when vour vessel enter NOx ECA area which fuel u will use, suppose your NOx limit is higher in that ECA area, what will be your actions,

Answer

So, if the ship is entering an area that is both a SOx ECA and a NOx ECA, I would use ECA-compliant fuel, max 0.10% sulphur, unless an approved equivalent such as EGCS is used for SOx compliance. The fuel changeover must be completed before entry, with date, time, position and quantity recorded as required.

For NOx, I would ensure the engine is operating in its Tier III certified mode, for example by putting the approved system into service:

• SCR in operation, correct urea dosing, catalyst temperature and alarms checked.
• EGR in operation, with correct recirculation rate, scrubber/cooler, water treatment and alarms.
• Dual-fuel lean-burn gas mode, if that is the certified Tier III mode.
• Any other approved configuration exactly as stated in the EIAPP Certificate and NOx Technical File.

IMO requires in-service compliance to be demonstrated in accordance with the NOx Technical Code and the engine’s approved certification arrangement.

As Chief Engineer, I would treat that as a statutory non-compliance and act immediately.

First, I would verify that the reading is genuine: check engine load/rpm, NOx-monitor calibration if fitted, sensor condition, and whether the engine is actually in the correct Tier III mode.

Then I would check the NOx-control system depending on the installation. For SCR: urea level, dosing pump, injection nozzle, catalyst temperature, exhaust bypass, differential pressure and alarms. For EGR: EGR valve position, recirculation rate, blower, cooler, scrubber/water system and oxygen/scavenge parameters. For dual-fuel engines: verify correct gas mode, gas quality, pilot quantity and combustion settings.

If the engine cannot be brought back within the certified Tier III limit, So, as Chief Engineer, I would:

1. Inform Master and company/DPA immediately.
2. Record time, position, engine load, alarm/failure, Tier III status and corrective actions.
3. Minimize emissions where practicable—e.g. reduce engine load if this materially reduces NOx and remains navigationally safe.
4. Contact the flag Administration/RO and, as appropriate, the relevant coastal/port State for instructions if compliance cannot quickly be restored.
5. Arrange repair at the earliest practicable opportunity. Depending on instructions and circumstances, this could mean proceeding directly to a repair port or leaving the NOx ECA rather than continuing normal commercial operation indefinitely.