The sudden closure of airspace over Afghanistan on August 16, 2021, compelled two Air India flights to divert and make unforeseen fuel halts, pushing the crew over duty hours.

The Afghanistan Civil Aviation Authority issued a Notice to Airmen (NOTAM) on August 16, 2021, advising transiting flights to reroute due to the airspace being changed to uncontrolled.

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The NOTAM affected Air India flights AI126 from Chicago to New Delhi and AI174 from San Francisco to New Delhi, in the air when the warning was issued. Due to the additional routing required, both planes had to make unexpected stops for fuel in the United Arab Emirates. 

As per Flightradar24, AI126 had departed from O'Hare International Airport (ORD) at 12:44 PM local time. The Boeing 777 was proceeding to enter the Afghanistan region at 10:00 AM local time, when it seemed like the crew acknowledged the NOTAM, forcing them to make an apparent sharp turn to the Turkmenistan region. This eventually caused the flight to be diverted to Sharjah International Airport (SHJ) in the United Arab Emirates, landing at 12:07 PM local time.

AI174 departed San Francisco International Airport (SFO) at 11:15 AM local time. According to the Hindustan Times, the flight crew was informed of the NOTAM in time to avoid the Afghanistan airspace altogether and instead proceed to SHJ, landing at 13:35 local time.

Due to the additional fuel stops in the UAE, the Air India crew exceeded their flight time duty limit as set by the Directorate General of Civil Aviation (DGCA), their union told the Hindustan Times.  Instead of waiting for a fresh crew to operate the flights from SHJ, the pilots of both the flights decided to fly their aircraft to the original destination, Indira Gandhi International Airport (DEL).

As per ICAO, the maximum flight duty limits for any operating aircrew in a period are limited to prevent the stress caused by the lack of sleep and provide the crew with maximum rest. However, crew can opt to exceed those limits within good reason, if they feel able to continue to fly.