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Help Me Settle An Argument Over Spoilers On CO  
User currently offlineRjpieces From , joined Dec 1969, posts, RR:
Posted (9 years 8 months 3 days 5 hours ago) and read 3317 times:

I posted a similar question in Tech Ops but in typical A.net fashion, the thread went in a million directions without the question being answered! So I will ask it here, and hopefully get a CO pilot to answer.

A friend says he flew into DCA on a Continental 73G and that when the aircraft landed, no spoilers were used. He says he has seen this several times at DCA on CO, on 735s and 73Gs.

So I was wondering if this is true. The Tech Ops thread has established that it IS possible to land without spoilers, given a long enough runway/right conditions. But does CO do this at DCA? Is it possible to do at DCA given the relatively short runways and above all, WHY would CO choose to do this. Any thoughts are appreciated.

Regards.

14 replies: All unread, jump to last
 
User currently offlineFlybyguy From United States of America, joined Jun 2004, 1801 posts, RR: 1
Reply 1, posted (9 years 8 months 3 days 4 hours ago) and read 3263 times:

Are you sure your friend knows what spoilers are? I think even on a decently long runway spoilers still deploy automatically as part of the aircrafts runway pre-programmed braking regimen.

A second theory could be the pilots neglected to ARM the spoilers in their landing checklist. I am not sure if there are FMS countermeasures if this happens, but if there isn't I suspect that maybe in frequent traffic vectoring in the DC area the pilots may have deployed the spoilers to control the aircraft's speed while in the air, but when retracting them failed to place the spoiler lever back into the ARMED position.




"Are you a pretender... or a thoroughbred?!" - Professor Matt Miller
User currently offlineLongbowPilot From United States of America, joined Jan 2005, 577 posts, RR: 3
Reply 2, posted (9 years 8 months 3 days 4 hours ago) and read 3250 times:
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Spoilers assist the pilots in breaking by A. breaking up the lift vector on the airfoils which doesn't allow the aircraft to pop back up off the runway. B. It forces the wings down on the wheels increasing the friction of tire to runway. Theoretically if the aircraft is light enough the spoilers aren't really required. The aircraft has quite an inventory of breaking power in the breaks. The only problem is if they fry'em up they have to wait for them to cool before they leave or risk having a magnesium grenade in each tire.



User currently offlineIAHERJ From United States of America, joined Jun 2001, 677 posts, RR: 7
Reply 3, posted (9 years 8 months 2 days 15 hours ago) and read 3127 times:

My guess would be that the crew forgot to arm the spoilers during the final approach (usually when the gear is lowered). I've done the same in CAK once on the 717 and it felt as if we were floating up and down on the landing gear struts. There is no real alarm to remind you on the 737 and some pilots intentionally neglect the arming of ground spoilers and manually deploy them in a softer manner on rollout to aid in "rolling" the aircraft on. DCA would not be a city for this kind of methodology. It was probably neglect by the crew who was under a high workload visually and manually having to fly the river visual and the captain just forgot to pull the handle and arm the ground spoilers.

IAHERJ




Actually flown: EMB-120 EMB-145 B717 B737 B757 B767
User currently offlineAA737-823 From United States of America, joined Mar 2000, 5824 posts, RR: 11
Reply 4, posted (9 years 8 months 2 days 13 hours ago) and read 3068 times:

It is possible that it happened, but really suspicious. I doubt your friend fully knows what spoilers are. He may think he knows, and when you explain it to him, he may claim to understand, but still.
I have NEVER been in an airliner that didn't deploy spoilers on landing. Arming the spoilers is part of the landing preparation checklist. The checklist is done more than once (as in, they verify its completion).
And, they would certainly notice a floaty feel about the airplane just after touchdown. Less air braking, and poor wheel braking traction, with the wings still near lift-producing speed.


User currently offlineBALandorLivery From UK - England, joined Jan 2005, 360 posts, RR: 1
Reply 5, posted (9 years 8 months 2 days 13 hours ago) and read 3026 times:

SPOILERS DEPLOY ON TOUCHDOWN AND THE 'KILL' THE LIFT ON THE WING.

THIS BASICALLY MAKES THE AIRCRAFT STICK TO THE GROUND (too put it simply).

ARMING THEM FOR AUTOMATIC DEPLOYMENT IS PART OF THE LANDING CHECKLIST ON MOST IF NOT ALL OF THE WORLDS AIRLINES, WHATEVER THE AIRCRAFT.

spoilers not being used is VERY unusual, I think your friend most likely does not know what spoilers are.

If you remember an AA overran the runway at Little Rock, part of the reason was that the spoilers weren't armed and did not deploy.

Hope this helped.


