Aviation Sri Lanka
the roles that ground facilities play during an emergency is important, but it's
equally critical to be well versed in our pilot responsibilities when things are
tight and help is needed. Radio failure is a great place to start, followed by
an examination of other in-flight emergencies.
potential radio failure is very hard to predict, although a thorough preflight
check could give some clues. A loose or broken antenna is an obvious signal, as
is a popped circuit breaker, or a loose, worn, or frayed alternator belt, if you
can see or test the belt. Another clue is a radio that tends to slip in and out
of its rack. Another is garbled reception on the ground or controller comments
that your transmission is weak or scratchy.
any of these symptoms exist on the ground, the radio's either sick right now or
it could die on you at an inappropriate time. The only solution is to get it
fixed or the potential cause corrected before venturing forth.
assume, though, that everything checks out on the ground, so off you go. After a
while, you become conscious of the fact that there hasn't been much chatter over
the air for several minutes, which causes you to wonder if …
When a problem is suspected:
the squelch or turn up the volume. If you hear the typical static, the set's
probably OK; there's just been a period of unusual radio silence.
Wiggle and push all mike and headset plugs to verify that they are firmly in
the circuit breakers. If one has popped, let it cool for a couple of minutes and
then reset it. You might get your radio back, but a popped breaker is
symptomatic of a problem, so have a mechanic investigate the cause when you're
back on the ground. If the breaker pops out again, leave it alone; never force a
breaker to remain reset.
the ammeter. If it shows no charge, test it by turning on the landing light. If
the needle doesn't move, you can be sure the alternator has died or its belt has
broken, in which case, the only electrical power will come from the battery. The
engine won't quit, because the ignition system is independent of the alternator
battery system, but without an alternator, the life of the battery is only about
two hours. After that, you'll have no electrical power at all. Consequently,
turn off all nonessential electrical equipment, except one radio, and head for
home or the nearest airport. Enough battery power might be left to make whatever
radio contacts are necessary before landing. ( most of the procedures explained
above are not relevant to modern day aircrafts as they are equipped with
alternative backup systems.)
failure is real and it's no longer a matter of suspicion: the radio is dead or
rapidly dying. Now, what are your options? Five of the most likely answers
depend largely on the situation.
You are going into a Class B or Class C primary airport. To make it simple,
let's say that you had enough battery juice left to monitor the ATIS and to be
cleared into the TCA or to establish contact with the ARSA approach control.
Once inside the TCA or ARSA, though, the radio dies completely and you have lost
all transmitting and receiving contact with approach.
this point, squawk the 77001/7600 code and continue through the TCA/ARSA to the
airport. Approach knows your intentions and, seeing the RF code on the
radarscope will protect you as well as advise the tower of your predicament.
within the ATA, watch the tower for light signals, as summarized in FIG. 10-1,
that will clear you to land or tell you to keep circling. Once on the ground,
pull off on a taxiway, and continue to watch the tower for the green light that
authorizes you to taxi to the ramp.
same scenario applies if you are transiting a Class B or Class C airspace or if
you're already in one of the airspaces but intend to land at a satellite
airport. The main point is to keep right on going in accordance with your
announced intentions. Don't wander around in those high-density areas. If you
deviate from what you have told the controller, the controller does not know
what to expect, which could cause confusion in the efforts to maintain an
orderly flow of traffic.
You want to land at a Class D airport that has no approach control and is miles
from a TCA or an ARSA. Some distance out, the radio dies, so you squawk the RF
transponder code. The nearest center or approach, seeing the code on its radar,
will track your flight route and, if it appears that you are headed for the
controlled airport, will notify the tower of your probable landing intentions.
you near the field, keep a sharp eye out for the light gun signal, especially a
red signal that tells you, in essence, not to land. If you see no signal, cross
over the field about 500 feet above traffic pattern altitude, note the flow of
traffic, fly upwind over the active runway, and watch for the green
"cleared to land" signal. Keep an eye on the tower, though, even after
the clearance signal. For a variety of possible reasons, you might get a red
light on the final approach. Do a go-around then for another approach, as long
as you get the green light again.
