Arrival Controller: “AK3, break-off approach now. I say again, break-off approach now, climb to ….”
This occurrence was related to me by my colleague and this was what happened ……
The designated runway for all landings is 17L. In this situation, AK3 was re-assigned to land on runway 17R at about 60nm out and pilot acknowledged the change in runway and read-back correctly.
Due to weather, AK3 had requested to descend to 1500 feet and a short approach to intercept the localiser at waypoint Ubun (about 4.5 nm finals, runway 17L). Arrival Controller informed the Tower that AK3 will be for a short approach for runway 17R. AK3 was given descent to 1500 feet and radar vectors were provided for a short approach for runway 17R.
When AK3 crossed localizer path for runway 17R, the Arrival Controller immediately instructed AK3 to turn right for runway 17R and the pilot acknowledged the clearance with ‘roger’.
Moments later, the Arrival Controller noticed that AK3 did not execute the turn to the right as instructed but was established on short finals runway 17L. As time was critical, coordination with the tower could not be effected, the arrival controller made a quick assessment of the vicinity to ensure that there were no other conflicting traffic, immediately instructed AK3 to break-off the approach.
Conclusion and Lesson Learnt
It was a good practice that there was a prior coordination effected for a short approach when the pilot requested. This prepares the tower to expect the traffic to contact them only on short finals.
When there is a change in the landing runway, it is also a usual practice for the arrival controller to coordinate and get the concurrence from the tower before re-assigning it to the flight.
In this occurrence, to the arrival controller, AK3 was established on the wrong runway and as AK3 was on short finals, it was too late to effect any coordination with tower. Since the required coordination could not be effected, it was a good decision made to instruct AK3 to break-off approach on runway 17L as any uncoordinated actions may pose a threat to the safety of any flight and it is undesirable.
2. Read-backs and Hear-backs / Mind Set / Perception
In this occurrence, both the pilots and controllers have failed to listen diligently. Perhaps, the pilots’ attention were diverted as they were too engrossed in getting round the weather that they did not realise the series of instructions issued by ATC were in conflict with what they had in mind or planned. Controller, on the other hand, in trying to be helpful, had also failed to detect the discrepancies along the way.
2.1 The pilot perhaps did not click that he had acknowledged and read-back the changed in runway to 17R at 60nm out.
2.2 The Arrival Controller had failed to detect and query AK3 when they requested to track to Ubun, a waypoint approximately 4.5 nm finals, runway 17L.
2.3 The pilot had failed to realise that when instruction to track to Ubun was issued, the controller had mentioned runway 17R. It was a conflicting instruction as Ubun was a waypoint on runway 17L and not runway 17R. Perhaps, the pilots were anticipating and waiting for the controller’s instruction to execute the turn to intercept the localiser and selectively listened to what he wanted only.
2.4 The Arrival controller did not realise if AK3 had read-back the instruction correctly. He already had in mind what he expected to hear and therefore did not pay careful attention to the pilot’s read-back, resulting in the error and the subsequent corrective actions.
As a highly skilled arrival controller, he should not have provided radar vectors for an ILS approach to an aircraft for a 4 nm finals. He should be very conversant that any aircraft on an ILS approach would require 2 nm of level flight. By vectoring an aircraft for a 4 nm short finals may contribute to an unstable approach for the flight. In my opinion, if an aircraft request for a 1500 feet short approach to avoid weather, it would be beneficial to counter propose a visual approach. This would allow the pilot “free-play” to circumnavigate the weather and it will be safer as the pilots would know what to do – the correct speed, the terrain around and the right altitude they should be at.
From this occurrence, I would say that the break-off approach for AK3 was the result of a series of undetected errors by both the pilots and ATC. The main source of error was in the human-human interfaces. Both parties had their mind set and assumed that each being professional will do no wrong. There is a saying “it is only human to err” and one of the principles of Human Error is “Everyone makes mistakes”.
Controllers and pilots must be aware and always bear in mind that those Read-backs and Hear-backs are of paramount importance to ensure a safe flight. Do not have a mind set, do not assume, and do not get distracted. We must always listen attentively.
According to ICAO Annex 10 Volume II:
Read-back is defined as a procedure whereby the receiving station repeats a received message or an appropriate part thereof back to the transmitting station so as to obtain confirmation of correct reception.
An uncorrected erroneous read-back (known as hear-back error) may lead to a deviation from the intended clearance and may not be detected until the controller observes the deviation.