CRJ Takeoffs and Landings

[GCD]

OK, I don't profess to be the all-knowing expert, but I've had experience as a CRJ Captain/Sim instructor/ground & systems instructor for the U.S. launch customer. Since then, I went away to fly the big Boeing for a few years, but circumstances have landed me back into the CRJ. I love the CRJ, but I have noticed that some folks were either not trained well, or have ignored their training. In light of that I will stick my neck out for ridicule and give my two cents worth, hoping that I can make a positive impact on our profession.

Takeoff thrust setting - There are some very good reasons why your FSM or FCOM says to advance the thrust to 70% N1, stabilize, then set takeoff thrust. The stabilization at 70% N1 is to allow for symmetric spool up. Both engines may spool up to 70% N1 at a different rate, but once stabilized at 70%, it is more likely they will spool to takeoff thrust more evenly. Also, by allowing the engines to stabilize at 70% N1, you are checking two other things, proper airflow through the compressor and that N1 is speed controlled to avoid an overspeed when setting takeoff thrust. Setting takeoff thrust from idle is really poor technique and even causes impulse stress to the turbine blades, causing a creep in the blades and eventually failure of the turbine blades, if done very many times.

Landing and rollout - Folks, despite what the urban legend is, the reverse thrust from the CF34 is VERY effective. It takes proper training and practice to properly deploy the thrust reverse in the CRJ. I have seen too many CRJ folks slam on the brakes at touchdown and not even crack the reversers. Very poor technique. The brakes are only 20% effective above 80 knots, and don't reach 80 - 85% effectiveness until 80 knots and below.

Reverse thrust, on the other hand, is 80 - 85% effective above 80 knots and loses effectivenes below 70 knots, where the brakes are more effective. All you are doing by applying brakes above 80 knots is creating unwanted heat.

My recommendation, and this is how we taught it in the past days, is mains down, nose down, reverse, then brakes. As soon as the mains touch, squeze the reverse triggers, lower the nose, and by the time the nose is on the ground you will have heard the "click, click" and reverse is available. Then pull straight to the stops, without hesitation. By the time full reverse is spooled up, you will be at around 100 knots (+ or -). It is unlikely you will reach the reverse N1 limitation, but it is smart to crosscheck. Around 90 knots, start thinking brakes. At 80 knots, apply the brakes with firm and steady pressure (not slamming though).

OK, granted, landing distance calculation is based on brakes (applied at maximum) and spoilers. Folks, this is for test flying, not line flying. Except for Midway and Pensacola, we normally fly into runways that are way longer than needed for landing. A smooth takeoff, landing, and rollout are what the passengers notice the most. Trying to make the first turnoff in a jet airplane may impress yourself, but doesn't impress the paying passenger.

OK, I'm open to comment. I can go on about derotaion and spoilers, but that's for another day.

Some of you who have been at Comair for any amount of time may recognize me by my initials. I may have even been your sim instructor. If so, I still love you guys/gals. Cya.

 

[XLR8]

What a GREAT post! I fly a CRJ and have seen way too many guys slamming on the brakes just to make a turn-off.

Anyway, I have a question to GCD (and whoever else cares to chime in). What is your opinion on pulling the reversers out, and getting them spooled up while the nosewheel is still in the air? I've seen it done on DC-9, MD-80, CRJ, etc.

My personal opinion is that it's a blast......yeah, it's kind of hot-dogging a little but I can't think of any safety concerns that make it dangerous. Besides you can always drop the nose quick if you have too. Opinions would be greatly appreciated!

Fly Safe!

 

[cl-65link]

It's called "aerodynamic braking" and it works as well on the CRJ as on any other aircraft. The CRJ's "shopping cart" nose-wheel and strut are hardly designed to absorb the shock of a 3-point landing(or close to one). I always stess to FO's I fly with that the CRJ can be landed in this way, it just requires a little more work and finesse than some other aircraft. Hey, GCD I know who you are, I did some of your IOE here at Peeknuckle

 

[Beechnut]

My opinion is it is bad form due to the fact that the engines may not spool up at the same rate in reverse. With the nose in the air, this may cause problems. Yeah, you MAY be able to get the nose down, but why ruin a good landing by slamming the nose down to recover the aircraft you just lost control of. Wait the extra half second and do it right.