You have not been using center or been in contact with approach, but you want to
land at the primary airport in a TCA or an ARSA, and the radio has failed. Your
alternative? Only one: Land outside the area and request entry approval from
approach by telephone. You probably will not get it, though, unless the traffic
is very light and you are close to the TCA or ARSA. Even then, the odds are
against any approval without an operating two-way radio.
You are on the ground at an uncontrolled field, The radio is dead, but you want
to fly to a nearby Class D airport to have it repaired. Your only option is to
telephone the airport tower, explain the situation, and ask for approval to
enter the ATA.
on the probable traffic at your estimated arrival time, approval might or might
not be forthcoming. You are on the ground and there is no emergency, so airport
conditions will largely determine what the Class D tower says. In most cases,
though, tower supervisors want to help, and, traffic permitting, will attempt to
accommodate your request.
Prepare with alternatives
VFR radio failure, when viewed objectively, is really more of a nuisance than a
true emergency and should not be the cause of cockpit panic, The best advice,
unless you're actually in a Class B, C, or D airspace when the failure occurs,
is to land at the most convenient uncontrolled airport.
the other hand, if the set dies while you're in one of those controlled
airspaces, stay with your already-announced intentions and proceed directly to
the field. With the RF code on the radar screen, the controller will protect you
from other aircraft until you are in the ATA. From that point on, the tower
controller will clear you for landing with the help of the light gun.
This procedure was introduced a long time ago and still in practice to accommodate any failure in existing radio communication system in the control tower. The signaling to the aircraft or the vehicles moving on the air field is done by 3 color lamp called "Light Gun". Following table explains the specific information provided by color pattern.
apparently, you and I have to know what those on the ground expect of us when we
are faced with a radio failure, otherwise, we could be guilty of causing a lot
of confusion and perhaps hazardous conditions for others and ourselves. The only
answer is to be prepared for the problem and have a clear set of alternative
actions in mind if the problem should ever become a reality.
aid in attracting attention to an aircraft in distress and its need for help, is
"chaff." This consists of a small packet of strips of coated material,
usually aluminum foil, If unable to communicate, a pilot should fly a straight
course, dropping a box of chaff every two miles until four packets have been
dropped. Then, continuing on the same straight course for two miles, he should
make a 360- turn to the left; another two miles and another 360' turn to the
left, and so on until four 3600 circles have been flown. This total pattern
(four drops of chaff and four 360' turns at 2-mile intervals) increases the
probability of detection by the radar controller-and of the assistance needed.
same constant direction of flight should be maintained after the total pattern
is completed, so that ground personnel may have continuing information as to the
position of the aircraft in order to provide help. Since the dropping of chaff
temporarily prevents the functioning of radar for its normal uses, it should
never be used except in case of genuine distress or upon direction by the ground
FAA makes it very clear that when an emergency develops while in flight, only
one person has the final responsibility for the operation of the aircraft. That
person is the pilot. The FAA further makes it clear that rules and regulations
are pretty much tossed aside when action is required to meet the emergency. In
the process, however, the FAA stresses that the pilot should request immediate
help through radio contact with a tower, a center, or a flight service station.
are classified as distress or urgency. A distress condition is one of fire,
engine failure, or structural failure. In other words, the situation is dire,
immediate, and life-threatening. Urgency is not necessarily immediately perilous
but could be potentially catastrophic, as being lost, a low fuel supply, a
seriously malfunctioning engine, pilot illness, weather, or any other condition
that could affect flight safety. When any of these conditions arise, the pilot
should ask for help now, and not wait until the urgency becomes a distress.
AIM outlines the appropriate emergency procedures in some detail, the following
summarizes the essential elements for the VFR land pilot.
I've touched on before, but when either an urgency or a distress situation
develops, immediately enter the 7700 emergency squawk in the transponder. That
code then appears on the screens of all radar-equipped facilities within radar
range and, by sound as well as the flashing blip, attracts the controllers'
attention. As controllers put it, "lights light and bells ring."
