Oct 14th 2024 : A Saudi Arabian Airlines Boeing 777-300 operating a scheduled international passenger flight from Riyadh to Islamabad landed on the wrong runway at Islamabad International Airport, prompting a serious incident investigation by Pakistan’s Bureau of Aircraft Safety Investigation (BASI).
The aircraft, registration HZ-AK21, was performing flight SV-724 with 399 passengers and 18 crew on board. Although the flight was cleared to land on runway 10R at Islamabad, the aircraft instead touched down on the parallel runway 10L and rolled out without further incident. No injuries or damage were reported.
Investigation Outcome
BASI has released its final report, concluding that the probable cause of the serious incident was the flight crew’s incorrect interpretation of, and insufficient adherence to, air traffic control (ATC) instructions, which resulted in a landing on the wrong runway.
The investigation also identified multiple contributory factors involving both flight crew performance and air traffic control monitoring, which together removed several layers of safety defense.
Flight and ATC Communications
According to BASI, flight SV-724 departed King Khalid International Airport in Riyadh at 23:27 UTC and proceeded normally toward Islamabad. During descent and approach, the crew was repeatedly advised by Islamabad Area Control and Approach Control to expect an ILS Z approach to runway 10R.
However, throughout multiple ATC exchanges, the crew’s read-backs were consistently incomplete. They frequently omitted the runway side designator (“Left” or “Right”) and failed to mention the approach type, instead responding mainly with waypoint routing such as SUMEB and IS416. Despite these omissions, controllers did not consistently challenge or correct the incomplete read-backs.
After landing, the crew contacted Islamabad Tower and stated that they believed they had been cleared for an RNP approach to runway 10L, rather than the cleared ILS Z approach to runway 10R.
Crew Performance and CRM Issues
BASI identified a significant Crew Resource Management (CRM) failure. Neither pilot adequately cross-checked the full ATC clearances, nor did either challenge the repeated omissions or apparent runway ambiguity. The report highlights that this mutual lack of monitoring removed critical safeguards intended to prevent errors such as wrong-runway landings.
Investigators also cited expectation bias, noting that the crew appeared highly focused on route sequencing and filtered out key information related to runway assignment and approach type.
During the final landing clearance, the Tower Controller cleared the aircraft to land on runway 10R. The pilot’s read-back—“Runway 10…”—was hesitant and omitted the left/right designator. BASI interpreted this hesitation as a possible indication that the crew recognized a misalignment but chose not to question the clearance.
Critically, the crew did not initiate a go-around, despite ambiguity regarding runway alignment. BASI emphasized that standard CRM procedures require a go-around whenever there is doubt about runway identification or clearance during final approach. By continuing to land, the crew bypassed a primary safety barrier that could have prevented the incident.
Air Traffic Control Factors
The investigation identified several shortcomings across different ATC units:
Area Control (Islamabad ACC)
Controllers repeated full clearances after initial incomplete read-backs but did not ensure correct read-back on subsequent transmissions. Emphasis on waypoint routing allowed the runway and approach details to remain unconfirmed.
Approach Control
Approach controllers reissued the ILS Z runway 10R clearance but accepted partial read-backs without insisting on confirmation of critical elements. They also failed to detect the aircraft’s lateral deviation toward runway 10L, despite responsibilities to monitor final approach alignment.
Tower Control
The Tower Controller issued a correct landing clearance for runway 10R but accepted an ambiguous read-back and did not challenge the omission of the runway side designator. Even when the aircraft was observed aligning with the wrong runway, a go-around instruction was not issued, allowing the landing to continue.
Organizational Factors
BASI also highlighted organizational issues within Pakistan’s aviation system. In particular, the dual assignment of supervisory and operational roles to the same controller increased workload and reduced independent oversight. This environment made it more likely that procedural lapses—such as incomplete read-backs and missed misalignment cues—would go uncorrected.
The report further noted that existing civil aviation safety guidance explicitly requires ATC to advise a missed approach when aircraft identification or position is in doubt during final approach. In this case, hesitation to issue a go-around reflected deficiencies in decision-making confidence and procedural compliance.
Weather Not a Factor
Weather conditions at Islamabad were benign and played no role in the incident. Visibility was good, winds were light, and there were no cloud or ceiling limitations. BASI concluded that environmental conditions posed no operational or safety concerns.
Conclusion
BASI concluded that the wrong-runway landing was the result of compounded human and procedural failures, involving incomplete ATC read-backs, insufficient monitoring by both flight crew and controllers, and missed opportunities to intervene during the approach. The incident underscores the importance of strict read-back/hear-back discipline, assertive CRM practices, and proactive ATC intervention—particularly the timely use of go-arounds—to prevent runway misidentification events.
