How do commercial jets slow down when Landing?

[jwilliams3]

Other than brakes on the landing gear, what is the sound from the engines when landing and making the big slow down?

 

[steveinaz]

Thrust reverser. Inflight its part of the engine cowl.

 

[Todd G]

Thrust-Reversers. Big do-hickies that point the exhaust forward, then rev 'em up.

 

[scotmartin]

Check out this link:



http://sitemaker.umich.edu/thrust.reverser/see_thrust_reverser_deployed



Scot

 

[RT66DOC]

Ahh... One of My Favorite Topics

Reversers - aka clamshells, buckets, etc.



Reversers are deployed after touchdown and operated only within a specific speed range, e. g. , 100-60 kts (or whatever, I just made that up to illustrate the point. ). They slow the aircraft to a speed where the wheel brakes can be used without burning them out, blowing tires, etc. Most heavy jets have auto-brake and anti-skid. I think I recall reading about another feature that starts the wheels spinning before they touch down. I've always enjoyed watching the blue smoke puffs when the rubber meets the road, so to speak.



BTW, FAA doesn't exactly condone deploying reversers prior to touchdown in an ill-advised attempt to increase rate of descent or landing rollout. Some pilots actually used to do that years ago - only problem is if you don't get it just right... splat.



Here's a pic of a 747 throttle quadrant which shows throttle and reverser levers - all four each of 'em. I believe the reversers are the top set with numbers on them. To deploy them the pilot pulls them up with fingers in claw position while palms of hand are on the larger throttle levers. Once the reverse levers are pulled up and back they're held in the position while the throttles are advanced - then the procedure is reversed to shut down the reverse.



Maybe there are some TDR guys here who are alot more familiar with the flight deck of a 747 than I am who can correct/clarify any errors in this.



Truth is I've never actually flown a 747 but I did sleep at a Holiday Inn last night.

 

[RT66DOC]

Gee, Aren't You Glad You Asked?

I almost forgot.



Some prop planes, i. e. , turboprops reduce speed after landing by reversing props. They have variable pitch props which can be set to reverse thrust - aka "Beta Range. " This feature also allows them to back up without launch shudder. I just happen to have ( )a pic of one of these A/C, the venerable PT-6A mounted on a King Air - see below.



Back to thrust reversers on jets for a sec. On one flight where I was serving as SLF (self loading freight) the captain apparently grew weary of waiting for a push-back from the gate so he backed out using the thrust reversers. This maneuver caught the attention of all other SLFs on the flight but was way cool IMHO.

 

[AfterBurner]

How about slats.

I rode on one of those jets that reversed before hitting the runway. very exciting, i'm certain we took some leaves off the palm trees!

 

[AfterBurner]

RT66DOC,

That looks like you pulled that cockpit off of MS Flight Sim or something! good graphics though, had me fooled the first time!

 

[klenger]

Thrust reversers, slats, flaps, spoilers, brakes, and for some airplanes (if all else fails) a drag chute.

 

[NPloysa]

There has been a few in-flight disasters due to accidental thrust reverser deployment. Now some aircraft have safety systems to prevent that like landing gear squat switches, that only activate when there is weight on the nose gear and the power lever has been to flight idle.



Smaller craft, business jets, commuters, etc, have clamshells.



Mid-size have cascade-type.



Larger high-bypass engines use petal door reversers.



Also, the DC-8 was able to use thrust reversers in flight to slow, due it's very clean aerodynamics.



Nick

 

[WDaniels]

Not all jets have a thrust reversing system. The Air Force listened to some general one time when he said that we didn't need thrust reversers on the KC-135R and they paid to have them taken off. (Oooooo, that was a smart move. NOT!) So now all we have are the brakes on the trucks. (trucks are a part of the landing gear for those of you who didn't know)

WD

 

[RT66DOC]

RT66DOC,

That looks like you pulled that cockpit off of MS Flight Sim or something! good graphics though, had me fooled the first time!

Right you are AfterBurner. It's not MSFS but it's a 747 panel from an add-on flightsim. I used that to illustrate the concept as it was sooo easy to lift the graphic and post it here and, unfortunately, I don't have a real one in my hangar.



BTW, has anybody seen the speed brakes on a Mooney? Bravo or Ovation. Very slick and very functional. Used to slow the A/C in flight for descent and/or while setting up an approach.



We also ought at least to give honorable mention to the Navy method of stopping an aircraft on a flight deck.

 

[Jim Fulmer]

Other than brakes on the landing gear, what is the sound from the engines when landing and making the big slow down?

Finally something in my world... ... ask away Justin.



T/R's... Thrust Reversers just deflect air coming from the engine's core in some and fan (by-pass air) in others, on engines like on our plane it deflects forward and up in a 30 degree angle so not to stir trash (FOD) up from the runway and ingest it and the thrust is limited to 87% because after that it doesn't do much more.



Jim

 

[klenger]

We also ought at least to give honorable mention to the Navy method of stopping an aircraft on a flight deck.

Another honorable mention is, if all else fails, the ditch or river at the end of the runway.

 

[RT66DOC]

Finally something in my world... ... ask away Justin.

Hi Jim



So... is E-6 your A/C or your paygrade?



Sorry, I couldn't resist.



Thank you for your service.

 

[RT66DOC]

Another honorable mention is, if all else fails, the ditch or river at the end of the runway.

"Any idiot can land on 10,000 feet of concrete. "

---anonymous Navy Carrier Pilot

 

[4xquadrod]

I would say they power down, nose it up, drop some flaps, to give it more drag and control the fall they created.

 

[RT66DOC]

I would say they power down, nose it up, drop some flaps, to give it more drag and control the fall they created.

In that order? What are we talkin about here - flying or drinking? :-laf

 

[4xquadrod]

Yup, that about sums it up Mr. RT66DOC!

 

[RT66DOC]

Ah yes, the common bond. Hard to beat the TDR mentality, eh?