Microburst

The Microburst is one of the most dangerous weather hazards. It consists of air streams descending from the CB's clouds at a speeds that can reach 60Kt, spreading omni-directionally at the surface. They can last up to 5 minutes to dissipate. Generally they have a 4 Km diameter.

When an aircraft encounters a microburst, the IAS increases due to the increasing of the headwind (1), then experiences a downdraught (2) and finally a tailwind (3).

The microbursts can be described in two groups:

1. Wet microburst: A lot of precipitation associated. The magentas can be well depicted on the weather radar.
2. Dry microburst: It's more difficult to identify since the precipitation has evaporated before reaching the surface level.

Here is one animation of a microburst:

• Large aircraft coping with this phenomena

A sudden loss of speed associated with low altitude on the critical approach phase can be fatal for large jet aircraft in the case this microburst phenomena is not recognized and if all actions are not taken in due time by the crew. The time since the flight crew realizes this hazard with the additional one necessary to take the actions and speed up the aircraft may not be sufficient.

The most practical example of a microburst was the crash of the Tristar L1011 of the Delta Flight 191 at Dallas-Fort Worth International Airport on 2nd August 1985.On the following clip are the last two minutes of the flight.

Have anyone here ever experienced such similar event successfully ?


RWY 35-17