanese authorities. Boeing will keep the flying public updated on its role in these investigations.