How do you interpret...

When filling IFR, there are two boxes you put numbers in, AIRSPEED and
TIME ENROUTE.

These go back to the old days, but are still applicable today.
AIRSPEED, as the name implies, tells ATC how fast your airplane is
going through the air.
TIME ENROUTE tells ATC when to expect you at your destination.

One of the regs says that you have to advice ATC of any airspeed
deviations of +/- 10% (someone correct me if I am wrong, I do not have
the AIM in front of me).
However, the TIME ENROUTE should take into account headwinds and/or
tailwinds. This is important in the event of loss of comm.

Here is the question:
When you fill in the AIRSPEED box, do you give the actual indicated
airspeed for your cruise power setting?
Or, do you use the "groundspeed", based on winds aloft?

If you use the actual indicated airspeed, the math is not correct for
the time enroute.

If you use the actual airspeed and the calculated no-wind time enroute,
you mess up the system in the event of loss of comm, since you will not
be where they expect you in the elapsed time.

Further, in these days of RADAR, LORAN and GPS, do you advice ATC of
the groundspeed deviation from the airspeed?

From the AIM: "Block 4: Enter your true airspeed (TAS)"

Don't sweat the details.

Bob Gardner

"EDR" wrote in message
...

When filling IFR, there are two boxes you put numbers in, AIRSPEED and
TIME ENROUTE.

These go back to the old days, but are still applicable today.
AIRSPEED, as the name implies, tells ATC how fast your airplane is
going through the air.
TIME ENROUTE tells ATC when to expect you at your destination.

One of the regs says that you have to advice ATC of any airspeed
deviations of +/- 10% (someone correct me if I am wrong, I do not have
the AIM in front of me).
However, the TIME ENROUTE should take into account headwinds and/or
tailwinds. This is important in the event of loss of comm.

Here is the question:
When you fill in the AIRSPEED box, do you give the actual indicated
airspeed for your cruise power setting?
Or, do you use the "groundspeed", based on winds aloft?

If you use the actual indicated airspeed, the math is not correct for
the time enroute.

If you use the actual airspeed and the calculated no-wind time enroute,
you mess up the system in the event of loss of comm, since you will not
be where they expect you in the elapsed time.

Further, in these days of RADAR, LORAN and GPS, do you advice ATC of
the groundspeed deviation from the airspeed?

TAS.
I always tell myself they need to know it for spaceing me between the big
boys.... just so I don't run them over. )
--
Jim Burns III

Remove "nospam" to reply

EDR wrote

Gee...EDR, you really disappoint me. :-)

One of the regs says that you have to advice ATC of any airspeed
deviations of +/- 10% (someone correct me if I am wrong,

Well, you asked for it! Advice is a noun. The word that you wanted
to use is advise, the verb.

When you fill in the AIRSPEED box, do you give the actual indicated
airspeed for your cruise power setting?

Nope! You use TAS, which is CAS corrected for pressure altitude and
temperature. Hmmm....how do you get from IAS to CAS???? :-)

If you use the actual indicated airspeed, the math is not correct for
the time enroute.

Of course, if you are using indicated airspeed, the math isn't correct
anyway.

If you use the actual airspeed and the calculated no-wind time enroute,
you mess up the system in the event of loss of comm, since you will not
be where they expect you in the elapsed time.

If you have "advised" ATC of a change in TAS, they recompute your ETA.


Further, in these days of RADAR, LORAN and GPS, do you advice ATC of
the groundspeed deviation from the airspeed?

EDR....you really aren't a pilot are you?

Bob Moore
ATP CFI

Robert Moore wrote:


If you have "advised" ATC of a change in TAS, they recompute your ETA.

ATC does no such thing. You tell a controller that you are going 20
knots slower/faster than you put on your flight plan the controller
could not possibly care less. In one ear and out the other.

"Newps" wrote in message
news:aqnLb.1278$na.1288@attbi_s04...


Robert Moore wrote:


If you have "advised" ATC of a change in TAS, they recompute your ETA.

ATC does no such thing. You tell a controller that you are going 20
knots slower/faster than you put on your flight plan the controller
could not possibly care less. In one ear and out the other.

Probably the only person who will care if you don't announce it is the DE on
your instrument checkride. And I don't think they will care very much. (I
did it on my checkride because I slowed to Va (not Vb) for turbulence).

-- David Brooks

In article aqnLb.1278$na.1288@attbi_s04, Newps
wrote:

Robert Moore wrote:


If you have "advised" ATC of a change in TAS, they recompute your ETA.

ATC does no such thing. You tell a controller that you are going 20
knots slower/faster than you put on your flight plan the controller
could not possibly care less. In one ear and out the other.


Don Brown, according to his column today, seems to pay attention to such
details.

http://www.avweb.com/news/columns/186442-1.html

"Craig Prouse" wrote in message
...
| In article aqnLb.1278$na.1288@attbi_s04, Newps
| wrote:
|
| Robert Moore wrote:
|
|
| If you have "advised" ATC of a change in TAS, they recompute your ETA.
|
| ATC does no such thing. You tell a controller that you are going 20
| knots slower/faster than you put on your flight plan the controller
| could not possibly care less. In one ear and out the other.
|
|
| Don Brown, according to his column today, seems to pay attention to such
| details.
|
| http://www.avweb.com/news/columns/186442-1.html

Don Brown's gripe appears to be about what he was handed from other sectors,
not about what airspeed the pilot reported.

Correct me if I am wrong, but I thought you only reported a change in
airspeed or ETA if you were in a non-radar environment?

My instructor told me I had to report change in airspeed regardless. I
found this in the AIM:

Section 3. En Route Procedures

5-3-1. ARTCC Communications

snip

5-3-3. Additional Reports

a. The following reports should be made to ATC or FSS facilities
without a specific ATC request:

1. At all times.

(a) When vacating any previously assigned altitude or flight
level for a newly assigned altitude or flight level.

(b) When an altitude change will be made if operating on a
clearance specifying VFR-on-top.

(c) When unable to climb/descend at a rate of a least 500 feet
per minute.

(d) When approach has been missed. (Request clearance for
specific action; i.e., to alternative airport, another approach, etc.)

(e) Change in the average true airspeed (at cruising altitude)
when it varies by 5 percent or 10 knots (whichever is greater) from that
filed in the flight plan.



FWIW

----------------------------------------------------------


"C J Campbell" wrote in message
...

"Craig Prouse" wrote in message
...
| In article aqnLb.1278$na.1288@attbi_s04, Newps
| wrote:
|
| Robert Moore wrote:
|
|
| If you have "advised" ATC of a change in TAS, they recompute your
ETA.
|
| ATC does no such thing. You tell a controller that you are going 20
| knots slower/faster than you put on your flight plan the controller
| could not possibly care less. In one ear and out the other.
|
|
| Don Brown, according to his column today, seems to pay attention to such
| details.
|
| http://www.avweb.com/news/columns/186442-1.html

Don Brown's gripe appears to be about what he was handed from other
sectors,
not about what airspeed the pilot reported.

Correct me if I am wrong, but I thought you only reported a change in
airspeed or ETA if you were in a non-radar environment?

"C J Campbell" wrote in message
...

Correct me if I am wrong, but I thought you only reported a change in
airspeed or ETA if you were in a non-radar environment?


The AIM says to report at all times a change in the average true airspeed
(at cruising altitude) when it varies by 5 percent or 10 knots (whichever is
greater) from that filed in the flight plan.