My $.02

S.

 

[DC9stick]

What a GREAT post! I fly a CRJ and have seen way too many guys slamming on the brakes just to make a turn-off.

Anyway, I have a question to GCD (and whoever else cares to chime in). What is your opinion on pulling the reversers out, and getting them spooled up while the nosewheel is still in the air? I've seen it done on DC-9, MD-80, CRJ, etc.

My personal opinion is that it's a blast......yeah, it's kind of hot-dogging a little but I can't think of any safety concerns that make it dangerous. Besides you can always drop the nose quick if you have too. Opinions would be greatly appreciated!

Fly Safe!

It's Ok in a DC9 to deploy the reverse with the nose wheel off the ground then spool reverse after nose wheel touchdown to eliminate the before discussed directional control problems.

The MD-80 is another story as the reverse buckets are large enough to drag on the ground if the nose is not in a downward
motion during deployment. Our company procedure is nose on the ground before deployment.

 

[h25b]

Though I don't fly CRJ'S, I have ridden in the back as a paying passenger enough to notice exactly what this guys saying...

I've seen the premature braking thing going on when I know there's plenty of runway left when we turned off... He's right about brake effectiveness also.

The way I look at it... Every time you do that sort of thing, (i.e. engine spool-up, scortching the brakes, etc...) your looking to cause someone to have a bad day when they need the brakes to work well and they don't

 

[2000flyer]

The MD-80 is another story as the reverse buckets are large enough to drag on the ground if the nose is not in a downward
motion during deployment. Our company procedure is nose on the ground before deployment.

I remember reading after the MD80 came out that an airline, Peoples Express if I remember correctly, lost two lower buckets after they deployed the TRs without having the nose on the ground.

While it's not an airline, on the Falcon 2000, you can't deploy the TRs without the nose on the ground. There is a prox switch on the nose gear that has to be made in order for the TRs to deploy. On the Citation Ultra, deployment of the TRs before the nose is on the ground may result in an "unwanted" sudden pitch up.

2000Flyer

 

[Stiffler]

I've seen the premature braking thing going on when I know there's plenty of runway left when we turned off... He's right about brake effectiveness also.

The way I look at it... Every time you do that sort of thing, (i.e. engine spool-up, scortching the brakes, etc...) your looking to cause someone to have a bad day when they need the brakes to work well and they don't

You might have seen the "premature braking thing" happen...from the back as you stated. In defense of the unsuspecting flight crew...how do you know they were not told by ATC to expedite off the runway because of the 777 breathing down their neck, or the crosswind runway traffic waiting to take-off, or somebody is crossing the runway downfield without clearance? That whole riding in the back, and I'm a pilot so I know what's going on up front idea is great when you're talking to that hot passenger next to you, but doesn't mean you're aware of the situation at hand. "They slammed on the brakes and dog gone it if it wasn't uncomfortable!" Yeah? Maybe they just stopped the aircraft from hitting something, and in turn saved your judgmental a$s.
As for looking to cause someone a bad day when they need the brakes...I say we never use the brakes. Who knows? Somewhere, sometime, somehow, maybe somebody is going to need the maximum brake effectiveness. So to help these guys out, let's not ever use brakes. I mean after all, we want the most brakes we can get in an emergency. I sure wish maintenance would inspect those things every once and a while! Golly that would be swell if they would! I guess it's too bad the brakes on airplanes were never meant to be used (except in the event of an emergency) or replaced. What were those designers thinking?

 

[skydiverdriver]

The items that stop the CRJ are the brakes, spoilers and the thrust reversers, in that order. There is no such thing as premature braking, and aerodynamic braking is minimal on a jet. The best way to stop the aircraft is to put the nosewheel down and apply the brakes, and get the reversers out as soon as they will deploy. Waiting on the brakes makes as much sense as an intersection takeoff. The brakes are steel, and made to be used. Brake wear is minimal even if you use them immediately, and I never get them hot enough that it's a problem.

