The subject of aircraft crashes has unfortunately dominated the media headlines at numerous points over the past couple of years, ranging from malicious attacks, such as the plane shot down over Ukraine in July 2014, to still somewhat unresolved incidents, in particular the missing Malaysia MH370 flight that disappeared in the ocean in March that same year.
As one would expect, the investigation that ensues is often gruelling, time-consuming and expensive, requiring the expertise from a variety of fields and often collaboration between countries in accordance with International Civil Aviation Organization guidelines. The investigation of any incident scene, whether criminal, accidental or natural, will be accompanied by its own set of difficulties and problems. The forensic investigation of a plane crash is certainly no exception.
The discovery of an incident involving an aircraft typically comes to light when air traffic control loses communication with the plane, particularly if the pilots had previously made a distress call. The exact location of the crash site may or may not be immediately obvious. Either way, a number of teams will be instantly gathered to begin the investigation, with the earlier hours of the incident being the most crucial.
As much information about the aircraft will be gathered as possible, particularly pertaining to its maintenance history and if there had been any signs of a potential fault, as well as details of the crew. Weather information will be collected and scrutinised for any possible occurrences that may have placed the aircraft in difficulty. If there were any witnesses to the incident, such as people in the area in which the plane crashed, they may be able to provide beneficial information regarding how the plane looked prior to crashing.
The investigation of the scene itself will involve a tremendous amount of documentation, as with any crime or accident scene, though made immensely more difficult by the likely sheer size of the area under examination. Examination of the wreckage itself may, in theory, aid in establishing the cause of an aircraft incident, such as through examination of a faulty component or the discovery of debris that would suggest a malicious attack. For instance, in the investigation of the shot-down MH17 plane, there was evidence on the outside of the aircraft indicating something trying to get into the plane (in this case the projectile used to destroy it), as oppose to anything originating inside the aircraft. Unfortunately the nature of such incidents are often so catastrophic that even locating such remains are a challenge, as more often than not the debris is strewn over a vast area. Even if components are retrieved, they may have been destroyed by the crash or fire, reducing their value as evidence.
The ease of the investigation of the wreckage and recovery of bodies is largely determined by the site of the crash. When an incident occurs at sea, simply locating the wreckage is the first greatest challenge, and in many cases the plane and thus the people on board are never found. If the wreckage is located, the process of recovering victims and airplane components from the bottom of the ocean is by no means an easy task. This can often be a dangerous process involving highly-skilled divers and specialist equipment, such as inflatable balloons which can be attached to pieces of the aircraft to draw them to the surface for collection.
Should the aircraft strike land, depending on the nature of the crash the wreckage will most likely to scattered across a vast area, making simply identifying and controlling the entire incident scene a great difficulty, let alone effectively investigating it. In the case of the March 2015 Germanwings crash, the incident occurred in the Alps, a mountainous area making scene investigation especially troublesome and dangerous for those involved.
Aviation incidents can occur over any country, which in itself can be problematic in terms of managing the investigation. As in the case of the aircraft shot down over Ukraine in 2014, pieces of the wreckage remained in dangerous areas riddled with war and fighting. These factors can make the vital immediate access to the crash site difficult if not impossible, greatly hindering an investigation. There may be further complications brought about by explosions and fires caused when the aircraft crashes, making accessing the wreckage more difficult as well as potentially compromising already damaged evidence.
When an aviation incident takes place, one of the primary goals of investigators is finding a device known as the black box (though these are actually bright orange in colour). Modern aircraft are now equipped with a number of data recording devices, well-built components designed to record as much data as possible relevant to the aircraft prior to and during the incident and ideally survive crashes and fires. The black box is a small device generally bolted to the aircraft’s tail so as to prevent severe damage in the event of a head-on crash.
These devices are also equipped with an underwater locator beacon, which is activated if the recorder comes into contact with water. This allows investigators to detect ‘pings’ emitted by the device so that the black box can be located. However the device can of course only function for a limited amount of time, typically for around 30 days before battery life is exhausted, so investigators are working against the clock to locate this vital piece of equipment.
The flight data recorder is a device used to record certain operating parameters from the aircraft’s system, the examination of which may be able to indicate if there were any major faults with the aircraft. This can record a range of details including altitude, time, direction, and airspeed, as well as the movement of certain aircraft components, auto-pilot details and fuel levels. The cockpit voice recorder is a unit which typically records sound from microphones worn by the pilot and the co-pilot as well as from the cockpit area. If this device can be recovered intact (or at least intact enough to retrieve data files), documentation of what was audibly occurring in the cockpit prior to and during the incident can be invaluable, particularly if the pilots were unable to communication with air traffic control at the time.
Looking at the catastrophic scenes caused by some aircraft crashes, it is of no surprise that identification of passengers and crew can be an difficult task. Locating the bodies of victims can be a gruelling enough mission, particularly if the incident occurred at sea or over a poorly-accessible area, such as the recent incident over the Alps. When victims are located, the bodies may be damaged beyond recognition by the crash itself, fire, water, or even decomposition if recovery of bodies was delayed. In these instances specialised forensic experts may be required to carry out DNA analysis or examination of dental records, guided by the details known about the victims from flight manifests and the assistance of family members.
Despite a number of recent high-profile plane crashes, aviation remains one of the safest forms of transport, in part down to the strict operating and safety procedures adhered to, many of which were developed following aviation incidents and investigations. If investigators can at least in part deduce what happened to cause an incident, steps can be taken to prevent reoccurrence and make flying safer.
Anthiniotis, N et al. Scientific analysis methods applied to an investigation of an aircraft accident. Eng Fail Anal. 17 (2010), pp 83-91.
BBC News. Malaysia plane; Why black boxes can’t always provide the answers. [online] Available: http://www.bbc.co.uk/news/magazine-26721975
Robson Forensic. Airplane Accident Investigations. [online] Available: http://www.robsonforensic.com/practice-areas/airplane-accident-investigation-expert