Go Back  PPRuNe Forums > PPRuNe Worldwide > Australia, New Zealand & the Pacific
Reload this Page >

Cobham RJ near collision with light aircraft

Australia, New Zealand & the Pacific Airline and RPT Rumours & News in Australia, enZed and the Pacific

Cobham RJ near collision with light aircraft

Old 1st Dec 2021, 22:52
  #1 (permalink)  
Thread Starter
 
Join Date: Oct 2014
Location: Harbourside
Posts: 8
Cobham RJ near collision with light aircraft

Another NMAC to highlight the limitations of congested CTAF frequencies and unalerted see and avoid.

Report: Cobham RJ1H at Port Augusta on May 26th 2021, near collision with light aircraft in traffic circuit
By Simon Hradecky, created Tuesday, Nov 30th 2021 07:41Z, last updated Tuesday, Nov 30th 2021 07:41ZA Cobham Aviation Avro RJ-100, registration VH-NJE performing flight NC-788 from Adelaide,SA to Port Augusta,SA (Australia) with 37 passengers and 4 crew, was on approach to Port Augusta's runway 15 via a visual circuit maintaining 1500 feet AGL. The crew announced joining the downwind on CTAF about 5.9nm south of the aerodrome and joined the downwind. While at about mid of the downwind the crew observed a light aircraft passing about 50 feet directly underneath them from right to left. Both aircraft continued for a safe landing on Port Augusta's runway 15.

Australia's ATSB released a generic safety report highlighting this safety message:

This incident highlights one hazard associated with operations at non-controlled aerodromes, and reinforces the importance of pilots being thoroughly familiar with the recommended procedures and the likely traffic mix operating at the aerodrome. It is also a reminder to pilots to make clear and concise radio calls and eliminate unnecessary broadcasts, particularly within the CTAF environment.

Further, this incident serves as a reminder of the risk of confirmation bias during operational decision making. Confirmation bias is defined as the tendency to interpret new information as confirmation of existing hypotheses, and as such is a threat to situational awareness and logosound decision making in the aviation environment. In this occurrence, a company RJ100 on the ground at Port Augusta led the pilot of the S2R to erroneously conclude that the aircraft they heard joining the circuit had landed. While the conclusion drawn by the pilot was not unreasonable, it likely reduced the vigilance of the S2R pilot who reported then turning their attention to other tasks of navigation and communication.

The ATSB SafetyWatch highlights the broad safety concerns that come out of our investigation findings and from the occurrence data reported to us by industry. One of the safety concerns is Communication and self-separation in non-controlled airspace.


The ATSB summarized the serious incident:

On 26 May 2021, a BAE Systems Avro RJ100 (RJ100) aircraft was inbound to Port Augusta, South Australia, conducting a regular public transport service from Adelaide, South Australia, with 37 passengers and 4 crew on board. Also inbound to Port Augusta at about the same time, was an Ayres Corporation S2R-T34 (S2R) agricultural aircraft on a positioning flight from Broken Hill, New South Wales, with the pilot as the sole person on board.

The weather was reported as being generally good and suitable for a visual approach,[1] with a visibility in excess of 10 km, no cloud below 5,000 ft and a southerly wind at approximately 10 kt.

At 1337:06 Central Standard Time,[2] the RJ100 was 30 NM south of Port Augusta Airport at flight level 140,[3] and the crew made their first broadcast on the common traffic advisory frequency (CTAF), stating their intention to join the downwind leg of the runway 15 circuit with an estimated arrival time of 1345.

About 2 minutes later, while 14 NM north-east of the aerodrome and passing 2,500 ft on descent, the pilot of the S2R made their first broadcast on the CTAF advising of the aircraft’s position and estimated arrival time in the circuit area also of 1345.

The crew of the RJ100 reported hearing two radio transmissions simultaneously at this time, rendering both transmissions unreadable, but heard the end of the S2R pilot’s transmission stating ‘…Port Augusta’. In response to this, the RJ100 crew reported repeating their inbound radio call but did not receive a response. The pilot of the S2R did not recall hearing that broadcast from the RJ100 crew.

The crew of the RJ100 and the S2R both reported difficulty in being able to make or receive radio calls due to frequency congestion originating from an aircraft conducting circuit operations at Port Pirie aerodrome, which shared the CTAF.

Shortly after repeating their inbound call, and having not received a response, the crew of the RJ100 observed proximate traffic on the aircraft’s traffic alert and collision avoidance system (TCAS) 8 NM south-east of Port Augusta. The S2R was not equipped with a transponder, and as such was not visible to the crew of the RJ100 on their TCAS traffic display. However, the crew of the RJ100 stated that they believed that the TCAS traffic was the same aircraft that had made the previously unreadable radio transmission ending in ‘…Port Augusta’, and assessed that the aircraft did not pose a conflict to their arrival.

