Vietnam has further tightened requirements on aircraft parked for extended periods, as numbers continue to increase amid the Covid-19 pandemic. The Civil Aviation Authority of Vietnam (CAAV) issued a directive on 21 June requiring aircraft operators to submit a detailed report of each aircraft’s maintenance activities while in storage, before it is returned to service. For aircraft returning after downtime of a month or less, operators must submit this information within 48h before it takes flight, and within 72h for aircraft grounded over a month. In January, CAAV issued directives requiring that airlines rotate between in-service and stored aircraft every month, to address safety risks associated with extended storage. Airlines are also not allowed to leave aircraft in storage for longer than one month. Operators would need to seek prior approval from CAAV to ground aircraft for repair and maintenance beyond a month.

The US Federal Aviation Administration will require additional inspections of the automated flight controls for certain Boeing 737 Max jets to tighten oversight of the aircraft features that contributed to two fatal crashes prior to their safety upgrades in November 2020. The FAA airworthiness directive scheduled for publication on 23 June will codify recommendations released in December by Boeing calling for checks of the flight controls, stabilizer trim and the primary and secondary aisle stand stabiliser on Max jets with more than 6,000 flight hours. The agency estimates that 72 Max jets registered in the USA and a total of 389 Max jets worldwide will be the first to require three repetitive inspections during existing maintenance schedules. If the additional inspections take 90 hours, then the FAA estimates that compliance with this order will be $7,650 per jet. The FAA in a separate notice highlights "the importance of these inspections" for government regulators and Max operators outside the USA. Failure of the flight controls or the stabiliser features on Max jets "combined with unusual flight maneuvers or with another flight control system failure, could result in reduced controllability of the airplane," the FAA states. Boeing states that it "fully supports the FAA mandate". The flight control software designed for Max aircraft called the Maneuvering Characteristics Augmentation System (MCAS) was intended to make the aircraft fly and respond similarly to earlier-generation 737NG aircraft. Investigations of two fatal crashes of Max jets during which 346 people died determined that a contributing factor was pilot response to MCAS software. The FAA in November allowed Max jets to return to service following safety upgrades made during the 20-month grounding. Boeing says 170 of 195 global aviation regulators have since reopened their airspace to Max jets. The US Department of Transportation's top inspector, however, began a new investigation in April to scrutinise how the FAA both grounded and recertificated Max jets.

Boeing’s 737 Max 10, the largest model in the 737 Max family, successfully completed its first flight on 18 June. The flight, from Renton Field in Renton, Washington to Boeing Field in Seattle, kicks off a comprehensive test programme for the variant, the Chicago-based airframer says in a same-day statement. It adds: “Boeing will work closely with regulators to certify the airplane prior to its scheduled entry into service in 2023.” 737 chief pilot Jennifer Henderson states: “The profile we flew allowed us to test the airplane's systems, flight controls and handling qualities, all of which checked out exactly as we expected." According to Boeing, the 737 Max 10 can carry up to 230 passengers and incorporates environmental improvements. Compared to 737NGs, carbon emissions are 14% lower and noise reduced by 50%. Stan Deal, president and chief executive of Boeing Commercial Airplanes states: “The [737 Max 10] is an important part of our customers' fleet plans, giving them more capacity, greater fuel efficiency and the best per-seat economics of any single-aisle airplane.”