I have a question on aircraft takeoff speed. I understand that once an aircraft has reached v1 speed,
it is no longer possible to abort the takeoff. Why is it so ?. If we assume that a runway is longer than
necessary then will this restriction of v1 still apply for takeoff abort ?
Another question - what are the different exterior lights on a commercial aircraft and what is the
purpose of each of them ?
Thank you
Sridhar
Hi Sridhar,
Here are the answers to your two questions:
1. The V1 Takeoff Decision speed is the speed used as
a reference in
deciding whether a takeoff is to be continued or aborted when an engine
failure occurs. Your question as to why it is not possible
to abort the
takeoff when the aircraft has reached a V1 speed is basically one based
on
safety reason. From past statistics, abort after V1 have resulted in
disaster in many cases. Why? Because, such aborts would result in brake
fires due to the higher speeds. So
unless absolutely necessary, any emergencies after V1, the takeoff MUST be
continued. It is safer to take off with the emergency, handle the
problem in the air, dumped the excess fuel and then carry out a controlled safe
single-engine landing at a lower speed. Please read a similar topic in
an earlier FAQ.
Regardless of whether you have a longer runway, V1 still applies.
It may
sound not logical to you. It means that you may end up in a fire
at the end
of the runway instead of outside the runway! It doesn't mean that it is
impossible to abort after V1. You can still do so but is recommended
that you should not abort after V1 to avoid a fire with consequential and fatal
results.
2. There are two important exterior lights in any airplane.
At the tip of
the right wing is a green light and on the left wing is a red light.
They
have important functions at night when one find it difficult to know if
the
aircraft in on a collision course or flying in the same direction.
If you
see the red light on the right at night, then you can tell that the
aircraft
is heading towards you. If the green light in on the right, it is
safe
because the airplane is flying together with you on the same direction.
Also, if both aircraft are converging, the aircraft on the right has the
right of way because he sees the Green light on the right wing of the
other
aircraft and the aircraft on the left sees a Red light on the wing of
the
right aircraft!
Regards,
Capt Kay.
* Is it possible that a pilot could loose control during turbulence especially when it goes through an
air pocket and drops. I felt that it would just continue dropping and the pilot might not be able to
regain control.
* Also, I have not had too much problem while flying long routes on
bigger aircrafts like Boeing 747, but during internal flights on
smaller
aircrafts like the Boeing 737, I feel that it hits far more air pockets.
Is it true that larger aircraft is more stable during air pockets
than smaller
aircrafts like the 737?
* Is there reason to be scared during such times...I always ensure
that my seatbelt is fastened at all times during flight
I look forward to your answers.
Thanks again so much.
Regards
Varghese Paul
Regards
Capt Kay
8.
Fear of flying due to terrorism?
Hi Capt Kay,
I would like to thank you for your website. I love to fly but am
scared of
it, but all the information I have read so far makes me feel pretty good. I
have a
question about flying. With the threat of terrorism and the fact
that I am flying to London from Chicago next month, is it safe to
fly with all the security in place?
I am worried about the terrorist aspect, and if with
these new security measures, can I fly with no worries about terrorism
in the air?
Thanks
Steve
Hi Steve,
Thank you for visiting my Site. Your question is quite difficult to
answer
at the moment because the full security measures as envisaged by the
Aviation Authorities worldwide are not fully implemented yet due to many
constraints.
I can say that security checks are getting more stringent everywhere
in the
major Air Terminals but you cannot totally eradicate the risk of terrorism.
Treat the air safety aspect as you would treat travel by other modes of
transport, like coach or the underground train.
Technically, it is safe to fly anywhere if the security checks are
full-proof but can anyone guarantee that? Anyway, I wouldn't
worry about
that because the chances of terrorist attacks are fairly slim. I
think the
chances of any threats would be just as great if you take an
underground
train to anywhere from the London Marble Arch Station.
Hope that will make you feel better.
