At 19:49 07/12/2009, you wrote:
J'ai passé la semaine sur ces satanés fichiers et en heures de
recherches sur l'Internet, et je ne reviens vous taquiner qu'aujourd'hui.
Je crois que ces recherches ont été assez fructueuses mais je bute
sur le concept de 'pitch altitude' qui semble être un facteur très
important de la phase d'atterrissage.
Voir l'extrait ci-dessous (en bleu et en anglais)
Landings
In a typical approach, the pitch altitude is 3º-4º for the DC10. As
speed is decreased to threshold speed, the pitch altitude will
increase about 1º. Landing flare is normally initiated at
approximately 30-40ft above the runway surface.
With a typical low rate of descent at touchdown, the pitch altitude
will normally be 3º - 4º. Landing with a 50 flap setting decreases
the pitch altitude approximately 1º over that for 35 flap. There is
ample tail ground clearance for a normal 35 or 50-flap approach and
landing. Fuselage contact with the runway will not occur until
approximately 7º pitch altitude.
One of the most important factors leading to ground contact with the
tail is holding off in the flare, allowing the airplane to float
prior to touchdown. As airspeed decreases below the normal threshold
speed, pitch altitude will begin to increase significantly if a
level flight path is maintained. The result will be an excessively
high body angle at touchdown with significantly reduced tail
clearance or tail strike.There is no substitute for a well-executed
stabilised approach to properly position the airplane for a
consistent flare and touchdown. Other than a stabilized, on profile
approach creates an exposure to a number of unnecessary risks,
including tail strike. If touchdown occurs with a higher than normal
pitch altitude, the nose must be lowered promptly to prevent spoiler
deployment from further increasing the pitch altitude.
J'ai beau chercher, je ne trouve rien de satisfaisant et je ne pense
pas que 'altitude d'inclinaison' veuille dire grand-chose.
Auriez-vous plus d'informations ?
Merci d'avance.
Salut Bernard,
J'ai surtout l'impression qu'il s'agit de "pitch attitude", autrement
dit du cabré en approche, qu'on essaie de diminuer en aviation
commerciale pour réduire l'inconfort des passagers tout en conservant
une pente de descente suffisante..
Guy R.
