Airprox Serious incident Boeing 777-F6N D-AALJ, Monday 5 May 2025

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Date:	Monday 5 May 2025
Time:	01:00 LT
Type:	Boeing 777-F6N
Owner/operator:	Aerologic
Registration:	D-AALJ
MSN:	37710/782
Year of manufacture:	2009
Engine model:	General Electric GE90
Fatalities:	Fatalities: 0 / Occupants: 2
Other fatalities:	0
Aircraft damage:	None
Category:	Serious incident
Location:	near Waypoint PARAR - Indian Ocean
Phase:	En route
Nature:	Cargo
Departure airport:	Frankfurt International Airport (FRA/EDDF)
Destination airport:	Mumbai-Chhatrapati Shivaji International Airport (BOM/VABB)
Investigating agency:	AAIB India
Confidence Rating:	Accident investigation report completed and information captured

Narrative:
Aerologic flight 3S622, a Boeing 777-F6N (D-AALJ), and Air Arabia flight G9405, an Airbus A320-214 (A6-AOS), were involved in a serious airprox incident near Waypoint PARAR in the Mumbai FIR.

Both aircraft were operating on converging tracks that merged at waypoint VAXIM and continued on the same route segment (P307–PARAR–N571–SUGID). Both were under the surveillance control of Muscat Sector ‘ALPHA control’ before being handed over to Mumbai Oceanic Control OCC (North).
During the period in question, the Karachi FIR was closed for Indian operated and Indian registered aircraft due to a NOTAM (A0220/25), leading to a significant increase in traffic density over the P307–PARAR–N571 route. This increased the workload for both Muscat and Mumbai controllers.
The minimum required longitudinal time separation at waypoint PARAR in Mumbai FIR for aircraft at the same flight level is 10 minutes. However, both aircraft passed PARAR eastbound at the same level, with a separation of only 3 minutes, and the slower aircraft was positioned ahead of the faster one.

Probable Causes:
a) Coordination failure: The transferring controller (Muscat control) missed climbing ABY405 to the coordinated level FL370 prior to transfer due to increased workload.
b) Delayed action: The accepting controller (Mumbai OCC) was engaged in handling estimate coordination over the hotline in the absence of a dedicated coordinator, which led to reduced monitoring of the Controller’s Work Position (CCWS) and hence a delayed response in resolving traffic.

Contributory factors:
a) Non-generation of conflict alert in both ATC units.

Accident investigation: