Pilots are not allowed to fly if they have alcohol in their system.

The Ministry of Transport has drafted regulations to test all pilots for alcohol and other stimulants before they undertake flight missions.

According to the draft amendments to several articles related to civil aviation safety by the Ministry of Transport, aircraft operators must ensure that all crew members have no alcohol in their blood or breath when performing flight missions over Vietnamese territory and report any violations to the Civil Aviation Authority of Vietnam within 24 hours of detecting any alcohol-related violations.

Flight crew members are not permitted to perform flight duties while under the influence of alcohol, whether in the blood or breath, or while under the influence of psychoactive substances that impair cognition and behavior, potentially reducing alertness, competence, and the ability to perform their duties safely.

Furthermore, flight crew members have the right to refuse to perform duties with individuals who violate these regulations and are responsible for reporting to the aircraft operator when they detect the use of alcohol or psychotropic substances that affect the cognitive and behavioral abilities of those performing duties on the flight.

Flight crew members are subject to psychotropic drug testing when requested by competent state authorities. Failure to comply with the testing regulations of competent state authorities will result in a ban from performing flight missions to and from Vietnam.

Furthermore, foreign aircraft operators operating flights in Vietnam under aircraft lease agreements with Vietnamese aircraft operators must comply with the above regulations. Failure to comply with these regulations will result in the foreign aircraft operator being barred from operating flights in Vietnam.

According to the circular, psychostimulants include: alcohol, opium, painkillers and sleeping pills, cocaine, hallucinogens, narcotics, and prohibited solvents, but do not include coffee and tobacco.

Source: https://vietnamnet.vn/phi-cong-khong-duoc-bay-neu-co-nong-do-con-2336998.html