OVERWEIGHT LANDING

Definition
All aircraft are certified to land at a particular maximum landing weight. Any landing carried out in excess of that weight is termed as an overweight landing.


Design
Landing at or below overweight landing ensures that normal performance margins as per certification are ensured.
Regulatory certification criteria require that landing gear design be based on 

• A sink rate of 10ft/sec at the maximum landing weight, and 
• A sink rate of 6ft/sec   at the maximum takeoff weight.

Commercial airliners normally make a sink rate of 2-3 ft/sec. A so called hard landing barely exceeds 6ft/sec.

When would it be required to carry out overweight landing?

• In case of any uncontrollable fire, damage, malfunction, etc
• In case of crew incapacitation, medical cases on board requiring immediate attention, etc.
• Any other situation where crew perceive an immediate landing is required.

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Is it safe to carry out overweight landing?

Enough debates have been done on this subject. Airline crew are trained to handle overweight landing and the performance criteria and design aspects have been catered to allow for such an event should an emergency arise. Overweight landing provision is limited only to non-normal operation and crew shall not land overweight  on a normal flight  due to direct routings and strong tailwinds.

Aircraft are designed with adequate strength margins for overweight landings.Performance margins are generally well above maximum landing weight. Brakes are designed to withstand reject takeoff at the maximum takeoff weight. So oversight landing should not be a problem.

Is there a special procedure for maintenance after landing overweight?

An overweight landing entails a maintenance procedure even if the landing was smooth!!!!!

Inspections aim at checking for structural distress.

Is there a procedure for crew to follow?

Crew have a procedure to follow which aims at sensitizing crew on the sink rate for touchdown and the technique thereof.

Summary

Overweight landing provision is allowed for by the manufacturer in case of exigencies and the procedure is outlined.Design and performance margins allow for overweight landing.Overweight landing is prohibited in a normal operation. Procedures are outlined for the crew and the maintenance teams  to follow in the event of an overweight landing.