Red Wave Radio

Anyway, I was reminded of several questions I never bothered to
answer.  Sometimes when pilots are receiving instructions, they get
something like 'contact xxxx, 126.7, squawk 5.'  What does the
"squawk" signify?

Also, occasionally, I hear commercial airliners give their
designation as something like 'United 564 heavy.'  My observation
is that these are usually large aircraft, but I wondered what
'heavy' designates.  Is this a plane loaded past a certain percentage
of its capacity, or too big to use certain runway lengths, or what?

Best two exchanges of the day were:
1) a pilot asking permission to push back on a ramp that was cramped
   because it also being plowed at the time.  Ramp control: "OK,
   push back but don't block gate 18--he's next out."  Pilot: "Roger,
   don't block Charlie-18.  If the driver does, we'll kill him."
   Laughter from ramp control.

2) another pilot calling for a pushback for the second time, upset
   that there was no ground crew anywhere on the ramp.  The tower
   answered, "He's under your nose; there's a guy waving at you
   right now."
   "Oh... Roger."

Anybody interested in the Hopkins frequencies I have can send e-mail.
--
Bradley J. Bittorf|"I'll go round people up.  I'd rather truncate them, but
Allen-Bradley Co. | I'll round 'em up." --David J. Bauer, expressing his
(216) 646-4629    | frustration about the late start of a meeting, 26 Jan 1989

Quote:> I spent part of my weekend renewing my acquaintance with the airport
> frequencies at Cleveland Hopkins airport.  (Having a PRO-39 certainly
> beats the analog Patrolman SW-60, although I can no longer receive
> several closely-spaced frequencies concurrently like I used to ;-).

> Anyway, I was reminded of several questions I never bothered to
> answer.  Sometimes when pilots are receiving instructions, they get
> something like 'contact xxxx, 126.7, squawk 5.'  What does the
> "squawk" signify?

Quote:

> Also, occasionally, I hear commercial airliners give their
> designation as something like 'United 564 heavy.'  My observation
> is that these are usually large aircraft, but I wondered what
> 'heavy' designates.  Is this a plane loaded past a certain percentage
> of its capacity, or too big to use certain runway lengths, or what?

Quote:>Anyway, I was reminded of several questions I never bothered to
>answer.  Sometimes when pilots are receiving instructions, they get
>something like 'contact xxxx, 126.7, squawk 5.'  What does the
>"squawk" signify?

Quote:

>Also, occasionally, I hear commercial airliners give their
>designation as something like 'United 564 heavy.'  My observation
>is that these are usually large aircraft, but I wondered what
>'heavy' designates.  Is this a plane loaded past a certain percentage
>of its capacity, or too big to use certain runway lengths, or what?

Mike Raub

|>I spent part of my weekend renewing my acquaintance with the airport
|>frequencies at Cleveland Hopkins airport.  (Having a PRO-39 certainly
|>beats the analog Patrolman SW-60, although I can no longer receive
|>several closely-spaced frequencies concurrently like I used to ;-).
|>
|>Anyway, I was reminded of several questions I never bothered to
|>answer.  Sometimes when pilots are receiving instructions, they get
|>something like 'contact xxxx, 126.7, squawk 5.'  What does the
|>"squawk" signify?

The squawk code is a four digit octal number which is used to uniquely
identify an aircraft within a given airspace. The secondary radar polls
the transponder, which then replies with the squawk code (mode 'A') and
the aircraft's current altitude (mode 'C').

|>Also, occasionally, I hear commercial airliners give their
|>designation as something like 'United 564 heavy.'  My observation
|>is that these are usually large aircraft, but I wondered what
|>'heavy' designates.  Is this a plane loaded past a certain percentage
|>of its capacity, or too big to use certain runway lengths, or what?

The official designation of 'heavy' refers to aircraft capable of
takeoff weights of 300,000 pounds or more. There are a lot of reasons
for the use of the 'heavy' designation, but one of the most important
is for wake turbulance avoidance.

When an aircraft wing generates lift, it also generates a vortex at each
wingtip. In general, the heavier the aircraft, the greater the strength
of the vortex. The vortex of a 'heavy' aircraft can be strong enough to
flip a smaller aircraft several miles behind it. Knowing you are following
a 'heavy' aircraft alerts you to the possibility of severe wake turbulance,
and requires a greater following distance.

