PPRuNe Forums - View Single Post - Speed reduction from Vref+20 to Vref+15 in Boeing
Old 16th Sep 2018, 09:49
  #14 (permalink)  
Goldenrivett
 
Join Date: Jan 2014
Location: N5109.2W10.5
Posts: 720
Likes: 0
Received 0 Likes on 0 Posts
Hi LeadSled,
I agree with your conclusion.

This Boeing patent https://patents.google.com/patent/US5823479A/en says
"In addition to a maximum value, during landing, it is also desirable that the pitch attitude not exceed a minimum value. During approach, the main landing gear and nose gear of an airplane are lowered. Because the nose gear is not designed to withstand the impact of airplane touchdown, it is crucial to land the airplane so that the main landing gear makes contact with the ground first. The separation between the nose gear and the ground when the main landing gear contacts the ground is known as the nose gear contact margin. In order to avoid nose gear first landings, a minimum pitch attitude, commonly referred to as a most nose gear critical flight condition, is defined. Landing at pitch attitudes equal to or greater than the minimum value for the most nose gear critical flight condition ensures that the main landing gear touchdown precedes the nose gear touchdown by a predetermined value. The predetermined value is known as the nose gear contact margin requirement. This requirement is also in degrees and is defined by the angle between the runway and a line extending between the main landing gear and the nose gear on the airplane."
Goldenrivett is offline