Thrust reverser in the flair?

[2000flyer]

In the CE560's, especially the Ultras and Encores, I heard this was an issue due to nose gear collapses. Because of the design of the hydraulic system, the open-center type, theoretically, it's possible to have insufficient hydraulic pressure for that nose gear once TR's are deployed first prior. I'm not sure if it has been proven, but this is now SOP for the Citation 560s.

There is an SB out to correct this problem. The only one I heard of was a Bravo, however, NJA jumped on the band wagon and Cessna bought in and issed the SB.

 

[gear_guy]

Haven't met an aircraft yet that is uncontrollable with one reverser deployed.

Apparently you've never flown the aircraft I have. EVERY time only one bucket deployed on landing with nose up....I had to promptly change undies in FBO.

Try this in a lear or citation and you'll see what I mean.

 

[flx757]

I know we're talking Citations and not airliners, but at Alaska on the MD-80, it is prohibited to deploy the thrust reversers until the nose wheel is on the ground (to prevent dragging a bucket), and on the 717 the reversers are wired through ground shift, and WILL NOT deploy, whether you command them or not, until the nosewheel is on the ground.

At another operator where I flew MD-80s, the COM said that we may deploy the reversers when the mains are firmly on the gound, and you have "commenced nose lowering". However, like I mentioned, Alaska's prodedures prohibit deploying the reversers until the nosewheel is on the ground.

Bottom line. Comply with your aircraft's AFM, manufacturer's recommendations, or company policy. To do otherwise is asking for trouble. And usually, when you go looking for it, you will inevitably find it.

 

[Thedude]

Not to throw rocks here but something else I gotta know. How many of you jump the brakes rather than letting the rolling friction of the tires slow the a/c down. And I am talking about rather lengthy rwys here 8000'+.

 

[flx757]

I apply the brakes only after the aircraft has slowed significantly...say to about 80 kts. If it is a long runway, I use idle reverse to slow initially, then slowly come on the brakes. If the runway is shorter, then I will use a bit more reverse thrust, but still try to stay off the brakes until the aircraft has slowed.

 

[prpjt]

Wish I knew where it happened so I could look it up, but this story was told to me by a guy that was at recurrent. He was in the right seat of a Citation II. Short version:

Came in hot, flying pilot had a habit of throwing TR out with nose in air. As soon as the mains touched the FP deployed the buckets. He said the aircraft pitched to a deck angle of, his words" straight fukking up". It came down tail first and then the nose hammered the runway.

The breakdown was in the fact that this Capt. did this all the time and it was a habit. Though he knew he was fast, it was an involentary response to the mains touching. Half a million in damage and a record of an accident for each crew member. I understand that they must have been smokin' on final, but why get in the habit of doing something that has so little benefit, and a potentially disasterous downside.

 

[OtterFO]

My current job operates a Lear 31a on gravel strips between 3500' and 4800' long. We require the use of thrust reversers with the nose still in the air. There are two primary reasons for this. The Gravel Gaurd on the nose wheel is not adaquite to minimize the FOD damage to the leading edge of the wing and the engines we need to be going as slowly as possible for the nosewheel touch down, The biggest sin is to skip the nose wheel and get a double touchdown. The second reason, the 3500' strip aint much when you cross the fence at 117kts, in fact we couldn't do it under part 135 (we are public use). Our department went out and flight tested the aircraft and deployed only one TR, we found that the aircraft was controlable one bucket open and the engine spooled up with the nosewheel off the ground.

I realize this is a very specialized operation and not many people operate lears on gravel, but it is a procedure we train on and works for us in the lear 31a. There is some talk about replacing the 31a with a Citation Encore, the procedure may need to change then.

 

[Gulfstream 200]

On longer runways of course minimize the brakes, especially if brake temp is a consideration...(like MANY times).

I do however, apply brakes a tad bit just to be sure they are there....too many hours in old Learjets and Citations I guess.

and if someone is short final behind you...dont let that ciation roll down 8000' of runway please...

 

[TIS]

I just gotta say something here

Everyone who says it depends what type of airplane you're talking about is right on the money. Anyone who has an iron-clad rule that they follow isn't going to get everything they can out of their aircraft precisely because of that rigidity.

Before I go one let me say that I've read the posts and I know we were originally talking about a Citation but my point about this issue being aircraft specific is illustrated by talking abotu aircraft OTHER than a Citation.

A G-III, for example, has EXTREMELY effective reverse. The lateral control effects that result from only one reverser deploying are not insignificant but are also not uncontrollable. If it's me, I want the reversers out as soon as the mains are down - in a G-III. This is even more true in a G-IV because the deploy cycle takes longer and spoolup is considerably slower on the Tay than it is on the Spey.

Finally, I have to respond to something said further up the ladder here by G200 -

"..concentrate on preserving YOUR certificates, not HIS brakes."

The trouble with this attitude is that you should ALWAYS] be concentrating on preserving your brakes. They're not "his" brakes, they're YOURS! Stay off 'em when you can, let 'em cool when they need it, and ALWAYS be thinking about what happens if one or both stop working. I've had five brake failures in my career and trust me, you don't know how good you've got it when you have brakes until you don't have them anymore.