 

[skydiverdriver]

So,
You are saying that the aero braking guys know what they are doing? I once had a captain say that when we did a zero flap landing on a short runway. He said, darn, I should have used aerodynamic braking! I said, why, so the landing roll could be longer? When you keep the nose in the air, doesn't it reduce the effectiveness of the spoilers? Perhaps the flaps are at a larger angle to the wind, but not enough to make a difference. The main reason for the spoilers is to put weight on the wheels so that the brakes are more effective. The braking they provide by catching the wind is minimal. Same thing with the flaps. They are mainly out there to allow a lower landing speed so that the brakes are more effective. The best way to stop a jet is judicious use of the brakes.

 

[Beechnut]

Okay, thanks for the opinion, here's another perspective. The airline I work for has NO training or procedures for the use of aerodynamic braking. Our procedure strictly state the reverserse are to be used when the aircraft lands down to 80 knots. The reverses are to be reduced and at idle by 60 knots and the use of brakes will be introduced then. This is in writing, this is how they want it done.

You mentioned the demonstration you saw where the TR's were open without a spooled engine. The orginal mentioning of the technique spoke of the engines spooled. There is a difference.

I haven't ever flown a Challenger. Have you done this technique in a CRJ? Sounds like we're talking about two different aircraft.

Nice distinction between the Aviatior and the Drivers. Me being the company man, I'm probably just a driver.

S.

 

[cl-65link]

Allowing an airplane to roll long at the airport I primarily fly out of(MSP) will make you absolutely no friends in the tower and very few waiting in line on the ground. MSP has only two primary parallel runways and are in constant use for both arrivals and departures, unless you are there at 2a.m. And yes I know the runway is yours(all of it, if you need it).

 

[Broke in CVG]

We had an ops note re-iterating the the FSM procedure was to wait until the nose wheel was down before deploying the TRs. This "reminder" was a direct result of an incident. Empty plane (ferry flight) with an aft CG.... touchdown nose high and popped the TRs immediately and had a tail strike. I am not saying that I have never seen it done safely, but there is a reason why the FSM lays it out the way it does and this is one example of what CAN happen.

 

[ReportCanoa]

It is BAD BAD form to use so called "aerodynamic braking" with this aero. It is thought by investigators that this MAY cause unusual stress on the main gear and could lead to complete failure of the main beam. It has happened to one north american operator, and more than once across the pond. Eddy current tests have been run at several airlines and found an unusual state of the alloy. Newer CRJ's are equipped with a more substantial main gear...

 

[GCD]

Some very good replies.

I agree, you won't make friends in MSP by rolling out long, but on the other hand, there is reasonalbe landing distance to preclude the slamma-jamma. BTW- I had a good time in IOE.

As far as aerodynamic braking... well, I said derotation and spoilers was for another day...well, today is another day.

In landing a jet airplane, getting the nose down (derotation), as quickly as can be safely done (without damaging the nose gear), is very important. By getting the nose down, the center of mass (airplane's weight) is shifted from behind the main landing gear to over the mains, thus allowing for more friction to be applied to the tires for tracking and braking. The spoilers also become more effective with the nose on the ground. I know, it looks cool to ride with the nose in the air, but it ain't. When you see the long airplanes (B747, 757, 767, MD80) look like their nose is in the air forever, they are actually trying to derotate as quickly as can be done safely in that airplane. It just takes longer to get the nose down in a B747 than it does in a CRJ. If you ever get the chance to see the Boeing Company Derotation tape, do so. It will open your eyes.

My friend above stated that the CRJ's nose gear is like a shopping cart wheel. He's not far from wrong about that. The derotation in the CRJ, as in every airplane, should be done with finesse. The Boeing tape emphasizes that.

Deploying thrust reverse in the derotaion in a high bypass engine airplane is acceptable, depending on the airplane. The high bypass engine doesn't have "buckets" to strike the ground. I know that the B737-200 and MD80 can get a bottom bucket strike on the ground if the reverse is deployed while the nose is still in the air. Coming out of the B747 into the B737, I told the IOE Check Airman to slap my hands if I reached for the T/R before the nose was on the ground. He did once or twice.

I know about the Comair incident. I don't think it was "caused" by deploying reverse thrust with the nose in the air, but I think I know why the FSM wording was changed. It was to get you guys to get the nose on the ground.

Asymmetric thrust in reverse is a concern. On a dry runway, it is managable, as one post above indicated. However, on a slippery runway, I wouldn't go directly into the stops, as on a dry runway, until symmetric spoolup is assured, but maximizing reverse thrust on a slippery runway is still more effective at high speeds than brakes.

Also, remember, and never forget (as my friend said above), that you own the runway when you are on it. Trying help ATC is good, within reason, but it's not your job to fix their mistakes. There is no good reason to risk damage to your airplane just because tower goofed up and put one too close behind you.

 

[h25b]

Sorry to offend you "stiffler", that certainly wasn't my attention. My apologies...

I guess since I mentioned noticing it in the back, that was offensive... So I guess I should mention I used to see it up front also, when I know what the situation was.

As for trying to impress the hot passenger next to me, she was my wife.... (we stopped trying to impress each other years ago
)

And also, If I had a dime for every time I wasn't popular with ATC.... Well, you know the story... Try and remember the whole point of the forum "Stiff", it's informative discussion... Most people, including myself, don't jump in unless we have first hand operational experience on the topic. I think most people are missing "GCD" 's point. That is, when operational conditions allow, I little extra technique, thought, and awareness can make the passengers experience and the aircraft maintenance a little more enjoyable. The latter by the way contributes to the bottom line which, combined with the earlier pays YOUR salary.

There might be a day in the future, like me, that you end up having to be in the corporate world when frightening the wrong passenger can cost you your job or at the very least a regular passenger's confidence.

That's all, again my apologies...

 

[freightdogfred]

Takeoff thrust setting - There are some very good reasons why your FSM or FCOM says to advance the thrust to 70% N1, stabilize, then set takeoff thrust. The stabilization at 70% N1 is to allow for symmetric spool up. Both engines may spool up to 70% N1 at a different rate, but once stabilized at 70%, it is more likely they will spool to takeoff thrust more evenly. Also, by allowing the engines to stabilize at 70% N1, you are checking two other things, proper airflow through the compressor and that N1 is speed controlled to avoid an overspeed when setting takeoff thrust. Setting takeoff thrust from idle is really poor technique and even causes impulse stress to the turbine blades, causing a creep in the blades and eventually failure of the turbine blades, if done very many times.
.

While setting 70% is good technique to ensure symmetrical and stable engine operation, it will do nothing to eliminate turbine bucket "creep" or "stretch". This is a function of repetitive heating /cooling of the metal, and until you see ceramic turbines, you won't stop it. If you wanted to reduce "creep" and extend turbine life, you would be advised to employ a similar technique at the top of descent, reducing power in increments, vs. going from cruise power to idle. I don't fly the CRJ, but most FMC'S calculate profiles on fuel savings so if your a/c has autothrottles, ther's not a lot you can do.

 

[GCD]

Freightdogfred,

You make a very good point about TOD thrust reduction. However, I was talking about impluse stress creep by going from idle to takeof power. It's from GE, not me. It's something to do with going from 400'C to over 800'C in a couple of seconds. The turbine blades are exposed to rapid heating and rapid centrifugal force simultaneously. While it may not hurt the engine if done a few times, over a period of events, the engine life is reduced.

Also, I know the Comair FSM addresses this, but I know a particular FCOM that does not. That is, after start, the CF34 engine must be at idle thrust for two minutes prior to takeof thrust being applied. That also from GE.

As for those of you who think there is no such thing as premature braking - I didn't make those figures up. The figures came from airplane and brake manufacturer test results. However, you fly your airplane the way you want to. I am only offering my two cents worth of advice. Take it or leave it. I am always open to advice, myself.

Also, I am not saying to not use the brakes, as someone eluded. I advocate, as the brake manufacturers do, to make a firm steady application at 80 knots. A brake, by definition, is a machine or device that converts kinetic energy into heat, then dissapates the heat into the atmosphere. Therefore a single firm application produces less heat than a prolonged application, especially a prolonged, light application, as in taxiing.

Beechnut, your company has it right!

 

[ClearRight]

I'll chime in on the incentive to wait until the nose is on the ground before revving up the reverse thrust. I've got about 700 hours in the RJ and until last week I'd frequently do the "shuttle landing"- mains first, fly the nose while bringing the reverse levers up. Last week I landed fairly light so the nose was rather high, I held it up and added reverse thrust. It wasn't immediate, but I ran out of elevator with the nose wheel still in the air. WHAM. I'll not do that again. From now on, it's nose down, THEN bring in the reverse- just like I was taught!

 

[HighSpeed]

What about heating the brakes??

Good thread on the use of reverse thrust, but I was told that heating the brakes by using them more during landing will extend the life of the brakes. ie.) the carriers in Europe that do not use reverse thrust at all, yet enjoy longer brake life than thier U.S. counterparts because they have to stop using brakes only.... If revrse thrust is used primarily, the brakes will not have "warmed up" and therefore will have excessive wear while "taxiing in" to the gate.....

 

[logolight]

As an RJ fo, I've seen captains do everything from deploying the TR's with the nose in the air to not using the TR's at all. I also know from training that with just a little extra control input, the RJ will handel a single engine reverser with little adverse controlability. As far as the stories of the nose slamming onto the runway, I flew with a captain once who would actually increased the pitch of the aircraft by about 3 degrees after the mains touched down and he never crunched the nose onto the runway. One last comment, I have never seen anybody nor myself "derotate" the nose to the point of using full aft elevator. But under certain weights, I have seen the RJ's nose touch down at amazingly low air speeds.




Snooch to the Nooch!

 

[CatYaaak]

[But under certain weights, I have seen the RJ's nose touch down at amazingly low air speeds.[/B]

Having an amazingly low airspeed means your rudder effectiveness is deteriorating rapidly, and since the nosewheel isn't on the ground yet, no nosewheel steering. Weathervaning tendency applies to rollout just as it does on takeoff.

Nose high means poor forward visibility, and increasing the pitch 3 degrees (like the captain you mentioned) means it's even poorer. If you DO have to suddenly apply heaving braking (runway incursion, deer, whatever) and have to get it stopped right NOW, the nose will crunch to the runway anyway.

Using this technique, you may as well toss the performance book's numbers for Landing Distance and LFL out the window, since there is no "Look I'm aerodynamically braking like an F-15" chart to be found anywhere.

Related to this last point as it applies to career insurance, remember that the CRJ has a good Flight Data Recorder, and if for some reason you end up in the weeds beside the runway or off the end, it will tell the story of your "technique" to any interested parties. Don't worry about this however, if your FSM or FOM calls this a normal rollout technique. Correct me if I'm wrong, but I doubt that it does.

It can be uncomomfortable for passengers, especially white knucklers.

IMO, the disadvantages far outweigh any imagined advantages or "pilot appeal" factor.

 

[GCD]

HighSpeed,

You are partly correct, but not completely.

Heating the brakes moderately, as described above with firm steady pressure at 80 knots until a safe taxi speed, is the optimum heat absorption for the brakes. Applying brakes excessively to produce excessive heat acts the opposite. A hot brake cannot absorb heat sufficiently to make a safe stop. That's why there are quick turnaround charts for minimum turnaround time after a landing.

I have worked around Lufthansa, and I am pretty certain that they use reverse thrust. I could be wrong. When I worked for JAL, the Japanese couldn't figure out why the Gaijin (Americans) were landing with cooler brakes than the Japanese pilots. Well, it was because we followed the above procedure, and the Japanese always use Autobrakes in Medium. The company always used cooling fans on the brakes after a Japanese crew made a landing. I used Medium once in a snow storm. It was a lot more braking than I was comfortable with. I never used Max in the real airplane, only in the sim, but that was impressive. The problem is, you have to go to a hazard spot to allow the CFR to watch for an ensuing wheel fire.

Sounds like some horror stories coming forward from keeping the nose up too long. Remember, mains down, nose down, reverse, brakes.

 

[SkyWestCRJPilot]

This is a great thread. My personal technique is to gently lower the nose wheel soon after touchdown. I've flown with pilots who let it slam down right after the mains, and I've flown with ones who like to hold it up and let it fall after the elevator loses its effectiveness. I don't like either of those methods personally. I liken landing the CRJ to landing an airplane twice, first on the mains softly, and next lowering the nose softly. I flown with a lot of guys who just grease on the mains and then forget the nose is still flying and let it just slam down hard. It kind of ruins a good landing not to mention the other reasons others have previously stated for not holding the nose up too long.

I don't even touch the brakes till below 80 knots and then just barely so that when I reduce the reverses the airplane won't lurch forward. Most of the time there always is enough runway. There have been a few times when I've gotten on the brakes early, but that was because I screwed up and floated way down the runway using up precious stopping distance.

 

[logolight]

I think the problem is that there's no performance data or standard training technique that I know of that supports the correct way to rollout an RJ except for the use of the TR's. Once the mains are on the ground, lowering the nose down to the runway correctly is a grey area safety wise. The slow speeds that I'm talking about are well above the low speed barber pole where there is still plenty of rudder effectivenes. I've never landed at an angle so high that I had poor foward visibility, and the breaking margins for incursions etc. are marginal since the nose is only inches off the ground.
Where the problem lies is when tower tells you to "keep the speed up and roll to the end" at which point you are at a high taxi speed and not only cutting down on the reaction time for things like incursions, but you're also running out of available pavement to stop if you suddenly lose your breaks. I do agree with you CatYaak that there are all kinds of possible dangerous situations during the takeoff and landing roll. Thats what this discussion is about.

In my opinion, land the plane, slow it down, and get it under control.



Snooch to the Nooch!

 

[freightdogfred]

Interesting thread.....It's seems more on technique than what's "correct". I don't fly RJ's, but I jumpseated in a few, pre-911. We were halfway down the Macey arrival into ATL before I figured out where the airspeed indication was. It did'nt seem to have a high ref speed, so if the profile was flown correctly I think a good pilot could make the second high-speed on 8R without using brakes or reverse.

Runway analysis is predicated on max braking, no reverse. If you are going into a tight (short) strip, the sooner you get the nosewheel on the ground and apply brakes, the better your chances for stopping on the runway become. Runway clutter merely exacerbates the situation. Reverse thrust is a bonus, and is not considered in the data. Aerodynamic braking, three point landings, no spoilers,etc. are technique, employed when actually stopping distance is not a factor.

I used to fly DC-3's with Goodyear disc brakes. (They would fade rapidly with heat.) One guy I flew with would push forward on the yoke after touchdown, with the tailwheel still in the air. He called it "Aerodynamic braking". It took all day to get that seat cushion out of my ass.

It's common sense- if you need the brakes, use them. The slower the A/C is going prior to application, the less they will wear. This applys to the space shuttle or a C-150.

 

[GCD]

FDfred,

If you were j/s in a Canadair RJ, it was a very light one.

Typically, Vref + factor = 140's for a target speed on final.

The CRJ's final approach speed is similar to the B747's. The big difference is, that I can vector around slower in a 747 than I would feel safe to do in the CRJ. Especially in icing conditions.

The lumbering giant has leading edge flaps and trailing edge flaps that create a huge wing surface. The Canadart has a hard, thin wing without LE devices. Thus the 3' nose low attitude on final.

That is one of the resons I started this tread. The Canadart has a very fast fence speed, and puts high demands on the airplane's stopping systems.

I do agree with you, FDfred, the slower you are when you apply the brakes, the longer they will last.

 

[abev107]

this is a great thread! I enjoy it when you folks share a philosphical discussion on technique, etc...