Regards,
Capt Kay.
9.
Optimum cruising speed of the Boeing 777
Dear Capt Kay,
I am kind of a puzzled by this. I was at Singapore Changi Airport
yesterday night. Singapore Airlines, SQ 36 (B777) was operating a flight from
Singapore to Amsterdam. In its Air Traffic clearance, controllers assigned SQ 36 to cruise at FL280
at Mach 0.84 speed. However, the pilot said that he could only go at
Mach 0.80.
Why can't he go at Mach.84 while 15 minutes ago an Air France
B777 can accept Mach0.84 at FL280 as assigned. The reason controllers
try to assign the highest speed possible because of the huge amount of
flights departing around the same hour mainly using the same route to Europe.
In the end, the ATC controller had to delay
all of the rest of the European B744 flights because their minimum
cruising speed was at .84 or higher. SQ 26 was the worst
affected, departed Singapore 2 hrs 15mins late.
Normally, these European flights uses the same
Airways, so they got
to go in the sequence with 10 minutes in separation. If you have to depart 10 minutes behind a flight which
has gate real far from the runway, you can only start your push back
once that flight has reached the holding point, which is obviously
more than 10 minutes of wait.
If you see flights from Singapore to Europe
arriving late, here is the reason why.
Any idea why SQ 36 had to go at .80? It has definitely slowed every
other flights.
Thanks and God Bless you. Hope to hear from you soon.
alvin
Hi Alvin,
You seems fairly knowledgeable about
the Air Traffic Procedures, traffic spacing and appears to know
what is going on in the various flights departing from Changi
Airport.
Anyway, your question as to why SQ 36 had
to go at Mach .80 is simple. That is the optimum speed
calculated by the aircraft computers to cruise economically at
FL280. Of course he could follow the Air France Boeing 777 and fly at
Mach .84 but he may run out of fuel unless he carries extra.
Carrying too much extra fuel may be uneconomical.
A Boeing 777 normal
cruising speed is Mach .84 at FL 350 - FL 390 and not at FL 280.
At FL 280, the best and most economical cruising speed is around Mach
0.80.
I hope I have answered your question.
Regards,
Capt Kay
10. Flying a simulator and
the real thing
Hi there,
Wonderful site, although I'm sure you've heard that about a million
times by now.
Personally, I love flying. I'll just repeat that...I love
flying! I've got far too many passenger anecdotes, but I'll stop
after saying that my favorite flight was in 1st class on an L-1011
(with backward facing seats and a table, no less! :) ).
Unfortunately, I've never had the resources or
opportunity to be able to take up the business in reality. So, I
use simulators. I probably fly daily on Microsoft's FS2002, and
as it's as close as I'll get. I kinda want to strive for as much
realism as is possible sitting behind a monitor in your study.
If it's okay with yourself, I have a few basic questions that would
greatly help me in enjoying my simulations more. I hope you are
able to answer them, and it'd be wonderful to know there was a real
pilot out there helping me!
1. According to the simulator, FAA regulations in the US limit
airspeed to under 250kts under 10000ft. Is this a global
restriction, or just present in the USA?
2. Do you guys for real navigate using GPS all the time? When
actually flying, how often do you rely on VOR or NDBs? I'm guessing
it's probably a very rare thing these days, but hey...sometimes it
feels like cheating to just load the computer with a GPS IFR route and
let ATC talk me through the whole thing. Kinda feels like I
should be doing more, y'know?
3. In terms of autopilot....when flying in the simulator, I tend
to pretty much throw the autopilot on very shortly after takeoff,
having preloaded it with my cruising altitude and an ascent rate of
about 1400 or 1500. Once ATC start giving me the new headings,
I'll just punch those into the autopilot and pretty much let the plane
do it's thing. Does that follow what really happens, or are you
guys in control during initial climbing?
That's about all I can think of just now. I'd just like to feel that
I'm getting a little closer to reality when I'm 'playing' at it.
