Published date: 1 May 2017

It’s a world of selfies and rushing to be first to break the news on social media. That’s led to the work of CAA and TAIC investigators being frustrated by people deliberately or inadvertently interfering with aircraft accident scenes.

Interfering with the scene of an accident (as defined by the Civil Aviation Act 1990) is not only dangerous, but against the law. It’s important any physical evidence, such as ground scars, are left undisturbed, for obvious reasons.

There are exceptions to that, such as having to remove survivors – both human and livestock – from wreckage, and protecting the wreckage and any cargo.

Wreckage near the sea can be moved when it’s below the high tide mark or in places where it can be damaged by water. Wreckage can also be moved if it prevents public access through, or aircraft from using, an area when there’s no practical alternative available. Examples are a railway line, major road or an airstrip. If it proves necessary to move the wreckage, photographs of the accident scene should be taken beforehand.

In those cases, the wreckage should be “moved only so far as necessary to ensure its safety; and… be kept in separate distinct areas to indicate from which part in the aircraft it has been taken”. – Part 12 Accidents, Incidents, and Statistics.

It is rare that wreckage would need to be disturbed after survivors are removed.

Investigations

Emergency services are typically the first to respond to an accident. Safety investigators may not arrive until the next day, or even later, if deployed at all.

Once the emergency services’ work is complete, the aircraft involved comes under the jurisdiction of the investigating authority, as outlined by Part 12 of the Civil Aviation Rules, and Part 12A of the Transport Accident Investigation Commission Act 1990.

That means the aircraft owner or operator does not have the right to access the accident site without prior authorization of the investigator in charge.

Even when a safety investigator is not sent to an accident site, owners or operators need to gain clearance from the CAA before the wreckage is moved.

Why so strict?

There are three main reasons for the above rulings.

Firstly, accident sites are inherently dangerous. Many aircraft are now being built from carbon fibre or similar products, and can create a significant hazard if there’s a post-impact fire.

Burned carbon fibre can produce airborne synthetic particles, similar to asbestos, and the smoke created by any carbon fibre-based fire is believed to be dangerous if inhaled.

Safety investigators always perform a full risk assessment before deploying to an accident scene, and again when arriving, to protect themselves against any possible hazards at the crash site. That allows them to decide on the need for any personal protective equipment needed to carry out their investigation.

“There’s no point putting yourself in a position that you’re going to need to be rescued from,” says CAA Safety Investigator, Matt Harris. “Accident sites are also known to contain pathogenic substances, which can cause disease. Potentially explosive devices such as oxygen bottles, highpressure tyres and ballistic parachutes could also be present.”

Ballistic parachutes, which are found on some microlight and certified aircraft, are particularly dangerous. They can be deployed by pilots in an emergency via a rocket that accelerates to more than 200 kph in the first tenth of a second after ignition, and they can be a serious threat to emergency personnel.

“A badly damaged aircraft may have already placed the activating cables of the ballistic parachute into a stretched state which can make an accidental detonation more likely,” says CAA Safety Investigator, Dan Foley.

“Those cables need to be dealt with by trained personnel who carry specialist equipment to make the ballistic parachute safe.”

Secondly, it’s important to protect the sanctity of the accident site. Safety investigators learn about accidents from both the wreckage and the ‘witness marks’ or scars on the ground.

“Scars like propeller strike marks, burned areas, or areas damaged by fuel obviously help the safety investigators determine what happened,” says Matt Harris.

“That job is made more difficult if those marks are damaged by vehicles having been driven across the accident site, or by the footprints of casual observers.

“Likewise, changing the position of the wreckage mars the safety investigators’ ability to determine the sequence of events during the accident.”

The third reason for restricting access to the site is to assist the co-ordination of any necessary rescue.

All accidents should be reported to the CAA on 0508 ACCIDENT (0508 222 433). Those calls are answered by the Rescue Coordination Centre (RCC) which organises any rescue.

They are seeing potentially hazardous situations develop when local companies try to arrange their own ‘save’.

In the last 12 months several helicopter companies have responded to a Proprietary Tracking System (PTS) signal from their own aircraft and have attempted a company rescue at the same time the RCC has responded to the Emergency Location Transmitter signal. That has meant increased air traffic at the accident site, as the RCC helicopters and the company aircraft occupy the same airspace, increasing the hazard level for everyone.

Private companies must, on receiving a PTS signal, immediately contact the CAA (phone 0508 ACCIDENT or 0508 222 433) and then liaise with the regulator as to how best to respond.

So, in short, unless there are people or animals in dire need of help, leave accident sites alone – for your own safety, and for the validity of the accident investigation to come.

Further reading

Read the CAA's Good Aviation Practice (GAP) booklets on: