CRJ flight - what the heck was this event?

Sounds like an inadvertant deployment of the spoilers.

 

There are plenty of reasons to deploy the spoilers-- usually because we're high and fast.

An old joke involves a controller asking a pilot to cross a fix at an altitude that would require too steep a descent. The pilot refuses, and the controller asks "Don't you have spoilers on that thing?"

The pilot's response-- "Yes, and they're for my mistakes, not yours."

In most jets, I tried not to use the spoilers because they caused a rumble and the passengers noticed (or so I thought, anyway). It was always a point of pride. In my early days, I used to fly with a Captain who put the spoilers out on almost every descent, and it used to drive me crazy!

Your situation sounds like poor technique-- while I have never flown a CRJ, I would hope there is a way to put the spoilers out without it feeling that abrupt.

 

The person flying the plane deployed them to fast. The faster you pull the handle the faster the spoilers go up. It can feel very abrupt in the back and it also forces the wings down.

 

Don, I could never imagine a pilot purposely deploying spoilers at anything near cruise speed. I was on a 720-B test flight when they made a " jet penetration" rapid emergency descent. The pilot told everyone to strap in and to expect a rough ride. After dumping the main gear and the nose he deployed spoilers and the bashing and banging around that we got was impressive. The turbulence from the spoilers had the horizontal tail doing a wild dance and the shaking loosened up several overhead panels that dropped to the floor. That airplane dropped like the proverbial brick. Leveling off he said," Wasn't that fun?" This isn't something that you do with passengers aboard, even a little bit, huh Jedi?

 

I disagree with that, we use the spoilers at cruise speeds (.77-.80 mach) quite often if we have to make a fix at a certain altitude. There is not much difference between what you feel at slower speeds. The trick is in how fast you deploy or retract them, that is where the abrupt "shock" comes from and can scare the crap out of people. Now if you drop the gear at those speeds you are talking serious noise and vibration, makes you think the whole plane is coming apart.

 

It depends a lot on the airframe. I can't think of any jets I have flown which had a speed limitation on spoilers (other than the Learjet limitation not to deploy them above Vmo/Mmo), but deploying them at high speeds is best avoided.

As I'm sure you know, spoilers on jets really serve two purposes-- emergency descent, and adding drag to keep the engines spooled up while descending in icing conditions. Either of those purposes can require a cruise speed deployment.

In this case, it really sounds like bad technique to me-- even if they were needed to make a crossing restriction, I'm sure they could have been deployed smoothly.

Jerry is absolutely right about the gear. I once had to do a gear down ferry flight in a Falcon 50 lasting around 3 hours, and the noise and vibration just about wore me out!

 

I would agree that deploying spoilers at cruise speeds is routine. There was no limitation on spoiler deployment on the CRJ, or Airbus for that matter. I am forced to use full speedbrakes on the airbus at 340 indicated to make crossing restrictions when controlers leave you too high due to traffic.

Donv brings up an interesting point that certain pilots make about spoiler use. I have heard the same thing from captains on the CRJ that if you use spoilers you are a bad pilot or poor planning or whatever. No offense, but it always seemed to me that those guys were big on being "superpilots" and their ego was usually too big for the cockpit. The simple fact of the matter is that the airplane manufacturers installed a lever so you can manually deploy spoilers/speedbrakes in flight for a reason. They are there to be used. Sure you can fly the airplane without them if you want to make controllers' jobs more difficult by desending earlier than they would like but some airplanes just don't go down and slow down at the same time without the speedbrakes (the A320 for one). And I have never had a captain on the the Airbus say that speedbrakes should not be used or about being a poor pilot if you do. It's just the case that they are needed on nearly every flight because the Airbus is such a clean aircraft.

I would agree that it was most likely bad technique by extending them too fast on your flight.

 

Once, while descending eastbound in a United 767-200 with eventual destination La Guardia, we had to penetrate a line of clouds over New Jersey which had some pretty heavy turbulence. (You know that's coming when the flight crew asks the flight attendants to stow their carts, sit down and strap themselves in!)