I hope to hear from you soon,
Take care, and clear skies to you....
Dave McKinney
Hi Dave,
I can see that you do have a great enthusiasm
about flying. Simulators are great procedural trainers but
nothing can actually compared with real life flying. To tell you
frankly, my son, a non pilot flies better than me in the simulator in
the computer!
Here are the answers to your
questions:
1. A speed
restriction of 250 knots below 10,000 feet is practiced
in many parts of the world, especially when the traffic is heavy but
if the airspace is light with very few aircraft, the restriction is
not imposed. The main reason is that it is easier to space
aircraft when they are flying slower, and hence safer for all
concerned.
2. The GPS
or global positioning system, is installed in all later aircraft
models, the Boeing 777 being one of them. There are still many
aircraft flying around without the GPS installed yet. The GPS is
so far the most accurate navigation system and usually two systems are
on at all times unless they become unserviceable.
The NDBs (non directional
beacons) are almost Jurassic now but still used in many third word
countries. They are not very accurate and subjected to many
errors. The VORs (very-high-frequency omni-directional radials) are
still being used for radial tracking and cross-checking when the
aircraft are using the GPS for navigation.
3. On the Boeing
777, the autopilot can be selected on above 200 feet above ground
level after take off. Most of the time, the pilot will make use
of the autopilot on the climb because it eases the workload of the
crew especially during an emergency. Sometimes, a pilot may elect to fly
manually during the climb just to get his hands on the control column
or to maintain his proficiency
because in a flight test, one of the exercise calls for flying without
the aid of autopilot. Otherwise, the autopilot is engaged
throughout most of the flight. It is smoother, more
economical and safer with the autopilot on. In fact, in really bad
weather with very limited visibility, the autopilot even lands the
aircraft by itself. The pilot only resumes control of the
aircraft after it has safely landed on the Runway.
The challenge is actually
flying the aircraft manually but it is the autopilot, being such an
accurate system, that often takes the fun out of flying!
Happy flying to you always!
Capt Kay
11.
What causes the air pressure inside my ears when the aircraft takes
off?
Hello Capt Kay,
I have just been to your "Fear of flying"
website and I think it is
very informative especially if you are interested in jet aircraft as I
am.
I would like to thank you for making a site such as this and
congratulate
you for doing such a good job of it.
I wonder if you could/would possibly answer a question for me. I do
not
actually have a fear of flying (although I did a little on my first
flight) but I do seem to suffer from a feeling of air pressure in my
head when the plane takes off and when it turns and of course if there
is turbulence. This does not seem to happen during descent unless the
plane turns on approach. I also suffer from this in elevators whether
they are going up or down. Can you tell me what might cause this and
how I could fix it?
A. John
Hi John,
Thank you for visiting my Website.
What you are experiencing is quite normal to any one with a slight
cold. I
usually advice anyone with a severe cold to refrain from traveling by
air
for they may risk bursting their eardrums.
The feeling of pressure in your head is in fact due to the exertion of
your ear drums caused by the unequal pressure between your middle ear
and the air outside the body. Remember, when you swallow, you hear a
slight popping sound in your ears. It means you are normal. Air
in the middle ear is always being equalized on both sides of the
eardrum through a small pencil lead size hole known as the Eustachian
tube, which is a membrane-lined tube, connected to the back of the
nose.
If you have a cold, the
membrane will become sticky and wet. It causes the middle ear to be
blocked. When the tube is obstructed, the middle ear cannot
equalize. When an aircraft climbs or descents, the outside air pressure
changes and the vacuum inside will tend to stretch the eardrum outward
or inward. If
the pressure is not equalized in time, it may stretch the eardrum
membrane. This will prevent the eardrum from vibrating normally
and any sound may appear abnormal and cause pain in the ear too.
To overcome the problem, try swallowing, yawning or move your jaw from
side to side. This will exercise the muscles and hopefully, open the
Eustachian tube if it is not very sticky. Many years back, Airlines used to provide
sweets to passengers before take off. Today, all jet aircraft are
pressurized and hence the pressure changes are very much reduced.
The giving sweets are no longer practiced by most Airlines lately, in which case you may have to buy your own sweets the
next time you fly!
If you still find you still cannot get rid of the blocked ears despite
the
recommendation above, try this. Pinch your nostrils shut, close
your mouth and
blow your nose very hard a few times until you hear a popping sound. If it
pops, then you have succeeded!
The explanation above is similar to going up or down an elevator.
You
mentioned that it also happened when the aircraft was turning and during
turbulence. What actually transpired was that, the aircraft was climbing
all the time and the pressure outside the body was reducing, perhaps at a
slower rate than if you were flying a non-pressurized aircraft.
My advice is, do not fly if you have a cold. If you are not sure
how bad your cold is, try the pinching nose test, described above on the ground
first.
If your ears pop, then your Eustachian tube may be able to be cleared
if you
do the similar test in the air. To play it safe, consult your
doctor first before you fly if you have a cold!
Hope I have answered your question.
Happy flying on your next trip in the air!
Regards,
Capt Kay
12. Boeing 777
Cruising Speeds
Hello Capt Kay!
Very informative, extensive and thoroughly enjoyable
site!
I have 3 issues lingering in my mind.
1. When aircraft are assigned altitudes during peak periods, are
they also assigned cruise speeds? Or, are these factors already taken
into account
for the various aircraft types by the controllers when the flight
plans are being filed?
2. During the cruise, is the Mach Number preset by the
auto-throttle or is it gradually achieved by manually setting the
throttle levers?
3. And finally; what are the cruising speeds of the various
airliners?
Thank you very much in advance and take care of yourself and the
passengers.
Rani Isaksen
Faroe Islands
Hi Rani,
Thank you for visiting my site. Here are the answers to your
questions:-
1. Every aircraft has an optimum cruising speed at a particular
level. For
the Boeing 777, it is Mach 0.84 at around 35,000 feet or Mach 0.86 for
the
Boeing 747-400. When filing a Flight Plan, the cruising speed
must be given for every types of aircraft. During peak periods,
the ATC or Air Traffic Control may assign a common speed for spacing
to ensure safety. So a Boeing 747 pilot may not be able to fly
his desired speed of Mach 0.86 and fly at Mach 0.84 instead if she is
behind a Boeing 777.
2. On the Boeing 777, the cruising speed at any level is
calculated by the
computer of the aircraft. For example, at 28,000 feet, the
computer (FMC)
will command a speed of Mach 0.81. When the computer is coupled
or
connected to the auto-pilot and the auto-throttle, the power setting
is
achieved automatically. There is no need for the pilot to
manually set the
throttle settings as he would have done in older aircraft.
3. Here are the optimum cruising speeds for some of the
more modern
Airliners flying today.
Airliners
Optimum cruising Speeds (Mach)
Boeing 747-400
0.86
Boeing 777
0.84
Boeing 767
0.80
Boeing 757
0.80
Boeing 737 -800
0.78
Boeing 737 - 300/400/500
0.74
Airbus 340 -300/600
0.82
Airbus 330
0.82
Airbus 320
0.82
Airbus 310
0.78
McDonnell MD-11
0.85
For your information, Mach 1.0 is equivalent to the speed of sound.
It is 758 miles per hour or 660 knots at sea level. This speed varies
with altitude and temperature. Mach 0.84 means the speed of the
Boeing 777 is cruising at 84 % the speed of sound at 35,000 feet.
Bye bye and safe flying!
Regards,
Capt Kay.
13. Boeing 777
Thrust Asymmetry Compensator
Hi Capt Kay,
I have a question with reference to the Boeing 777.