Ground help is, of course, hard to offer if the pilot has not been in contact
with a center or any other facility, but at least they know that there's an
aircraft in trouble out there and they know its location.
you dial in 7700 or call a ground facility first is a moot point in a distress
condition. Unless you were already tuned, let's say, to a center, it might be
better to squawk the code immediately and then change the radio to center,
approach, a tower, or an AFSS. If you don't have time to search for one of those
frequencies, always remember 121.5. This is the emergency-only frequency that is
guarded by direction finding stations, civil aircraft, centers, military towers,
most civil towers, and FSSs.
faced with a distress condition, start the radio call with "Mayday"
repeated three times. This is the universal call for assistance and comes from
the French, "M'aidez," pronounced "Mayday," meaning
"Help me." Distress messages have priority over all others, and the
word "Mayday" commands radio silence on the frequency in use.
an urgency condition, begin the call with "Pan-pan" repeated three
times. Urgency messages have priority over all others except distress and warn
others not to interfere with the transmissions.
the problem of time limitations in an emergency situation, the FAA suggests that
as much of the following as possible be communicated, preferably in this
1."Mayday, Mayday, Mayday" or
"Pan-pan, Pan-pan, Pan-pan"
2.Name of facility addressed
3.Aircraft type and identification
4.The nature and of the distress and type
6.Pilot’s intention request
7.Present position and heading, or it' lost, last
known position, (line, and heading since that position
8.Altitude or flight level
9.Hours and minutes of fuel remaining
10.Any other useful information, as visible
landmarks, aircraft color, emergency equipment on board, number of people on
the emergency locator transmitter (ELT) if possible
Pilot responsibilities after radio contact
in contact with a ground facility, a pilot has certain responsibilities:
Confess the predicament to any ground station;
Communicate as much of the distress/urgency message as possible;
Comply with instructions and advice;
Climb, if possible, for better radar detection and radio contact.
LOCATOR TRANSMITTER (ELT)
locator transmitters, designed to assist in locating downed aircraft, are
required by FAR 91 for most general aviation aircraft, although certain
exceptions are allowed. An ELT is a battery-operated transmitter that, when
subjected to crash-generated forces, transmits a distinctive and continuous
audio signal on 121.5 and 243.0. The life of a transmitter is supposed to be 48
hours over a wide range of temperatures.
on its location in the aircraft, some ELTs can be activated by the pilot while
airborne. In other installations, the ELT is secured elsewhere in the fuselage
and cannot be accessed in flight. These are activated only upon impact or by the
pilot when on the ground and out of the airplane.
of their importance in search and rescue (SAR) operations, ELT batteries are
legal for 50 percent of their manufacturer-established shelf life, after which
they must be replaced. Periodic ground checks of an ELT should be made, but only
in accordance with the procedures outlined in AIM.
this discussion of emergencies is necessarily limited in scope as well as depth,
one pilot responsibility hopefully stands out: the responsibility to be prepared
mentally and physically for the unexpected, the nonroutine. If you fly long
enough, sooner or later you're going to encounter an emergency situation of some
nature. Perhaps it will be very minor and easily correctable; perhaps it will
require every bit of knowledge and expertise you have amassed. Whatever the
case, the odds of something going sour sometime are close to 100 percent.
that's a reasonable bet, preparation (and all that preparation implies), is
absolutely essential. Beginning with every pilot's very first flight, they ought
to be asking two questions: "What could go wrong? If 'what could go wrong'
did go wrong, what would I do?" As suggested elsewhere in the book, this is
the process of potential problem analysis (PPA).
fire in flight; the engine bucks and coughs for no apparent reason; the engine
quits entirely; a bird strike smashes the windscreen; a passenger has an
apparent heart attack; you're lost; the fuel gauges are showing close to empty;
electrical power is interrupted: What would you do? It's a matter of
anticipating these as well as other potential problems and then having
alternative plans of action firmly in mind in case a potential ever became a
reality. (As always, above all else, fly the aircraft first, then follow through
with your planned and alternative actions.)
While transponder and radio procedures are perhaps only small elements in handling a distress or urgency situation, they could be major factors in helping you get that airplane down safely and in one piece. Our entire ATC system is designed to maximize safety, and the folks on the ground have had drilled into them what to do when a pilot calls Mayday or Pan-pan or squawks the emergency or RF code. But controllers can only help pilots to the extent that pilots can help controllers. That's where personal preparation and the skill with which pilots handle the emergency, comes into play.