Aviation Safety

Acknowledgement of sources: Aviation Safety January 2004 The Internet

Aviation Safety can be looked at from two points of view: can be looked at from two points of view: 1 accident and incident statistics2 flying techniques that reduce their causes

Re 2 flying techniques that reduce their causes For this presentation we’ll concentrate on damage to the nose gear due to improper landing technique and maintenance

We may see this on the ramp

The aftermath of abuse: A flat nose strut and a puddle of hydraulic fluid

Or this

After landing the trim tab is still set for cruise

Here is something that could fool any pilot

In flight the nose strut is fully extended, thus upon landing the nose wheel is much closer to the runway than the pilot may think

Not quite our airplane type, but you get point the point

This also means that a low strut should not be casually given a shot of high-pressure N 2 Instead, it should be adjusted to the manufacturer’s specification

Let’s take a look at the construction of the nose gear

What can cause damage is that due to a hard touchdown or fast derotation, the ‘O’ ring, that seals the strut, rolls up and becomes twisted; and a leak results A dirty or corroded strut will aggravate that

Fast derotation may also be caused by aggressive braking Therefore when simulating a short-field landing also simulate the hard braking

A non-steerable, free-castering nose gear is especially vulnerable to not holding the nose off upon landing

Pretty flimsy

By comparison the nose gear on an airliner may look indestructible

But keep in mind the weight difference

Perhaps it would be a good idea to just beef up the nose gear a little on our type of airplanes

That would make for easy towing too

A quick look at Shimmy Here it is shown looking down on the nose wheel

This phenomenon is more violent if there is more rotational energy, which equals: Note that it is proportional to the square of the touchdown speed

What else should we be paying attention to ?

The effect of touchdown speed on the angle of attack

The “big” boys aren’t immume to this either, as is shown in the next few slides

That is not just a little paint blister

Not quite as bad as the next one though

Or the next one

However, here the cause is not landing too flat, but excessive derotation after the mains have touched down The problem was serious enough that Boeing produced a crew training video

The lesson for us is that we should relax the backpressure on the yoke gently

One more Slide (that has nothing to do with this topic)

That’s all folks !