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Type rated on A330, B747-400, B747, B757, B767, B737, B727. International Airline Pilot / Author / Speaker. Dedicated to giving the gift of wings to anyone following their dreams. Supporting Aviation Safety through training, writing, and inspiration.

Monday, November 8, 2010

Difference Between Airbus and Boeing: Speedbrakes

One of the greatest differences between Airbus and Boeing is the use of Speedbrakes.

Speedbrakes are used to increase drag. On the Boeing we're not supposed to use them in conjunction with flap extension. On the Airbus, flaps and speed brakes are a standard event.

When ATC keeps us high and fast in the Boeing, it's more of a challenge to get her down and slowed. If memory serves me correctly, the B757 presented the greatest challenge of all to slow down and go down. In the Boeing, if we needed speedbrakes-- that was to fix the "pilots" mistake. We should plan better. With the high level of traffic today, there are many approaches that all the planning in the world won't help if ATC is managing your speed and altitude-- fast and high.

On the Airbus A330 we can use speedbrakes with full flaps. System logic says we could use them all the way to landing if we wanted to, but landing with them is not recommended.

When speedbrakes are used, a SPEED BRK messages appears in the memo to inform the pilots they're extended. This message changes to Amber if the power is above idle for more than 50 seconds. Why? We don't want power and speedbrakes. The reason we're using them is to increase drag. If our airplane is increasing thrust, she's telling us that she doesn't want drag -- she needs power.

If we don't listen to her and the 50-second memo remains illuminated for more than 30 seconds, OR we are below 800 feet AGL more than 5 seconds-- a new message appears:

FCTL SPD BRK STILL OUT

Either of these situations is not good. We're not managing our plane correctly. We've forgotten the speedbrakes are out. We're in an unstabilized approach close to the ground.

Fact:

We know that ATC will keep us high and fast at certain airports. On the Airbus we have tools available, including speedbrakes with gear and flaps extended, to slow her down.

Recommendation:
  • If you're using speedbrakes during approach, a busy time, keep your hand on the lever so you don't forget to retract them.
  • Anytime you're on approach and hear "Terrain! Terrain!" and the aircraft is not performing as it should your hand should automatically go to the speedbrake lever and make sure it's forward. You may be too busy looking outside to notice the memo message.
  • Anytime you perform a go-around due to an unstabilized approach, confirm your speedbrakes are forward. (You more than likely were using them.)
The crash in Cali Columbia, December 20, 1995 might have been avoided had they realized they're speedbrakes were extended during their go-around. Situational Awareness was a huge factor in getting them into that situation, but the fact they were unaware their speedbrakes were extended during the go, was the final blow.

Know your plane. Follow procedures. Establish habit patterns of safety.

Enjoy the Journey~

Karlene

12 comments:

  1. Why can they not be used in the boeing with the flaps down? Manufacturer liablilty?
    Dan

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  2. Dan, operationally speaking you could use them-- Boeing procedures just don't condone it. It's similar to putting a big hole in the wing-- She comes down really fast. We played around in the simulator in the B727 once and exceeded 6000 feet--The limit of the vertical speed indicator.

    On the line, at two of my previous airlines, I've witnessed a few pilots use both speedbrakes and flaps on the B747. She worked fine, just came down really fast. I don't think the airplane was designed for the added stress-- or could be a liability issue because of the excessive sink rate at low altitudes.

    Boeing people--- any answers?

    Thanks for the great question Dan!

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  3. Unless I've been FB ENTIRELY too much lately, we can, and do, use them down to, and including 20 degrees (approach) flaps on the 757/767, and even then it still doesn't come down as well as the MD80 did with 23 degrees flaps alone, primarily, I think, because of the difference in max airpeeds at those settings. Flap speeds are ludicrously low on the Boeings compared to the MD, which can give the misguided impression that they're more aerodynamically "slick," when in fact they're just apparently more structurally fragile. It's funny that the speeds are lower with Boeing's jackscrew actuator mechanisms versus the MD-80's far less mechanically-advantaged hydraulic piston actuators.

    Can you tell I miss the MD? It's a tank!

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  4. Hi Nate! Really? Wow... that's new to me. But it's been years on the 757/767. We weren't supposed to on the 727, 747... and I know not on the 777 either. I didn't think we were allowed on the 757 either. Are your 757/767 reconfigured with the winglets? Maybe that's the difference. Want homework while you're lusting after the MD? Find out! :)

    Side note...Do you think this fascination with the MD is a "first" love sort of obsession?

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  5. Getting Fifi to go down AND slow down is an exercise in frustration, isn't it?? I've learned that it's best to try and keep my speed up and slow down once I'm within 1000 ft of my altitude. In ACY we have what we call the "ACY visual," 250 kts, get down to 1700 ft and press for managed speed 5 miles from the FAF (give or take for wind conditions). Amazingly she'll be on speed perfectly! I didn't believe it the first time I saw it :)

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  6. Mikel, that is the best way for sure.. go down, then slow down. 250 knots, 1700 ft and managed speed 5 miles. I'm going to put that into my took kit! Thanks for the great comment!

