Navis N4 Acheck: Container Gate-In Validation
Acheck is the Navis N4 validation that determines whether your container can gate into a Transnet Port Terminal. A failed acheck means a rejected truck, a wasted trip, and potential demurrage. Booking Buddy's built-in Validation Engine catches acheck failures before they happen.
Not affiliated with or endorsed by Kaleris or Transnet.
What Is Acheck in Navis N4?
Acheck (sometimes written as a-check, A-Check, or ACheck) is the automated validation process within Navis N4 that runs when a container arrives at a terminal gate. The acheck verifies that the container has a valid pre-advise record and that all mandatory fields are correct before allowing the container into the yard.
At every Transnet Port Terminal — including CTCT, DCT, CTMPT, Ngqura, and Port Elizabeth — the Navis N4 acheck is the final automated gatekeeper between a truck arriving at the gate and a container entering the terminal yard.
The acheck process validates multiple data points simultaneously:
- Pre-advise record exists and is active in Navis N4
- Container number format is valid (ISO 6346)
- Booking reference matches the terminal's records
- Carrier mode is correctly set (Truck for road transport)
- Vessel and voyage are valid and scheduled
- Gate-in date falls within the booking window
- No holds, flags, or restrictions on the container
What Happens When Acheck Fails
When a container fails the Navis N4 acheck at a Transnet terminal gate, the consequences are immediate and costly:
Truck Turned Away
The truck cannot enter the terminal. The driver, fuel, and time are wasted. The container must return to the depot.
Lost Booking Slot
The original booking slot is forfeited. Rebooking may only be available hours or days later, especially at high-demand terminals like DCT.
Demurrage Charges
While the container waits at the depot for a corrected pre-advise and new slot, demurrage charges accumulate.
Missed Vessel Cut-Off
If the delay pushes past the vessel's CY cut-off, the cargo rolls to the next sailing — often a week away.
Booking Buddy's Acheck-Compliant Validation
Booking Buddy includes a built-in Validation Engine that mirrors the Navis N4 acheck rules — checking every container beforeit's submitted to the terminal. This pre-submission validation catches the most common causes of acheck failure:
- Container number format — validated against ISO 6346 with check digit verification
- Carrier mode — always set to Truck automatically, eliminating the #1 cause of manual acheck failures
- Booking reference — matched from your import data with format validation
- Vessel and voyage — populated and validated from your booking sheet
- Gate-in date — verified to fall within the booking window
By catching these errors before they reach Navis N4, Booking Buddy prevents acheck failures at the gate — saving transporters the cost of wasted trips, lost slots, and demurrage charges at CTCT, DCT, CTMPT, and all Transnet Port Terminals.
Acheck Frequently Asked Questions
What is acheck in Navis N4?
Acheck (also written as a-check or A-Check) is the automated validation process in Navis N4 that verifies whether a container meets all the required conditions before it can gate into a Transnet Port Terminal. The acheck validates the pre-advise record, booking status, vessel/voyage assignment, carrier mode, and other mandatory fields. If any validation fails, the container is flagged and rejected at the gate.
Why does my container fail acheck?
Common reasons for acheck failure in Navis N4 include: incorrect or missing container number, wrong carrier mode (must be Truck), booking reference mismatch, vessel/voyage not found in the terminal's schedule, gate-in date outside the booking window, or a missing pre-advise record. Booking Buddy validates all these fields before submission, significantly reducing acheck failures.
How does Booking Buddy handle acheck validation?
Booking Buddy includes a built-in Validation Engine that checks every container against the same rules that Navis N4's acheck process uses — before submitting the pre-advise. This means container numbers are verified (ISO 6346 format), carrier mode is always set to Truck, booking references are matched, and vessel/voyage data is validated. By catching errors before they reach N4, Booking Buddy minimises acheck rejections.
Does acheck work the same at all Transnet terminals?
Yes. Acheck is a standard Navis N4 validation process that runs at all Transnet Port Terminals — CTCT (Cape Town Container Terminal), DCT (Durban Container Terminal), CTMPT (Cape Town Multi Purpose Terminal), Ngqura Container Terminal, and Port Elizabeth Container Terminal. The core validation rules are consistent across all TPT terminals, though specific operational requirements may vary.
What happens when acheck fails at the gate?
When a container fails acheck at the terminal gate, the truck is turned away and the container cannot enter the yard. This results in a wasted trip, additional fuel and driver costs, potential demurrage charges while the container waits at the depot, and the risk of missing the vessel cut-off. Fixing the pre-advise and rebooking a slot can take hours when done manually.
Stop failing acheck at the gate
Download Booking Buddy and pre-advise with built-in acheck validation — at every Transnet terminal.