Spoilers, no spoilers?

An Air Canada DC-8 crashed in 1970 because spoilers were deployed
before landing, which "by the book" is a definite no-no (cf. Air
Canada 621 disaster). How come the first officer (with over 5500 hrs
with that type of aircraft) made such a decision to deploy spoilers
while still in the air? What else, when full flaps and idle power
aren't enough, can a pilot use to handle a too high/too fast final
approach if not deploy spoilers?

As a side question, what is the functional difference between spoilers
and airbrakes?

Hi,

In article ,
wrote:
As a side question, what is the functional difference between spoilers
and airbrakes?

Just read that section of the book for my PPL exam. I *think* that spoilers
can be used differentially for roll control, whereas speedbrakes both pop up
together so can't control roll.

But I'm probably wrong

Andy

As a side question, what is the functional difference between spoilers
and airbrakes?

Spoilers reduce lift. Speed brakes create drag. ...and each might do a
little of both. Bob F.

Amine wrote:
An Air Canada DC-8 crashed in 1970 because spoilers were deployed
before landing, which "by the book" is a definite no-no (cf. Air
Canada 621 disaster). How come the first officer (with over 5500 hrs
with that type of aircraft) made such a decision to deploy spoilers
while still in the air? What else, when full flaps and idle power
aren't enough, can a pilot use to handle a too high/too fast final
approach if not deploy spoilers?

Go around.


--
Dudley Henriques

"Andy Hawkins" wrote in message
...
Hi,


Just read that section of the book for my PPL exam. I *think* that
spoilers
can be used differentially for roll control, whereas speedbrakes both pop
up
together so can't control roll.

But I'm probably wrong


Andy,

Spoilers deploy together symmetrically. What you are thinking of are
Spoilerons. Spoilerons come into play at slower speeds (typically when the
flaps are deployed beyond a certain point) to improve roll control at slower
airspeeds. Instead of the spoiler panels coming up symmetrically on both
wings to kill lift, only the panel on the wing with the "up" aileron will
deploy. Next time you are in an airliner watch the aileron/spoileron panels
work together at slower speeds. When the aileron moves up the corresponding
spoileron panel will move with it.

Mish

On Feb 7, 1:20*am, Amine wrote:
How come the first officer (with over 5500 hrs
with that type of aircraft) made such a decision to deploy spoilers
while still in the air? What else, when full flaps and idle power
aren't enough, can a pilot use to handle a too high/too fast final
approach if not deploy spoilers?

Dudley got this one right (Go Around), but it is kinda a loaded
question because you cannot use flight spoilers or airbrakes beyond
certain flap settings . So if you had landing flaps, spoilers are not
an option. In the older jets you would get a warning horn if you had
any flaps deployed. The best thing to do when you are to high is to
get into the landing configuration early because this will cut the
ground speed and give you the best decent rate over a given distance.

As a side question, what is the functional difference between spoilers
and airbrakes?

Nothing. The current Boeing manuals make a distinction between
airbrakes and ground spoilers because not all of them deploy in
flight. Some only deploy on the ground during landing rollout or RTO.
As a side note the flight spoilers augument roll control when you pass
10 degrees of aileron deflection (This makes Xwind takeoffs
interesting). Hope this helps,
FB

On Feb 7, 8:40*am, "F. Baum" wrote:
As a side question, what is the functional difference between spoilers
and airbrakes?

Nothing. The current Boeing manuals make a distinction between
airbrakes and ground spoilers because not all of them deploy in
flight.

Oops, should have said Flight spoilers and ground spoilers.

On Feb 7, 9:35*am, Bob Moore wrote:

As to the other question about slowing down, although not rated on the
DC-8, friends who are have told me that the DC-8 reverse thrust can be
selected in the air. With flaps up only 2 & 3 can be selected to reverse.
With flaps down, all 4 can.

Are you sure about that ? I didnt fly the 8 either, but some good
friends did and they said 2 & 3 in idle reverse only and I seem to
recall altitude and speed restrictions on this. Any DC8 jockys out
there ?

Frank

"Bob Moore" wrote ..
Amine wrote
As a side question, what is the functional difference between spoilers
and airbrakes?

Spoilers and Speedbrakes are the same panels on top of the wings
of Transport Category Aircraft. They deploy symmmetrically when
activated by the Speedbrake handle and asymmetrically when
activated by the aileron control (yoke).


I fly a lot as passenger in the BAe 146 (or Avro RJ) which has a different
arrangement. It has a speedbrake in the tailcone, which is often deployed on
short final. On top of the wings are spoilers, but I think they are only
used as ground spoilers to dump lift and put weight on the wheels to assist
braking (the RJ has no thrust reversers, presumably for noise reasons). I
know the plane was conceived as a STOL type for the London City Airport and
similar, but can anyone tell more about why this particular
speedbrake/spoiler configuration was chosen?

"Snowbird" wrote in message
...
the BAe 146 (or Avro RJ) which has a different arrangement. It has a
speedbrake in the tailcone, which is often deployed on short final. On top of
the wings are spoilers,

Getting back to the original side question: In my book, (I am a glider guy)
speedbrakes are any surface that deploys specifically to add drag. The
tailcone-mounted speedbrakes mentioned above are a great example. Spoilers are
a speedbrake installed on the wing that add drag and at the same time reduce
lift.

Just to confuse the issue, would it be OK to refer to flaps as speedbrakes?
I can point out some plain flaps on gliders that deploy to 90 degrees (or nearly
so) and produce some awesomely steep final approaches.

Vaughn