146 landing on all 3?

cheers here too!!

Thanx for that great explanation Wys….very interesting!:)

Ah now that’s a different question and can vary according to different things. There are 2 main factors affecting this plus an interesting fact about the TriStar that I’ll mention later.

Firstly – jet engines take a long time to go from idle to full power (e.g. in case of a go around) and the time difference between 2 identical engines accelerating can result in a period where one is at high power while the other is still at low power which will cause controllability problems at low speeds on approach. Therefore an approach must be flown with enough residual thrust set that if the thrust levers are advanced for a go around they will spool up evenly. Now when an aircraft is in the latter stages of an approach it will be configured with gear and flaps fully down creating a large amount of drag. On some aircraft the balance of thrust and drag results in an attitude (relationship between body angle and the horizontal) that is very nose low. On the 146 they open the rear mounted clam shell style brake which allows them to spool up more or increase the descent angle.

Secondly – The angle between the chord line of the wing and the oncoming airflow is called the angle of attack. I’m horrendously oversymplifying here but, think of the chord line of the wing being a straight line from the leading edge (front) of the wing to the trailing edge (back). In normal flight the flaps are up and the elevator is used to pitch the aircraft which rotates the chord line of the wing relative to the oncoming airflow. For slow speed flight we need a bigger curvature on the top surface of the wing so we put the flaps down. This increases the angle of attack which can be restored by lowering the nose which as a by-product enhances the cockpit view on landing. This is where the nose down approach angle comes from that this thread is all about. It will however require a very defined rotation in the flare to make the body angle correct for main gear touchdown.

Finally – thr TriStar used a totally different technique for landing using DLC (direct lift control). When the TriStar was on approach the automatics took control of the elevator to maintain a constant body angle relative to the horizontal while the pilots inputs fore and aft on the control column fed directly to the wing spoilers rather than the elevator. The thrust levers controlled speed. This guaranteed protection against a tail strike on landing. The system was actually designed by Lockheed for the StarFighter so that in a dog fight it could manoeuvre while always keeping its guns pointing at the target!

regards
wys

Yes..i meant the angle of approach of the CRJ.

Galdri – i think Kab means why does it Approach in such a steep nose down attitude,

Wys – Soz but been an anorak i’ve to point out the a British European 146, flying on behalf of AF 😉

This is getting a little bit prolonged…… No matter what anybody says, it is not correct for ANY aircraft to land on the nosewheel first, short field or otherwise. It is the sign of poor professionalism or poor aircraft handling skill (or both) to land on the nosegear first. Period.

Now KabirT,
The picture of CRJ you attached is of an aircraft above the flare hight. It has not started it´s flare, and the nose down attitude is perfectly normal during final appraoch with full flaps. If how ever the pilot did NOT flare, the next picture in the series would be of a CRJ with a broken nosegear skidding on its nose down the runway.

But none of the pictures that are being shown are at touchdown. All these aircraft are pre-flare.
Nobody has actually posted any pictures of the nosewheel on the ground with the main gear airborne!

Slightly aside from the topic but I thought I’d mention that the original picture on this thread is an Air France jet. Tomorrow morning I am flying for Air France from Orly to Marseille and back!

Wys what about the CRJ….its angle of landing in most pics has been shown gear first?

Sorry Coanda but 2 of the first 3 posts refer to landing nosewheel first so that is where the ‘suggestion’ is coming from.

Body angle is not a factor when referring to pure angle of attack. However during the landing flare the aircraft must transition form the attitude required for the desired descent rate for ground contact to the correct attitude for the airframe to arrive in. If the aircraft wing is correctly set up on the aircraft axis (for a landing configuration) these two angles will be the same. Any aircraft where they are not the same will be a pig to land. If as is claimed this aircraft is designed to land on unprepared strips the intent will be to touch down on the 2 sets of mainwheels first, apply maximum possible braking while keeping as much load as possible off the nosewheels.

regards
wys

its not suggesting that the aircraft is landing nosewheel first, its suggesting that the touchdown angle is such that all three wheels will touch the ground more or less at once, this is because of the low angle of attack. This is probably because the aircraft doesnt actually need to be at a high angle of attack to generate the lift require to support it. it could also be because the flap pitching moments force that angle of attack.

coanda

Rough field take off/landing technique involves protecting the nosewheels as much as possible rather than trying to put as much energy as possible through them!

regards
wys

Wasnt their some near misses at Canberra when stray trucks ended up on the active runway?

146 taking off

Lesson 1: How to make the passengers nervous!

Qantas 146 taking off at Canberra.

He made a pretty good landing…this is being demonstrated for the aircrafts great abilities to land on gravel and un-surfaced runways…it has the most powerful set of shock-absorbers and gears in civil aviation.

If he doesn’t flare I’d like to see the picture about 5 seconds later!

….

…….

They aren’t built specifically to take it they just happen to be able to cope with a very small amount of it at very, very small angles. Do it deliberately in a light aircraft or an airliner and you will very soon be the first one on the scene of an accident.
Someone her must have a picture of an old Stratocruiser about to touch down nosewheel first. Anyone? A330C?

regards
wys

Although its a bad habit very true….but some airlines are built to take it…BAe 146 CRJ series and specialy the AN 72.

Wheelbarrowing is a surefire way of busting the nosegear and isn’t a recommended technique in any aircraft ops manual. The geometry of some aircraft (coupled with bad piloting) make it more prone to this than others. A classic case of this was the Stratocruiser which could regularly be seen wheelbarrowing into Heathrow!