I want to know about the mode of operation of the Thrust
Asymmetry
Compensation (TAC) which is a special feature of the Boeing 777.
As I understand, it is a system which helps the pilot to handle an
engine failure during the critical stage of the flight, for example,
an engine out after a V1 Speed on the Runway. Here are my questions:-
1. Is the LNAV button always engaged? As far as I know,
there would definitely be a Flight Plan which would take care of this
condition to safely guide the aircraft for a go-around and land at the
same airport.
2. TAC will automatically control the rudder. So
when an engine goes out, the
auto pilot adjusts the rudder to compensate. In this scenario, if the
pilot initiates a turn, the rudder needs to be applied. Will this have
any consequences?
Also, if the plane is flying in the LNAV Mode and
aircrafts makes a turn,
then the FMS would be giving the appropriate commands to maneuver the
aircraft.
As TAC is a separate system from the FMS, would they not be receiving
conflicting data? Which system has the priority?
3. FMS handles engine out conditions. So why one more
system called
TAC. They are not found in any Airbus aircraft or in the
B747-400. What makes the difference?
Please explain in detail how and in what different ways this situation
is handled. How the systems interact?
Thank you
Warm regards
Srihari J
Software Engineer
Honeywell
Hi Srihari,
I believe you have some knowledge on the LNAV and the operation of the
FMS. The TAC is unique in that is is only available on the Boeing
777. The TAC or Thrust Asymmetric Compensation system helps the
pilot control the yawing effect of the Boeing 777 when it suffers an
engine failure. When the system senses the thrust level on one
engine differs by 10 % or more from the other engine, it automatically
adds rudder pressure to minimize the yaw. After a few seconds,
the TAC applies sufficient rudder to make it possible for the pilot or
auto pilot to center the control column. The TAC can be manually
overridden by making manual rudder input.
Now to answer your 3 questions:-
1. The LNAV is always engaged before the take off.
If the auto pilot is
engaged after 200 feet above ground level, any yawing caused by an
engine
failure would be taken care of by the auto pilot and the TAC.
The
engine-out profile and route can also be programmed on the FMS to
enable the aircraft to land safely on the departure airport or at the
alternate airport.
2. If a pilot initiates a turn with the TAC whilst
controlling an engine
failure, any rudder input will have no major consequence because, as I
have
explained above, the TAC can also be manually overridden by manual
input.
3. You must be clear of the function of the FMS, the
Flight Management
System and the TAC. The FMS can handle the engine-out
performance. What it means is that it can provide VNAV and LNAV
data to the pilot and auto pilot but it could not control the yawing
of the aircraft caused by an engine failure. Only the TAC can control
the yawing moment of an engine failure.
So this is a special system peculiar on the Boeing 777 and not on any
of the
Airbus aircraft or Boeing 747-400.
Safe flying,
Regards,
Capt Kay
14. Severe
turbulence and pilot's command of English Language
Dear Capt Kay,
I often fly with ANA-All
Nippon Airways in Japan. I am quite happy flying with this company.
The only thing that worries me is that sometimes the cabin crew warn
the passengers that " we expect some severe
turbulence....". I thought that pilots can and should
avoid severe turbulence at any time. Is it not true ?
Another matter that worries me
concern the pilot's knowledge of the English Language. It is usually very
poor. I wrote a letter on this subject to ANA and their reply
was that, even if the pilot could not speak good English they were
very well acquainted with the technical language used to communicate
with the control tower. Does it make sense ? And what would
happen in case of an emergency ?
Best regards and thanks for
your site which is very helpful to frightful passengers.
F. De Marco
Hi Marco,
Thank you for
visiting my Site. Below are the answers to your questions:-
Pilots do
not like turbulence too. They will endeavor to avoid
turbulence whenever possible. Areas of turbulence can be
quite widespread and it is impossible to avoid them sometimes.
In this case he has to ride through them but gives warning to the
passengers via the cabin crew, to fasten their seat belts.