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  7. Ok, you talked me into (ugh - I loath the very word) RESEARCH, and, as uncomfortable as it makes me, my disagreement light's still illuminated.

    I only plumbed the 727 and have only jumpseated on a 747 once, but our manuals give no restrictions on the use of speed brakes on a 757 or 767 without winglets, unless we want a landing flap setting (25 or 30) or are lower than 800 AGL, at which time one of Boeing's patented Most Annoying Sounds in the World comes on to remind us that's verboten - I'm guessing because of the pronounced sink rates it would cause. If we're flying a winglette (cute, huh?), we're instructed not to overrule some bloody Airbus-like load-relief computer that seeks to keep us from extending them more than 50% if we're heavy AND fast, but otherwise, we have no restrictions with winglets, either. Hard to believe, but could it be a GE vs. Rolls Royce thing?

    On the MD, now, it was a different story. On that one, we could NOT have speed brakes and any flaps, just half-slats (280 knots max). Since the boards did more to make public the fact that you'd failed Descent Planning than help you out of your mess, I tried hard to rarely use them. With half slats and flaps 11 available at 280, flaps 15 and full slats available at 240, and flaps 23 available at 220, you could get about a ten degree down bubble and about 3000 feet a minute out of her all the way down, once you got slowed. 'Course using flaps and slats to make a crossing restriction wouldn't exactly be ATP-level flying.

    Boeing's speeds on the 757/767 start at 240/250 for half slats (flaps 1, they call it) and go down from there, so it's definitely not a slam dunker. I see fellow pilots use the boards almost every descent, before, during, and sometimes even after dropping some flaps.

    As for first loves, I'll say this. I flew the 757 and 767 before I flew the MD - and I liked them, but it wasn't love. Every airplane has an aerodynamic personality, and the 737, 757, and 767 all remind me of most Cessnas, which is to say, they have all the nuance and unpredictability of a Three's Company rerun.

    Because of all the bad press it got from other pilots (like lots of other "idiosyncratic" airplanes like the B-26, Cardinal, Yankee, Metroliner, MU-2, etc.), I thought I'd hate the MD-80, until I got to know it and saw how much it was like the Metroliner: heavily wing-loaded, tough, moody, mysterious, maybe even unforgiving - in many ways like the Yankee, which was, after all, as you so accurately perceived, my true first love.

    I like planes that do their job well, but I only love the ones that make me work to look good and never let me get too cocky.

    Just the way I rotate...

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  8. There's nothing that says you can't use speedbrakes with flaps on the 747-400. The 747-400 Flight Crew Training Manual says using speedbrakes beyond flaps 5 causes buffeting, but does not specifically prohibit it.

    The AAL Cali accident was during descent on approach, not go-around. They transposed a couple letters for a waypoint on the LEGS page and turned towards a mountain. I think the investigation concluded that had they retracted the speedbrakes during the GPWS escape maneuver, they would've cleared the ridge line. As it was, they just barely hit the top of the ridge.

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  9. Wreckless Pilot, thanks for your comment. Which company's 744 Flight Crew Training manual say's you can use speedbrakes and flaps?

    Perhaps all 8 airlines I've worked with must have made that "no-flaps with speedbrakes" a company mandate-- and not a Boeing mandate. Interesting. I'm going to do further research for sure.

    The AA crash in Cali did happen on the go. Not on the approach. Lack of situational awareness got them into trouble as they dove for their approach. But when they were getting out of there they forgot their speedbrakes were out and hit the treetops. The escape maneuver is not an approach maneuver, but--- a get out of there maneuver. Bottom line-- they couldn't get out because they didn't retract their speedbrakes.

    Question: Does "barely hitting" the top of the trees make a crash any less horrendous?

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  10. Thanks Nate for your research! I'm wondering if it were a company issue. My nephew is one of the big wigs at Boeing... I'm going to have to shoot him a message on this. I think you're right about the high descent rates for sure.
    Also... Boeing landing like a Cessna? I always said that about the 747. You felt like you were going as slow as a Cessna too, 5o feet in the air. The 727... she was a different kind of animal on landing.
    Thanks for your insight on this!
    It has been years-- okay 20+ since I played in the B757. I'm taking your word for it!

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  11. It's the Boeing FCTM. Airlines may impose their own restrictions. It says it should be avoided beyond flaps 5, but doesn't say "prohibited". It also says use of boards with flaps may result in high sink rates, and the speedbrakes should be retracted by 1000' AGL.

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  12. Thanks Wreckless pilot for the info! I haven't used a "Boeing" FCTM for a long time. Just the airline manuals. I suspect it was company procedure mandate. In the original Boeing emergency checklist for rapid depressurization, they didn't even have "put your oxygen masks on." Interesting thought there. Also, I know the Boeing FCTM changes their procedures more than most women change their minds. One year while instructing on the 737, we had "5" changes come through. All driven by the cadets in Asia, low flight time and excessive growth in China.
    Interesting. Thanks again for your comments! Love them.

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