Aviation Topic of the Week
By Michael Oxner,
November 30, 2003
This week's topic:
Airport Operations Part 5: Float Planes
From an ATC point of view, float plane operations around airports differ
very little from other fixed wing operations, but there are a minor details
on dealing with them that are worth mentioning when it comes to airport
operations. There aren't many references, unfortunately, other than the
ones mentioned in previous topics such as for the traffic circuit and taxiing.
While none are directed at float planes specifically, they do still apply.
Read on to see what I mean.
Wheeled Operations
Clearances
Oddities
Planes Without Wheels at Airports
Clearances
Float Plane Operations off Airport
Departures
Arrivals
Wheeled Operations and Clearances
For the most part, float planes operate around airports like fixed
wing aircraft. That is, most have wheels and are able to taxi, take-off
and land just like any other aircraft. As such, they are to be treated by
both pilots and controllers in the same ways. Clearances for taxi, take-off
and landing are all to be said by controllers, and interpreted by pilots,
in exactly the same way. Not much more to be said in this case. There are
a few items to be cautious of for controllers, though.
The first thing about taxiing amphibious float
planes around an airport is dealing with the various types. If you're
looking at a Canadair CL-415, a Lake 270 Renegade, a Grumman Goose, or
something similar, the aircraft's fuselage is the waterborne hull. The
landing gear protrudes either from the body or the wings and therefore
is basically just like any other aircraft. If the aircraft in question
is like a Cessna 185 or other standard land-based airframe adapted for
use on water by adding floats, the story is a touch different. Not so
much in the handling of regulations, but in the handling of the aircraft.
Most aircraft adapted to floats will sit considerably higher up than it's
wheeled counterpart. This results in the aircraft having a higher center
of gravity. The higher the center of gravity, the harder it is to turn
the aircraft without inducing too much roll while it operates on the ground.
This is not to say that pilots of float aircraft have a tough time of taxiing
float equipped aircraft, but rather that these pilots may not be able to
hustle out to position and commence an immediate take-off roll as quickly
as an aircraft with a wide and low wheel base. It's more something to
consider when assessing if a pilot can do an immediate take-off, or vacate
a runway expeditiously after landing. As an airport controller, you may
want to allow a little extra time (not necessarily a lot) for the handling
of such aircraft. Also, consider the effects of propwash, jetblast, or rotorwash
from other aircraft operating nearby.
Planes Without Wheels at Airports
This sounds kind of strange, but there are many examples of float planes
that do not have retractable wheels using land aerodromes. The landings
will involve a gentle touchdown on the grassy areas between runways and
taxiways. The grass generally provides enough of a cushion, and when it's
moist allows less friction and a more gradual, natural braking action. The
aircraft will then be placed on a wheeled "truck" for movement to a hangar
or maintenance facility. This truck is more or less a cart that the floats
sit on.
The take-off will normally be accomplished with the same truck that
allows the ground movements. The aircraft will have any attachment points
removed and basically just sit with its weight on the cart and taxi out.
The take-off is completed in the same manor as a land aeroplane, except
the float plane leaves its wheels behind. A ground crew must then proceed
onto the runway and remove the cart.
When aircraft are planning to use an airport
in the above fashions, the rules are much as they have already been stated
in previous topics. For example, the take-off clearances would be issued
just they would to an aircraft on wheels. The one concern would be to provide
extra time to allow the ground crews to remove the cart for subsequent aircraft.
The runway must be cleared of such known "FOD" before others use it. For
this reason, this sort of operation must be approved in advance by ATC.
A phone call to the tower should provide the information necessary, and
an opportunity to coordinate a time for the operation to take place. As the
cart ties up the runway, ATC may deny immediate approval, and may specify
a better time with respect to other traffic. As for the landings on the grass,
this is just the same as for helicopters as mentioned last week. The grassy
areas surrounding runways are not part of the manoeuvring area, and so landing
clearances are not normally issued in conjunction with such operations.
Float Plane Operations off Airport
Lastly for this topic, we'll talk about operations off the airport.
There are two kinds of operations of this nature that ATC may be concerned
with, but they're both basically treated the same. Some airports have large
ponds near, or even on, the airport grounds. Many, many airports have lakes,
rivers or harbours nearby the field that are off airport property but
within the control zone. In both cases, the aircrafts need approval of
the control tower to be in the air. Also, in both cases, there is a complete
lack of any authority over the surface which the aircraft is parked on,
or intends to land on.
For departures, the pilot should obtain
some sort of approval from the tower before liftoff. In many cases, the
pilot will be able to talk to ATC on the radio prior to take-off. In other
cases, due to terrain or other circumstances, the pilot may have to contact
the tower by phone before getting into the aircraft (or by cellular phone,
of course) since the radio calls may not reach the tower. The tower controller
should at this point issue winds at the airport, stating this fact along
with the wind information, issue altimeter setting, inform the pilot of
any known traffic, issue any restrictions required (as few as possible)
and remind the pilot that the departure is at "pilot's discretion". If a
phone call is the source of first contact with the tower, it would be a really
good idea from an ATC point of view to ascertain when the operation is likely
to take place, too, so you can plan other traffic around it if they can't
talk directly to the pilot until he is airborne. Example? "Merlin 22, winds
at the airport are 220@10. Traffic is a Cessna 172 doing left hand circuits
to runway 24. Departure from Miller Lake is at your discretion. Report airborne."
The same is basically true for arrivals,
except that the aircraft is normally already in contact with the tower.
Once again, no landing clearance is issued, although airport winds and
other information may be given. It isn't always necessary to get an arrival
message, although ATC may request the pilot to report having landed. This
is often not as important as the departure call prior to take-off, since
it is likely any traffic conflicts are resolved before the aircraft lands.
In the case of alerting services being required, such as for flight plan
closure, the pilot should already realize that an arrival message must
be filed with someone. This may include a closure of the flight plan in
the air, and then an actual on time, or arrival report, may not actually
be needed. Once again, the surface may be in the control zone, but since
it is not part of the manoeuvring area of the airport, no landing clearance
is issued by ATC, though other information may. "Romeo Alpha Tango, winds
at the field are 310@5, touchdown in the harbour at your discretion."
This has to be one of the shortest topics I've ever written. I'm sure
I didn't answer all the questions requested here, but this part fell in
nicely with the Airport Operations series, so I thought I'd at least answer
these parts. Anything to say about what's written here? I'm willing to take
negative comments and complaints just as I am willing to take positive remarks.
My e-mail address is moxner@nbnet.nb.ca.
Thanks again for reading!