Each of these is a refusal this regime lets a counterparty attempt, paired with the answer to it. Reading them before you write is worth more than any amount of polish on the letter itself.
"The Standards are not law"
high likelihoodThe carrier points out that the Consumer Dispute Resolution Standards are a notification rather than a statute and says it is not bound to pay.
What answers it
Strictly true and practically weak. The Standards are the criteria the Korea Consumer Agency and the Consumer Dispute Settlement Commission apply, and under the Framework Act they are the default where the parties have not agreed something else. Ask the carrier what standard it says applies instead and why it is more appropriate than the one the Fair Trade Commission published. Then file with the Korea Consumer Agency, where the published standard is the starting point.
소비자기본법 제16조제2항 (Framework Act on Consumers, Art. 16(2)) — 제16조제2항
"It was an unforeseen maintenance issue affecting safety"
high likelihoodThe carrier invokes the safety-maintenance carve-out, which is the most-used exemption in Korean practice.
What answers it
The carve-out is for an unforeseen requirement affecting safety, not for maintenance generally. Ask what the defect was, when it was discovered, and why it was not found at the previous scheduled check. A part that was known to be near end of life, or a deferral that ran out, is not unforeseen. The carrier has to establish this, not assert it.
소비자분쟁해결기준 (공정거래위원회 고시), 별표 II — 항공업 — 별표 II, 항공업 (domestic and international passenger carriage)
Miles or a voucher instead of the figure
high likelihoodThe carrier offers mileage or a travel voucher, often nominally worth more than the standard figure.
What answers it
The Standards state percentages of the fare and dollar amounts, not mileage. You may accept miles if you want them, and you are not obliged to. Say so plainly and ask for the cash figure under 소비자분쟁해결기준. Carriers reserve mileage offers for passengers who do not know the standard exists.
소비자분쟁해결기준 (공정거래위원회 고시), 별표 II — 항공업 — 별표 II, 항공업 (domestic and international passenger carriage)