User currently offlineBpat777 From United States of America, joined Nov 1999, 417 posts, RR: 0
Reply 6, posted (9 years 8 months 2 days 13 hours ago) and read 2993 times:

Slightly off topic but do airliners have some type of warning system to alert pilots if flaps are not set for take off? If I'm not mistaken a NW MD-80 crashed on take off back in the 80's because the flight crew did not set the flaps.

User currently offlineBALandorLivery From UK - England, joined Jan 2005, 360 posts, RR: 1
Reply 7, posted (9 years 8 months 2 days 13 hours ago) and read 2981 times:

YES, THERE IS USUALLY A TAKEOFF CONFIGURATION WARNING HORN IN AIRCRAFT.

AS FOR THE NW MD80 THEY DIDNT HEAR IT I THINK


User currently offlineUsairways16bwi From United States of America, joined May 2004, 1004 posts, RR: 4
Reply 8, posted (9 years 8 months 2 days 12 hours ago) and read 2958 times:

Of the three main braking systems, ( wheel brakes, spoilers, and reverse thrust) spoilers provide the least braking of the plane. The reverse thrust and wheel brakes provide the most braking. But it is common for planes to land without reverse thrust, just wheel brakes. A lot of times when landing in ATL there is no reverse thrust. I don't think it will make that much difference if the spoilers aren't used on landing( as long as reverse thrust and wheel brakes are applied). Maybe the spoilers just give more stability when rolling out on landing, especially if its windy.

User currently offlineBALandorLivery From UK - England, joined Jan 2005, 360 posts, RR: 1
Reply 9, posted (9 years 8 months 2 days 12 hours ago) and read 2932 times:


Usairways16bwi:

The use of spoilers on touchdown is not to slow the plane down so much (brakes and reverse thrust do that as you said).

The spoilers are used to kill the lift and make the aircraft stick on to ground so to speak.

If spoilers were not used, a hard landing may result in the aircraft becoming airborn again.

Use of the spoilers make sure this does not happen because it kills the lift of the wing and therefore the aircraft will stay on the ground.


User currently offlineAirbus Lover From Malaysia, joined Apr 2000, 3248 posts, RR: 9
Reply 10, posted (9 years 8 months 2 days 12 hours ago) and read 2936 times:

When landing on 32L at KUL, many smaller aircraft such as the B734 does not deploy spoilers immediately and they hold the nose off the ground for longer, to cut down runway occupancy time because the runway is long and they don't want a long taxi... The terminal is just right after the turn-off at the very end of the runway. So it does happen from time to time esp when runway is long and pilots have clearance to take up the whole runway length for rollout to cut down taxi time.

User currently offlineRjpieces From , joined Dec 1969, posts, RR:
Reply 11, posted (9 years 8 months 2 days 11 hours ago) and read 2877 times:

Thanks for all the replies everyone. Can anyone talk about the feasibility of CO doing this at DCA?

User currently offlineOPNLguy From , joined Dec 1969, posts, RR:
Reply 12, posted (9 years 8 months 2 days 9 hours ago) and read 2779 times:

>>>Can anyone talk about the feasibility of CO doing this at DCA?

Personally, I think your friend may have confused thrust reversers with spoilers....

Under certain conditions, aircraft can be dispatched with inop reversers, The automatic function of spoilers can also be inop (meaning one has to deploy them manually versus automatic deployment upon touchdown), but (as has been said earlier) spoilers are needed to kill the lift and allow the weight of the aircraft to settle on the wheels for optimum braking. With water at each end of DCA's main runway, I find it difficult to believe that spoilers (more accurately, GROUND spoilers, wouldn't be used.


User currently offlineAA737-823 From United States of America, joined Mar 2000, 5824 posts, RR: 11
Reply 13, posted (9 years 8 months 2 days 8 hours ago) and read 2754 times:

Yeah, DCA's runways aren't exactly infinite. They're kinda short, IIRC.
A DC-10 has landed there in the past, but that was an emergency, and DC-10s were known for short (727 LaGuardia style) landings anyhow.

There IS a "misconfig" alarm to let pilots know that the aircraft is not configured properly for takeoff or landing. Typically, If speed exceeds a certain level without flaps, the horn sounds. Or, upon landing, if the gear is down and the flaps aren't out to a certain level, the horn will sound. The exception would be the Fokker aircraft- they take off without flaps all the time. Scared the poops out of me the first time I flew in one!

R


User currently offlineType-rated From United States of America, joined Sep 1999, 5036 posts, RR: 19
Reply 14, posted (9 years 8 months 1 day 18 hours ago) and read 2618 times:

Slightly off topic but do airliners have some type of warning system to alert pilots if flaps are not set for take off? If I'm not mistaken a NW MD-80 crashed on take off back in the 80's because the flight crew did not set the flaps.

On that incident aircraft, for some reason the crew had pulled the circuit breaker on the t/o configuration warning horn so it wouldn't sound:

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20001213X31759&key=1



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