Recently the NTSB and the FAA have determined that the Boeing 757 generates
a tremendous vortex, even though it is not a 'heavy' class aircraft. This
vortex is strong enough to have caused an uncommanded roll of 30 degrees or
more in a Boeing 737 5 miles behind the 757. A recent bizjet crash has been
traced to the wake turbulance of a 757 ahead of it. A notice to all pilots
was recently mailed by the FAA warning of this, and ATC is providing greater
separation between 757s and other aircraft. If you hear ATC announce "Caution,
wake turbulance, a non-heavy Boeing 757 nn miles ahead", this is the reason.

If it is a mode C transponder (most are), then the transponder also
sends the altitude of the aircraft back to the radar.

    It is a code that the pilot is instructed to set into his transponder. It
should be 4 digits long.

 > 'heavy' designates.  Is this a plane loaded past a certain percentage

    An aircraft weighing more than 300,000 lbs.  The reason for the "heavy"
suffix is to warn the controllers (and other traffic) that there should be
extra spacing behind them.

I was amazed the first and only time I've seen the transponder in use in
flight.  I was flying with a friend in a Cessna 172 into Allentown-Bethlehem.
He called approach and estimated we were 12 miles out.  ATC came on and told
him to "squawk with ident".  He dialed up the digits on these four side by
side rotary knobs and pushed in a little button that read "ident" on it.
Before he could get his finger off the button, ATC came on and said, "okay,
cessna blah blah blah, we show you 17 miles out to the south east" and
started with the heading and alititude directions to walk us in.  That's
quick.

If you ever watch public television, I think NOVA did an episode on keeping
sanity in America's skies.  Good episode.  A little dated by now, I'm sure,
but the technology seemed current enough to get a feel for what ATC's go
through today.

Now that you know what squawk means, you have a better idea of what happened
about five to eight years ago when we shot down the Libyan passenger plane.

We had ships over there that bragged about being able to pick up a basketball
from 1,000 miles offshore... and about being able to pick what rowhouse a
missle will hit that will destroy half a city.  Well, as the airliner was
cruising north across the Mediterranean, we sent out a code that tells the
airplane's transponder to auto-identify.

It's still up in the air, but some people say that our ship picked up the
ident from Libyan jet fighters on the ground some 100 miles past the airliner.
However, our ship's computers identified the airliner as the fighter and we
creamed it.  Others say Libyans don't know how to use transponders and had the
computers set in the airliner to identify the plane as a fighter.  Too bad the
flight path was directly towards and over our ship.

Also, the made for t.v. movie about when our Pan Am airship was destroyed
over Lockerbie showed some pretty interesting scenes of London ATC where
they hand off planes to whoever controls the Atlantic.

"I'm getting multiple returns!"

--
Steven Jackson                                              New York University
Assistant to the Chair of Comp Sci       Courant Inst. of Mathematical Sciences

         "Not in my head.. so I don't have to think.." --  Nik Fiend

Let me know if I can help. Norm

|>
|>Heavy is 350,000 lbs
|>
|>Norm atcs fat fss

|>
|> Its my buisness. I work for the FAA.
|>
|>Let me know if I can help. Norm

Uhh... Norm, perhaps you should read the FARs/AIM a little more carefully.
From the "Pilot/Controller Glossary", quoted verbatim:

AIRCRAFT CLASSES -- For the purposes of wake turbulance separation
minima, ATC classifies aircraft as Heave, Large, and Small as follows:

  1. Heavy -- Aircraft capable of takeoff weights of 300,000 pounds
or more whether or not they are operating at this weight during a
particular phase of flight.

  2. Large -- Aircraft of more than 12,500 pounds, maximum certificated
takeoff weight, up to 300,000 pounds.

  3. Small -- Aircraft of 12,500 pounds or less maximum certificated
takeoff weight.

Quote:>Uhh... Norm, perhaps you should read the FARs/AIM a little more carefully.
>From the "Pilot/Controller Glossary", quoted verbatim:
>AIRCRAFT CLASSES -- For the purposes of wake turbulance separation
>minima, ATC classifies aircraft as Heave, Large, and Small as follows:

Does this mean that they have barf bags on board?
--
Dave Bushong, Wang Laboratories, Inc.

|>
|>
|>>Uhh... Norm, perhaps you should read the FARs/AIM a little more carefully.
|>>From the "Pilot/Controller Glossary", quoted verbatim:
|>
|>>AIRCRAFT CLASSES -- For the purposes of wake turbulance separation
|>>minima, ATC classifies aircraft as Heave, Large, and Small as follows:
|>                                    ^^^^^
|>
|>Does this mean that they have barf bags on board?

*snort* Oops. *grin*

Actually that's what happens to light aircraft that get too close to them.

*sigh*