HASELL

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In aviation, in Australia, the UK, New Zealand and elsewhere, HASELL (sometimes spelled HASEL) is a standard mnemonic to prompt a series of checks prior to carrying out many types of manoeuvres, such as stalls, spins, spiral dives or aerobatics.

A HASELL check is carried out in an aircraft whenever carrying out a maneuver that could result in the loss of control of the aircraft or when a dangerous maneuver that could affect other aircraft in the vicinity is about to be undergone. These could include stalls, spins, slow flight, spiral dives and any other air exercise that could endanger the life of others or your own.

The HASELL acronym stands for:

Height - sufficient to recover
Airframe - rated for the manoeuvre, flaps and landing gear as required, trimmed.
Security - hatches and harnesses secure, no loose items in cockpit, gyros caged.
Engine - running normally, fuel sufficient for manoeuvre, no carb icing.
Location - Airfields, airspace, built up areas, Clouds
Lookout - inspection turn to make sure area is clear around and below

When several manoeuvres are to be flown, after the initial HASELL check, the shorter mnemonic HELL can be used for subsequent manoeuvres.

[edit] Expanded definitions for each letter

H: 'Height - The pilot should first check his altitude to determine whether the aircraft is an altitude which will provide sufficient ground clearance to regain control after a spin. This altitude varies depending on the aircraft and the exercise you will be doing. For example, a spin requires more height than slow flight or stall, since an airplane can lose 1,000 feet in a short time in a spin.

A: Airframe - The pilot determines the configuration of aircraft for the exercise: the position of wing flaps, cowl flaps, landing gear, etc.

S: Security - The pilot checks to see if there are any unsecured items in the aircraft which could cause injury or damage if something went wrong. This can include removing sharp objects from pockets, storing books in a secured bag, making sure the seat belts of unoccupied seats are done up, making sure that passengers are all wearing seat belts, and securing cargo by use of baggage nets or tiedown straps.

E: Engine The pilot determines what setting the engine will be in, will the alternate air supply or carburetor heat be on during the exercise. A decision is made on whether the electric (supplemental) fuel pump also be on (a common precaution in case the mechanical fuel pump were to fail).

L: Location - The pilot selects a location away from controlled airspace, towns, aerodromes, and other aircraft. Maneuvers are typically done within range of a suitable forced landing field, and not over open water or high ground.

L: Lookout - The pilot inspects the area, turns 90, 180, or 360 degrees to look for aircraft. In a high wing aircraft, this is generally conducted to the left as to allow the pilot to see any aircraft below them.