There is an old addage about driving that's appropriate here. The three most important things you must be able to make a car do are the following (in priority order, of course):

1. You must be able to AIM it.
2. You Must be able to STOP it.
3. You must be able to make it move under its own power.

Apply that to an airplane and an interesting thing happens because that stopping thing in #2 factors into that directional control thing in #1. A brake failure is VERY serious and far too few people understand this. It gets paid a lot of lip service but until you've had it go bad on you, braking ability is taken far too much for granted.

Off of soapbox now.

TIS

 

[Jeff Helgeson]

Lighten up, Francise!!!

yes folks, again, we are talking about a CITATION. Not a 727 or a GIV.

Many aircraft require flying the nose down, and unlocking the TRs cant do much harm I suppose..but on a Cessna or a Lear this if a bad habit that serves no purpose but to save your scumbag slave driver boss a few bucks on his brake life..

..concentrate on preserving YOUR certificates, not HIS brakes.

eh, heck maybe I will just stick to the DA50 types and forget about the TR issue all together.....

The original post was NOT A/C specific, even if the poster would appear to be corporate. This is a general discussion about TR technique and company policies.

However, I won't explain the differences between the DC9 and the MD80 or the various techniques and policies from company to company. Count to ten and think of your happy place!

To the original poster: consider yourself a "hired-gun", you should shoot when and how your employer tells you. If you follow that basic rule, it will usually keep you out of trouble with the company and your CP.

Jeff

PS: Hey Francise, what are your thoughts on liftdump vs. nose wheel touch down?......"I'm in my happy place, I'm in my happy place."

 

[Diesel]

at nja (yeah i know it's a frac not a corporate) but we beat the hell out of the Ultra's more than anyone could ever think of doing.

We had a bunch of ultra's with nose gear colapses. This was when we would deploy the tr's on main gear touch down.

Well we had a bunch of colapses after a while. Turns out cessna comes out with a bulletin saying that when the tr's come out there is a spike in the hydrolic system that can actually unlock the nose gear. So when the nose gear comes down it colapses.

So now we don't deploy until the gear is down. Guess what no more nose gear colapses.

Hope this helps.

 

[Stearmandriver]

Everyone who says it depends what type of airplane you're talking about is right on the money. Anyone who has an iron-clad rule that they follow isn't going to get everything they can out of their aircraft precisely because of that rigidity.
TIS

Right on, man. Well said. I guess the original post was about a citation, and I don't know a darn thing about citations, but enough people have said it's a bad idea to deploy the TR's in them with the nose still in the air that I'm sure it is. And, like others have said, the best course of action is to always follow manufacturer lims/recs and company SOP. However, since we're sharin' examples of different airplanes, I'll throw in this:

On the ERJ we always pop the buckets on main wheel touchdown. We're talking idle deploy, not spooled up. There's an A/G sensor on the nosewheel that won't allow the engines out of idle with the buckets deployed until the nose hits the ground anyway, so no worry there, but the point is: even with one reverser pinned, we still deploy the good one on MW touchdown with the nose in the air. It causes no directional control problems at all... not even a noticeable yaw. It does, however, provide some pretty effective aerodynamic braking. So, with some clear benefits and no risks in this case, it obviously isn't fair to say that you should NEVER deploy the TR's till the nose is on the ground.

Joe

 

[Rez O. Lewshun]

That is right, why not get the darn things deployed while the nose is coming down then transition with up to full reverse. This is especially important on short runways, when you (always ) carry too much thrust and float past the touchdown zone searching for that coveted "greaser"

Instead, get rid of the trust over the fence and use pitch to manage your speed to Vref minus 5 or 10 instead of touching down at Vref plus 5 or 10.
Now with the nose up, cause your bleeding off energy, don't just sit there in the seat, deploy TR at idle until you get the NW down, then increase thrust to slow down.

This applies to us stretch challenger guys at CMR/ASA/IndyAir/AWAC etc.. who have to fly pitch down on approach cause we don't have leading edge devices like a real jet. (sorry FK guys)

Brakes are for pilots who don't plan ahead or for ATC who says "can you make the next high speed?"

 

[TIS]

Hey, hey, hey

Only real jets have leading edge devices???

"This applies to us stretch challenger guys at CMR/ASA/IndyAir/AWAC etc.. who have to fly pitch down on approach cause we don't have leading edge devices like a real jet. (sorry FK guys)"

Let's take a look at a couple of planes here - the G-V and the Global Express are competing aircraft that claim to fulfill the same mission (but that's another dicsussion). One has LEDs and the other doesn't. One makes all its numbers the other doesn't.

One, just to get close to the numbers, had to be designed with a high aspect ratio wing. The high aspect ratio meant that the wing had to be fat to achieve the required lift characteristics. The fat wing meant that it had to have a very high degree of sweep in order to go fast enough. The high sweep meant that LEDs had to be added to get speeds down for takeoff and landing. The LEDs meant that something like five or six (I don't have my reference here with me) actuators had to be added to each wing to get 'em out when necessary.

In this one instance I don't see active leading edges as a plus. I see them as a repair for engineering that NEVER needed to happen if the engineering had been done right in the first place.

And just so you know the G-V achieves ref speeds under 110 knots at typical landing weights - WITHOUT LEDs! I'll take those numbers even if I have to fly nose low to do it any day!

Now, for all you Global guys, this isn't about bashing the Global. This is just about LEDs defining when you've made it to a real airplane and I don't think they do. That's all

TIS

 

[Gulfstream 200]

what does the GLEX not do that it says it does?