The maximum landing weight (MLW) is the maximum
aircraft gross weight due to design or operational limitations at which an
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
is permitted to land. The MLW is set in order to ensure safe landings; if an aircraft weighs too heavy during touchdown, it may suffer structural damage or even break apart upon landing. Aircraft also have a
maximum take-off weight
The maximum takeoff weight (MTOW) or maximum gross takeoff weight (MGTOW) or maximum takeoff mass (MTOM) of an aircraft is the maximum weight at which the pilot is allowed to attempt to takeoff, take off, due to structural or other limits. The a ...
, which is almost always higher than the maximum landing weight, so that an aircraft can weigh less upon landing due to burning fuel during the flight.
The operation landing weight may be limited to a weight lower than the maximum landing weight by the most restrictive of the following requirements:
* Aircraft performance requirements for a given altitude and temperature:
:*landing field length requirements,
:*approach and landing climb requirements.
* Noise requirements
If the flight has been of unusually short duration, such as due to an emergency just after takeoff requiring a return to the airport, it may be necessary to
dump fuel to reduce the landing weight.
Some aircraft are unable to dump fuel, however. For example, on 3 February 2020,
Air Canada
Air Canada is the flag carrier and the largest airline of Canada by the size and passengers carried. Air Canada maintains its headquarters in the borough of Saint-Laurent, Montreal, Quebec. The airline, founded in 1937, provides scheduled and ...
Flight 837, a
Boeing 767-300
The Boeing 767 is an American wide-body aircraft developed and manufactured by Boeing Commercial Airplanes.
The aircraft was launched as the 7X7 program on July 14, 1978, the prototype first flew on September 26, 1981, and it was certified on ...
, suffered a rear tyre failure during take-off at
Madrid–Barajas Airport on its way to Toronto, causing its left engine to catch fire. The pilots managed to extinguish it by shutting the engine down, but as 767-300s are not designed for fuel dumping, it had to stay in a single-engine
holding pattern
In aviation, holding (or flying a hold) is a maneuver designed to delay an aircraft already in flight while keeping it within a specified airspace.
Implementation
A holding pattern for instrument flight rules (IFR) aircraft is usually a racet ...
for over 4 hours to burn fuel and achieve its maximum landing weight, while an
SAF fighter reported minimal damage to the landing gear. The plane landed safely and nobody was injured.
Sometimes the emergency may be so pressing that the aircraft has no time to dump or burn fuel in order to achieve its maximum landing weight before touchdown; in that case, a risky overweight landing may be permitted.
In other cases, the flight crew may fail to dump fuel when it still had the time to do so before landing, leading to fatal accidents such as
Aeroflot Flight 1492
Aeroflot Flight 1492 was a scheduled domestic passenger flight operated by Aeroflot from Moscow–Sheremetyevo to Murmansk, Russia. On 5 May 2019, the Sukhoi Superjet 100 aircraft operating the flight was climbing out when it was struck by lig ...
on 5 May 2019, where an apparently needlessly overweight landing turned into a crash that killed 41 of the 78 people on board.
Where aircraft overweight landing is permitted, a structural inspection or evaluation of the touch-down loads before the next aircraft operation will be required in case damage has occurred.
References
Aircraft operations
Aircraft weight measurements
Aviation safety
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