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Lockhart air crash highlights GPS landing approach flaws

3 September 2007
CONTACT: Peter Carter on 3210 3409 or 0422 445 599

Carter Capner Law has called on federal authorities to act rapidly to improve GPS landing facilities for rural airports like Lockhart River, in North Queensland where one of the nation's worst air disasters occurred in May 2005.

The accident was investigated by the Australian Transport Safety Bureau (ATSB) and the state Coroner. They found that the aircraft slammed into a mountain peak on descent to land in the Iron Range peaks while on a GPS instrument approach under the Instrument Flight Rules (IFR), conducted under Instrument Flight Rules.

It was flying too low in that part of the landing because of pilot error in "situational awareness".

Peter Carter* of Brisbane law firm Carter Capner Law has been campaigning since 2005 for greater safety in GPS landing systems at country airports and says government authorities must act more quickly to rectify the problem.

"Hundreds of GPS guided approaches are conducted by pilots in Australia every day often in non-visual and poor weather conditions."

"The greatest increase in safety will come from augmenting GPS with vertical accuracy obtained from a ground based or other system. Augmentation will mean pilots at rural and remote airports will have the same level of safety available to them as large passenger aircraft at capital city airports."

"This is a clear area of federal responsibility. It's also an infrastructure issue. It's time for urgency and commitment from the cashed up federal government to significantly increase safety for air passengers in rural and remote locations."

"Situational Awareness" errors are common for GPS approaches because of high cockpit workload, inconsistent approach design and poor charting of the descent path. These factors - all recognised by the ATSB - combine to create a situation where the pilot believes they are further along the approach than is the case and therefore descend below the safe level for that part of the landing."

"Pilots are trained to avoid this confusion but government bodies must act with greater urgency to remove the underlying dangers."

Some approaches may also have to be re-designed and landing charts need to be much clearer.

Carter Capner Law has established an online forum on its website www.cartercapner.com.au to petition the deputy prime minister and transport minister Mark Vaile to act with more urgency and commit to an early introduction of the safety measures.

One advantage of GPS approach is that the pilot can descend to a lower ‘minima' before having to make the decision to land or abort and allow additional options for pilots at country aerodromes that have until recently only permitted NDB approaches.

However as the Lockhart tragedy shows, the rapid implementation of GPS has brought with it a new set of issues that now need urgent attention.

"Air Services Australia has tested a Ground Based Regional Augmentation System (GRAS) and its now time for this or one like it to be urgently implemented."

See - http://www.airservices.gov.au/pilotcentre/projects/gnss/gnss_gras_ion2002_paper.pdf also http://www.casa.gov.au/newrules/airspace/apv.htm

En-route GPS navigation for Instrument Flight Rules has been allowed since 1994. It has been available for approaches progressively since around 1999.

The question for government is: "Do we want passengers in rural and remote communities to have the same level of air safety as passengers in major cities?"

Rural and remote Australia can have the same landing safety through GPS approaches but only after the implementation of an augmentation system that provides the necessary vertical accuracy.

Lockhart River is a coastal airstrip in low lying terrain. The airstrip was built long before the application of GPS for aircraft landings. It was positioned to allow safe manoeuvring in the immediate vicinity of the aerodrome.

GPS approaches on the other hand generally require descent and approach along an imaginary extended runway centreline extending for about 30 kms from the airport - in this case over very hazardous terrain.

Lockhart River has two approved GPS approaches, the other one being from the opposite direction (south east over water). The south east approach has far less hazard than that from the north west.

"The hazardous terrain adjacent to this particular approach (from the North West) leave aircraft with little margin for error."

The mandatory carriage of Enhanced Ground Proximity Warning Systems from 1 July 2005 increases the safety of commercial aircraft but this is not an approach guidance device and should be seen as a substitute for a precision landing system for rural and remote Australia that can be achieved by GPS vertical augmentation.

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