At 1343:18, the RJ100 was 5.9 NM south of the aerodrome at 1,500 ft above ground level (AGL) approaching the downwind leg of the circuit, and the crew broadcast on the CTAF that they were joining downwind for runway 15. At this time, the S2R was 9 NM north-east of the aerodrome. The pilot of the S2R reported hearing the transmission but believed the RJ100 was established on the downwind leg of the circuit, and therefore estimated it would be on the base or final leg of the circuit by the time the S2R reached the circuit area.

The pilot of the S2R planned to overfly the circuit at 1,500 ft AGL, descend on the non-active side of the circuit, and then join the circuit at 1,000 ft AGL for a landing on runway 15.

A short while later, as the S2R approached the circuit area, the pilot observed an RJ100 aircraft parked on the tarmac and concluded that it was the same aircraft that had previously reported joining the downwind leg and thought it must have landed. This was, however, another (company) aircraft that had operated into Port Augusta that day.

At 1345:03, the RJ100 was in a mid-downwind position for runway 15 at 1,500 ft. The S2R was approaching the circuit from the north-east also at approximately 1,500 ft. The captain of the RJ100 reported seeing the S2R from their window on the left side of the aircraft, as it passed from right to left about 50 ft directly below the aircraft.

The crew of the RJ100 expressed surprise on sighting the S2R, and broadcast on the CTAF ‘…did you see us?’ to verify if the other pilot had them in sight prior to the aircraft passing below. In response to this, the pilot of the S2R reported that they saw the aircraft pass behind them and had not been aware of the aircraft before then.

Operational factors

Non-towered aerodromes

The majority of aerodromes within Australia operate without the provision of air traffic control services. These aerodromes rely upon pilots broadcasting their positions and intentions on a CTAF and then implementing separation actions that are agreed directly between the pilots.

To guide pilots in interpreting the Civil Aviation Regulations relating to operations within a CTAF area, the Civil Aviation Safety Authority has promulgated guidance in Civil Aviation Advisory Publications (CAAP) 166-01 Operations in the vicinity of non-controlled aerodromes and 166-1 Pilot’s responsibility for collision avoidance in the vicinity of non-towered (non-controlled) aerodromes. CAAP 166-01 states that aircraft should fly at a circuit height that is based upon their relative performance category.

CAAP 166-01 also states that:

where a pilot is unfamiliar with the aerodrome layout, or when its serviceability, wind direction, wind speed, or circuit direction cannot be ascertained prior to arrival, the overfly procedure should be used.

To mitigate the risk of a potential conflict between two aircraft of differing performance categories, and therefore circuit heights, where one aircraft is planning to overfly the aerodrome, the CAAP recommends that:

At aerodromes with high performance traffic in the circuit, the overfly height should be no lower than 2,000 ft above aerodrome elevation.

In this occurrence, the relative performance of each aircraft would mean that the RJ100 should fly a circuit at 1,500 ft AGL, and the S2R should fly a circuit at 1,000 ft AGL. In which case, the pilot of the S2R should conduct the overfly procedure at 2,000 ft AGL to remain safely above the RJ100’s circuit altitude.

The pilot of the S2R reported being unfamiliar with Port Augusta Airport, and as such elected to overfly the circuit prior to joining – in line with the requirements of CAAP 166-01. Unfortunately, the pilot of the S2R was unfamiliar with the operation of high-performance aircraft and the differing circuit heights stipulated in CAAP 166-01, and erroneously believed that the RJ100 would be conducting their circuit at 1,000 ft AGL. This resulted in the S2R conducting the overfly procedure at 1,500 ft, which was the same height at which the RJ100 was conducting its downwind leg.

Communications

Most non-towered aerodromes use a standard frequency for the CTAF. Some aerodromes that experience higher volumes of traffic, or are located close to other aerodromes, are assigned a discrete frequency. At the time of the occurrence, Port Augusta shared a frequency with the nearby aerodrome of Port Pirie. The crews of the RJ100 and S2R reported that the pilot of an aircraft operating at Port Pirie Aerodrome broadcast their position at each leg of the circuit being flown. This does not conform to the recommended broadcasts contained in CAAP 166-01, or align with its recommendation that

the fundamental principle of operating in the vicinity of a non-controlled aerodrome is to only make the broadcasts necessary to ensure other aircraft are aware of your operation

The excessive and unnecessary transmissions contributed to the crew of the RJ100 being unaware of the S2R’s position, and limited their opportunity to implement satisfactory separation.

