Your examiner asks: "What certificates evidence Annex VI compliance, and what does each cover?"

A. The International Air Pollution Prevention (IAPP) Certificate covers the ship overall (SOx/fuel sulphur content, NOx-related equipment where applicable, VOC management plan for relevant tankers, incinerator approval); the Engine International Air Pollution Prevention (EIAPP) Certificate is issued per qualifying diesel engine, confirming compliance with the applicable NOx Technical Code tier (I/II/III) and is supported by that engine's NOx Technical File; the International Energy Efficiency Certificate (IEEC) evidences the ship's EEDI (or EEXI for existing ships) compliance and that a SEEMP is on board.

B. A single IAPP Certificate covers engines, energy efficiency and ozone-depleting substances with no separate engine-specific or energy-efficiency certificate.

C. The EIAPP Certificate is issued to the ship as a whole, not per engine, and has no link to the NOx Technical Code.

D. The IEEC is only required for passenger ships; cargo ships have no energy-efficiency certification requirement under Annex VI.

A. An Emission Control Area (ECA) is a designated sea area (e.g. Baltic Sea, North Sea, North American coasts, Caribbean) with stricter SOx (and in some, NOx Tier III) limits than the global rule. The global sulphur cap is 0.50% m/m (since 1 January 2020, IMO 2020); inside a SOx ECA the limit is stricter, commonly cited at 0.10% m/m, requiring either low-sulphur fuel, approved equivalent means (e.g. an exhaust gas cleaning/scrubber system), or use of an alternative fuel meeting the limit.

B. ECAs apply only to NOx and have no relationship to fuel sulphur content at all.

C. The global sulphur cap and the ECA sulphur cap are numerically identical; ECAs only add extra reporting paperwork.

D. ECA status applies only to passenger vessels; cargo ships transiting the same waters are exempt from the ECA sulphur limit.

A. A documented changeover procedure must be followed before ECA entry, completed in good time so that all fuel oil systems are flushed of higher-sulphur fuel before entry; the date, time, position and fuel oil tank quantities at the time of changeover (both entry and exit) must be logged — this changeover log is a specific item PSC and class auditors check, and is also entered in/cross-referenced with the Oil Record Book.

B. Fuel changeover may be completed instantaneously at the ECA boundary with no advance flushing of fuel lines required.

C. Only the changeover into the ECA needs to be logged; the changeover back to higher-sulphur fuel on exit has no logging requirement.

D. Fuel changeover logging is a class society recommendation only, with no regulatory basis under Annex VI.