Rest
assured that, in such circumstances, he would make all efforts
to get out of the turbulent condition as soon as possible, either
climbing to a higher level or turn away from the turbulence.
His actions to avoid these areas are subjected to the approval of
the Air Traffic controllers. Bear in mind that there are other
aircraft which may also be experiencing the same turbulence
too. As I have explained in other FAQs on this
topic, the aircraft can withstand all these minor and
uncomfortable turbulences.
It is true
that some foreign pilots are not very conversant in the English
Language because it is not their mother tongue. This has prompted
some Insurance Companies to impose some restrictions,
whereby a certain percentage of these Airline pilots must consist of
fluent English speaking expatriates before they can be covered
if they wish to operate into the USA.
When a
pilot is qualified and certified, he is competent to
operate the aircraft regardless of his Nationality. In an
emergency, he is trained to use the standard technical
term or phraseology even though he may not be very good in the
English Language. For example, in an emergency, all the pilot need
to say is Mayday! Mayday! Mayday! and provides the standard
information which he has been trained to transmit. He would
be accorded all the assistance immediately.
Hope my
answers would ease your mind a little.
Enjoy a
safe flight always!
Regards,
Capt
Kay.
15. Dreaming
of becoming an Airline Pilot.
Hello Capt Kay,
I was wondering if you would be able to give me some advice or tips on
the best route to become a major Airline Pilot as you are. I am
currently in the U.S. Air Force and I have been a Crew Chief for 8
years now. I never had much of an interest in airplanes until I began
working on them. I probably have more knowledge of flying (airport
ops, navigation, etc.).
I use my Microsoft Flightsim to learn more about
navigation, using my full set of
charts and aircraft gauges. I currently just have a high school
education, but I'm about 3 classes away from my associates degree. I
would like to take flying lessons but as I'm stationed in England, not
to mention my newborn baby, it's seemingly impossible right now. Well
that's enough about me. Basically I just have these few questions:
1. What education level is required, or preferred, to fly
the "big iron"?
2. Do most pilots start out flying small props to gain
flying hours, or do some Airlines offer a training program to start
you out on jetliners?
3. As I'm 27 now, does that somewhat hamper me because of
my late start?
4. Do you have just any general tips for me to follow to
achieve my newfound dream of becoming and airline pilot?
Nash Kenji SSgt
Hi Nash,
Since your email will be posted in my site, I would like to answer
your
question quite generally.
To be a pilot, a degree is preferable but not an absolute requirement.
It
depends on the Airline and the Cadet Pilot program is very competitive
and
usually the cream is selected just after the graduation from College
or
University. However, not all is lost if you do not meet the stringent
entry
requirements. Try and get yourself accepted as an Air Force
pilot to gain
experience. Your flying hours are usually recognized in civil
aviation.
Once you have accumulated sufficient flying hours, enroll yourself
into a
Commercial Pilot's License course first. When your term with the
Air Force
expires, you will most likely be ready to seek employment in the civil
sector as a co pilot in a multi-engined transport airplane. You
will have
to work your way from the bottom of the ladder but you will not regret
for
you will learn a lot on the right hand seat. Most major Airlines
are
unlikely to recruit pilots without an aircraft rating. The best
route is to
start off from the general aviation to build up your experience.
Most pilots start off from the Airline's Cadet Pilot program where
they
are specially trained in their particular training schools.
They commence
flying with the small single engine props and when they graduate from
the Training Schools, they are given further training by the Company
on the jetliners.
You are probably a bit late to join the Airline Cadet program at 27
years.
Alternatively, join a Flying Club and get your Private Pilot's
License.
Become an Assistant Flying Instructor in the Flying Club to build up
your flying hours and experience. If you work hard enough (you would
be paid as an Assistant Flying Instructor) you will achieve your
dream, though it may take a little longer.
Nothing is impossible!
Regards,
Capt Kay