Traffic alert and collision avoidance system

The TCAS enhances a pilot’s situation awareness by displaying traffic information regarding the position and altitude of other aircraft operating nearby. For aircraft equipped with a TCAS unit, the system will alert the pilot to aircraft in close proximity through a traffic advisory, and then issue an avoiding action to prevent a collision through a resolution advisory if required. The TCAS system gathers position and altitude data through an aircraft’s transponder output to display and generate traffic information to the pilot of a TCAS-equipped aircraft. In this occurrence, the RJ100 was fitted with an integrated TCAS unit, however the S2R was not fitted with a transponder. This resulted in the crew of the RJ100 not receiving any traffic information or resolution advisories regarding the S2R from the TCAS unit throughout the occurrence.

Safety action

In response to this occurrence, the operator of the RJ100 advised the ATSB that further advice had been disseminated to the company’s pilots regarding operations at non-towered aerodromes. Specifically, pilots had been requested to ensure that positional broadcasts are as accurate as possible and include the provision of ‘early, mid or late’ to best describe the aircraft’s position when broadcasting joining the downwind leg of the circuit. Pilots have also been encouraged to verify their intended circuit altitude in circumstances where any doubt exists as to the awareness of this among other aircraft.

The operator of the S2R advised the ATSB that they have reviewed the relevant CAAP regarding operations at non-towered aerodromes, and ensured that all company pilots are familiar with the possibility of aircraft operating at differing circuit heights depending on their performance category.

Prior to this occurrence, safety concerns around frequency congestion and broadcast interference in the Port Augusta area had been reported to the ATSB through REPCON, the aviation confidential reporting scheme. This report and the ATSB’s comments are available as REPCON AR2020-0066.

Humans are never infallible, and the system continues to let us down. This country's luck will run out.

Wear the Foxhat is offline  
Old 1st Dec 2021, 23:13
  #2 (permalink)  
 
Join Date: Jan 2008
Location: Australia
Posts: 252
It's now about 50 years past the time when common/shared CTAF frequencies were acceptable. There are plenty of frequencies, and congestion/confusion reins supreme on 126.7, and on many shared frequencies.

CASA should immediately start implementing unique CTAF frequencies; leave 126.7 for non-ERSA airfields; and limit shared-airfield frequencies to those fields very close together.

Yes, there will be some confusion amongst those few old pilots who haven't updated their docs or their mind in years. But we have technology - it would cost very little to temporarily install something like a beep-back radio saying "The correct frequency is...".
drpixie is offline  
Old 2nd Dec 2021, 01:57
  #3 (permalink)  
 
Join Date: Oct 2021
Location: Oz
Posts: 71
“This country's luck will run out.”

Yup. Just rolling the dice.
As I have said on another thread its Mickey Mouse Third World. It will take a hull loss for the numpty Regulators to wake up.
The subsequent Royal Commission will be a ripper.
Alt Flieger is offline  
Old 2nd Dec 2021, 03:52
  #4 (permalink)  
 
Join Date: Dec 2005
Location: Aust
Posts: 182
Seems a little strange then that in June CASA changed the YPAG frequency to 126.9 which it now shares with TWO other airports in the area instead of the one (Pt. Pirie) that it did when this incident occurred.

Now we have Whyalla, Pt. Augusta, and Pt. Pirie all on the same frequency which surely makes congestion more likely, not less.
rcoight is offline  
Old 2nd Dec 2021, 06:46
  #5 (permalink)  
 
Join Date: Sep 2015
Location: Australia
Posts: 409
Originally Posted by rcoight View Post
Seems a little strange then that in June CASA changed the YPAG frequency to 126.9 which it now shares with TWO other airports in the area instead of the one (Pt. Pirie) that it did when this incident occurred.

Now we have Whyalla, Pt. Augusta, and Pt. Pirie all on the same frequency which surely makes congestion more likely, not less.
I think YPAG is much quieter now that you don’t have to listen to the constant babble of the scenic flights at Wilpena Pound plus the FTA training traffic at the Riverland and York Peninsula strips on 126.7.
Cloudee is offline  
Old 2nd Dec 2021, 07:52
  #6 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 4,173
The “requirements” of CAAP 166-01?

The differing circuit heights “stipulated” in CAAP 166-01?

Yeah nah. You have to keep resisting the desire turn non-binding advisory material into law, ATSB.

All the ag pilots I know get vertigo above 300’ AGL. I’ve never seen one do a circuit. 2000’ AGL overfly? I suppose there’s a first time for everything...
Lead Balloon is online now  
Old 2nd Dec 2021, 08:02
  #7 (permalink)  
 
Join Date: Dec 2000
Location: Australia
Posts: 1,134
Originally Posted by Lead Balloon View Post
The “requirements” of CAAP 166-01?

The differing circuit heights “stipulated” in CAAP 166-01?

Yeah nah. You have to keep resisting the desire turn non-binding advisory material into law, ATSB.