For about 8 minutes we were doing the rock and roll while passing thru the clouds; all you could see outside was a uniform grey. I was glad that the 767 was built stoutly (with some parts in it that I had designed myself!), but even as a fairly frequent flier, I found myself almost digging my fingernails into the armrests. And I was sitting near the aircraft CG, which supposedly gives a smoother ride. With every significant jolt, you could hear an audible "Oh!" throughout the cabin.

Well, the reason I say this is because for the entire 8 minutes, the spoilers were deployed. I can't imagine that we had that much descending to do, so there must have been another reason.

 

Its possible the crew stayed high longer to get around some cells or over a line then had to make a long rapid decent as opposed to a normal step down decent. And as Don said if they had the "carb heat" on, which usually affects a 20% increase in engine speed, the use of spoilers would have been required to keep the airspeed from redlining.

 

My opinion on spoiler use is that they are there if you need them, but shouldn't be a part of routine operations most of the time. Descending in icing? Absolutely. Landing straight in at Aspen? Sure. Descending into Wichita on a clear day? Really not needed.

And, if you use them all the time, what happens when you're still too high for your crossing and the spoilers are already out?

I've never flown an A320, so maybe it needs spoilers more than other aircraft I have flown. In any event, it's all technique-- we all have our personal peeves, so nothing to take too seriously.

Maybe we should start talking about what we do when we hear someone transmitting on 121.5? ("You're on GUARD!!!!")

 

Of course none of us, particularly "I", have never dropped the gear on final and heard "spoilers!" from CAS then the proverbial.........."S*&T"

 

I agree, there is a lot of technique involved. I believe in a MD80 you can extend slats and maybe even the first flap at 270 indicated... On an A320 slats can't come out until 220, and no flaps until 190. It is simply a nearly everyday occurance to use the speed brakes. Going into O'hare, they want you at 250 to intercept the glideslope at 8000' or even at 220 there is no way to slow the plane down to get it configured without the use of speed brakes, unless you want to drag the gear for 20 miles.

As for crossing restrictions, you have to be on top of it and if the controlers hold you up you have to tell them that the restriction is not going to happen. And I have personally had to drop the gear at 11,000 feet in Detroit in order to try to comply with what the controllers wanted. Of course if you can avoid it, the ride is better without the brakes, but it's required quite often on the 320. When I fly on other carriers I notice that the spoilers are hardly used on 73s and MD80s but they seem to be used much more often on the 75s and 320s.

And it is quite funny the different things we get wrapped around the axle about, but we wouldn't be pilots if we weren't *****ing about something now would we?

 

Those small Bombardier's are pretty light - very reactive control surfaces. More of a jerky-liner than a dream-liner.

 

The 70 seater was ok to fly but the 50 seater is a crap-liner.

 

I fly the 757/767, and agree with all the previous comments...I would just add that spoilers come in most handy when you're heavy and have to slow that inertia-make a speed reduction-while descending. If I alowed the 767 to slow and descend naturally at its own "Isaac Newton rate" going into a busy airport like Heathrow or Newark, aircraft of dissimilar size, weight, etc., would have to be sequenced huge distances apart. Not to mention that the controllers would go crazy. Just not something that's very practical. Yes, in the Air Traffic Control of yester-year, when the traffic was'nt so saturated, the use of spoilers could have been reduced to merely correct "optimistic planning". But, for better or worse, in the crowded skies today it's standard and necessary practice. That being said, there is a smooth and a not-so-smooth technique that an individual may use in their deployment.

 

Not a pilot, but enjoy these...

My first thought reading Jedi's OP was that maybe 'someone' inadvertently pulled the spoilers without meaning to...

Is that possible or probable?



I've flown (as pax) in a lot of CRJ's and seen spoilers out many, many times. Usually fairly smooth. Only when descending for destination.

Can't imagine it being so abrupt that your forehead smacks the seat in front of you.

 

I'll assume it was just the speed brakes being deployed.

First question would be how far out from arrival where you??

Second, you can go to liveatc.com, go to archives - and listen to the arrival of your flight.
You'll hear who you were following and why you had to slow down.

If you have the flight number and date - I'll look it up for you.

I wouldn't be surprised if you had a Boeing 757 or another 'heavy' aircraft in front of you.

rob CYKZ

 

Nowhere near final...

He said he was a half hour out, still a cruise altitude.