Four close calls on Sydney Airport runways in as many weeks have put air traffic management in the spotlight.
Author
- Graham Wild
Aviation Coordinator, Australian Defence Force Academy; UNSW
It’s too early to determine the exact cause of each one. But four ground-safety occurrences at Australia’s busiest airport in a little over three weeks raise an obvious question: how common are occurrences like these, and are they becoming more frequent?
To examine the broader pattern, I analysed Australian Transport Safety Bureau data from 2003 to 2025 for Australian commercial air transport, focusing on runway incursions (the incorrect presence of an aircraft, vehicle or person in a protected runway area) and taxiing collisions or near collisions (an aircraft colliding or nearly colliding with another aircraft, person or object while taxiing).
What happened at Sydney Airport?
The most recent incident occurred just after 8am last Tuesday, when two planes were given permission to use the same runway at the same time. Luckily, one plane stopped when its crew saw the other plane.
A little over a week earlier, on August 9, there were two more incidents in less than three hours.
At 7:20am, a Jetstar Airbus A320 preparing to depart for the Gold Coast encountered an empty Qatar Airways Boeing 777 being towed across a taxiway. Both planes stopped abruptly. One Jetstar cabin crew member sustained a serious injury.
Then, at about 10am, a Virgin Australia Boeing 737 bound for Perth began its take-off sequence on a runway as a Qantas 737 crossed another runway ahead. Both crews reported having received the relevant clearance from air traffic control. The Virgin crew stopped as air traffic control cancelled its take-off clearance.
On July 27, air traffic control cleared a Qantas Boeing 737 to cross a runway while a smaller plane was still landing. Air traffic control detected the issue and alerted both crews, with the 737 stopping after passing the holding point.
Near-collisions have increased significantly
The Australian Transport Safety Bureau investigates and reports on safety incidents involving planes, helicopters, trains and boats. These incidents include those that happen during taxiing, takeoff and landing.
Raw counts of reported occurrences can be misleading because aviation activity has varied substantially, particularly during the COVID pandemic. More flying creates more risk. So I also calculated occurrence rates per million flight hours, for both domestic aviation and all commercial air transport, which includes domestic aviation as well as other forms of aviation such as freight and charter.
For domestic aviation, analysis of the annual data from 2003 to 2025 shows a significant increasing underlying trend in both the number and rate of taxiing collisions or near-collisions. Across the period, the number increased on average by about one additional occurrence every three years. The significant increase in the rate indicates this trend cannot simply be explained by growth in aviation activity.
Across all commercial air transport, taxiing collisions or near-collisions have also increased significantly in number, but not in rate. This suggests increased aviation activity explains at least part of the rise.
Runway incursions show the clearest commercial air transport trend, with significant increases in both their number and rate per million flight hours. Across the period, the number increased on average by about three additional runway incursions every two years.
Neither the count nor rate of domestic runway incursions has increased significantly.
The distinction between number and rate matters. Increasing occurrence counts can reflect greater aviation activity, while an increasing rate indicates the number of occurrences are rising faster than the amount of flying.
Frequency is only half the picture
Aviation safety occurrences are classified as:
- accidents (where serious injury/death or substantial aircraft damage/destruction actually occurred).
- serious incidents (where an accident was narrowly avoided)
- incidents (all other occurrence, which affects or could affect the safety of operation)
This reflects both their consequences and how close they came to a substantially worse outcome.
The four recent Sydney occurrences illustrate this. The July runway incursion and Jetstar/Qatar taxiing near-collision are classified as serious incidents, while the Virgin/Qantas runway incursion is classified as an incident.
The fourth occurrence has not yet appeared in the Australian Transport Safety Bureau’s database. But the bureau has indicated it will also be classified as an incident because there was no immediate risk of collision.
The most striking result from the data is for domestic taxiing collisions and near-collisions. While accidents account for only 0.05% of all domestic aviation events, they account for 2.16% of taxiing events. Three of the 29 domestic aviation accidents recorded since 2003 were taxiing collisions. That’s more than one in ten.
Runway incursions have in general been much less serious. Almost 98% were classified as incidents, with accidents absent from the domestic data and accounting for only 0.10% of commercial air transport runway incursions.
But although most runway incursions are classified as incidents, they can create the conditions for a collision if other safety barriers fail.
Should passengers be concerned?
Four occurrences at one airport in less than a month understandably attract attention. But a cluster does not by itself demonstrate that Sydney Airport has suddenly become unsafe.
The occurrences were operationally different, and the Australian Transport Safety Bureau investigations will determine how each developed and why the available safety barriers did not prevent the conflicts from arising.
Some have suggested air traffic control staffing pressures may be relevant. For example, Civil Air president Scott Nugent said there are not enough air traffic controllers in Australia, that Sydney Airport has relied heavily on overtime, and that some controllers may be working more than 20 additional hours a week.
The Australian Transport Safety Bureau will also examine whether understaffing at Sydney Airport played any role in the recent occurrences.
Whatever the investigations ultimately find about the causes of these recent occurrences, the historical data answer a broader question. What matters is not whether more occurrences are being reported, but whether they are becoming more frequent relative to aviation activity and whether their severity is changing.
For runway incursions involving commercial air transport, the Australian data show a statistically significant increase in both occurrence numbers and the rate per million flight hours. The same is true for domestic taxiing collisions and near-collisions.
That does not establish the cause of the recent Sydney events. It does, however, suggest that the longer-term increase in runway incursions and taxiing collisions and near-collisions warrants attention.