All the ag pilots I know get vertigo above 300’ AGL. I’ve never seen one do a circuit. 2000’ AGL overfly? I suppose there’s a first time for everything...
At a country aerodrome I once saw an ag acft land immediately behind an RPT on the same runway. When the RPT turned around at the end of the runway to back track they saw the ag acft turning off to a taxiway.

The radio chatter indicated the RPT was - unimpressed - and the aggie couldn't see what the problem was ....
CaptainMidnight is offline  
Old 2nd Dec 2021, 09:35
  #8 (permalink)  
 
Join Date: Jul 2003
Location: these mist covered mountains are a home now for me.
Posts: 1,729
The RJ100 was 5.9 NM south of the aerodrome at 1,500 ft above ground level (AGL) approaching the downwind leg of the circuit, and the crew broadcast on the CTAF that they were joining downwind for runway 15
Six Miles south of the airport is quite a confusing time to call Joining Downwind.
Runaway Gun is offline  
Old 2nd Dec 2021, 09:59
  #9 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 4,173
Yes. It's surprising the report did not also quote the CAAP requirement recommendation that the call be made "Immediately before joining the circuit."

2 minutes before joining doesn't seem to me to be "immediately before".

Still, I reckon frequency congestion is the bigger issue, generally.
Lead Balloon is online now  
Old 2nd Dec 2021, 11:06
  #10 (permalink)  
 
Join Date: Dec 2005
Location: Aust
Posts: 182
Originally Posted by Cloudee View Post
I think YPAG is much quieter now that you don’t have to listen to the constant babble of the scenic flights at Wilpena Pound plus the FTA training traffic at the Riverland and York Peninsula strips on 126.7.
If the report says that part of the problem was frequency congestion due to traffic at Pirie broadcasting at the same time, how does adding Whyalla into the mix help?
rcoight is offline  
Old 2nd Dec 2021, 19:40
  #11 (permalink)  
 
Join Date: Sep 2002
Location: Great South East, tired and retired
Posts: 3,741
2 minutes before joining doesn't seem to me to be "immediately before".
Maybe he saw a gap in the radio Tx and spoke then? Waiting until immediately before can lead to not being able to Tx and being in the crowded circuit without a call. Been there, done that.
Ascend Charlie is online now  
Old 2nd Dec 2021, 22:36
  #12 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 4,173
Valid point, AC.
Lead Balloon is online now  
Old 2nd Dec 2021, 23:37
  #13 (permalink)  
 
Join Date: Dec 2013
Location: Elsewhere
Posts: 519
Originally Posted by Lead Balloon View Post
Yes. It's surprising the report did not also quote the CAAP requirement recommendation that the call be made "Immediately before joining the circuit."

2 minutes before joining doesn't seem to me to be "immediately before".
I guess ‘immediately’ is a relative thing. Personally I’d rather be advised of a potential collision risk a couple of minutes before it happens, than 5 seconds before.

itsnotthatbloodyhard is offline  
Old 3rd Dec 2021, 00:03
  #14 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 4,173
Yaabut...

The 'mind picture' of those hearing a 'joining downwind' call is that around two minutes later an aircraft like an RJ100 is turning base or final. Why else would the recommendation be "immediately before"?

It would have been far better - **wisdom in hindsight alert** - if the call had been '6 miles south joining downwind runway 15 in 2 minutes'.
Lead Balloon is online now  
Old 3rd Dec 2021, 03:08
  #15 (permalink)  
 
Join Date: Jun 2006
Location: Brisbane
Posts: 265
Isn’t the elephant in the room the fact that the ag pilot’s inbound call was blocked, and nobody let him know?

”Station transmitting on Port Augusta CTAF, your transmission was blocked, say again.”
Derfred is offline  
Old 3rd Dec 2021, 20:15
  #16 (permalink)  
When you live....
 
Join Date: Sep 2004
Location: 0.0221 DME Keyboard
Posts: 943
Originally Posted by Derfred View Post
Isn’t the elephant in the room the fact that the ag pilot’s inbound call was blocked, and nobody let him know?

”Station transmitting on Port Augusta CTAF, your transmission was blocked, say again.”
How did anyone know his transmission was blocked?
UnderneathTheRadar is offline  
Old 3rd Dec 2021, 20:59
  #17 (permalink)  
 
Join Date: Nov 2001
Location: Australia/India
Posts: 4,173
Because the pilot of RJ100 heard ‘Port Augusta’ and reasonably (in my view) assumed that was the end of a broadcast relevant to Port Augusta. The pilot consequently made another inbound call on the reasonable (in my view) assumption that whoever had made the ‘blocked’ call would respond or at least understand the RJ100’s location and ETA.
Lead Balloon is online now  

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.