eTold Help Page
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Last updated Oct 9, 2011
etold is a program that calculates the required performance data as
specified in the Airplane Flight Manual (AFM) Performance Charts. As you
change the configuration or conditions, the resulting data changes.
If internet access is available, the program also retrieves data
about the airport (runway data, etc.) as well as weather data
(TAF and METARs) for the desired airports from the
All data used in calculations can be overridden as desired. For
instance, if you think that the temperature at the time of
departure will be differnet from the current METAR, you can override
the temperature that the program retrieved from the METAR.
The program attempts to parse the weather data from the METAR, however,
if the METAR format is in error, the program may not be successful.
In this case, the raw METAR is displayed so that you can interpret
the various data needed for the calculations.
The program has:
The following menus are available. Note that the Windows version does not support
initiating phone calls or email because of the large variety of system
configurations and so the phone numbers and emails will be displayed for manual use.
- Swap Departure and Arrival - Swap the airports. This is useful
even if you are not returning directly to the departure airport. Although the arrival
airport won't be useful, chances are you'll be departing from the airport to which you
- Dial FSS - Initiate a call to Flight Service Station at 800-992-7433.
- Dial Clearance Delivery - Initiate a call to Clearance Delivery at 888-766-8267.
- Preferences - Allows you to specify the departure and arrival airports to be used
when the program starts. This screen is also used for typing in the license key for a registered
- Help - contains several sections:
- - Abbreviated help, primarily notes from the AFM concerning runway contamination.
- - The last performance calculation parameters to be sent to support if you suspect
that the performance calculation is in error.
- - The last METAR received by etold
- - The last TAF received by etold
In the smart phone versions, the performance, METAR, and TAF may be conveniently emailed to
support. During the mailing process, you will have a screen available to note the
circumstances of the error.
For the Windows version, you can copy and paste the information into an email message.
- About - Program author and version screen.
- Find Airport - etold will access the internet to try to find the desired airport data,
that is, runways, directions, and lengths.
- Recalc - etold will request new METAR and TAF data from the internet and parse the METAR
data to update the various screen weather data items to the new values.
- Refresh - etold will request new METAR and TAF data from the internet but not
update the screen weather data items. This is useful if you've overriden any of the weather
data on the screen.
Departure and Arrival Weather
Note that the Departure Weather screen and the Arrival Weather screen are identical.
- Airport ID - The airport to be used for performance and weather. For ICAO airports you
must the first letter in the US must be a "K". For non-ICAO airports (typically
containing a digit as one of the ID characters), you must not use a "K".
- MSL - The elevation of the airport
- Wind Dir - the current wind direction based on the METAR.
- Wind Speed - the current wind speed based on the METAR.
For gusty winds, 1/2 of the gust factor will be included in this number
- TempC - the airport reported temperature in C based on the METAR.
- Baro - the altimeter based on the METAR. This may be specified in inches (like 29.92) or in
millibars like (1013).
- Rwy Dir - the direction of the runway selected. For instance, runway 12R would be specified as '120'.
- Length - the length of the runway. For departure, etold uses ASDA (accelerate-stop distance available). For
arrival, LDA (landing distance available) is used.
- Slope - The slope of the runway, a negative slope (in percent grade) is lower at the far end than the near end.
Currently the airport database does not return this datum so
you must fill this in manually.
- Hdwind - This value is calculated based on the runway direction, the wind direction, and wind speed based
on the "Wind Speed" value which by default includes 1/2 of the gust factor.
- Runway select - This pull-down allows you to select from the list of available runways and
lengths as returned from the airport internet database.
- Contamination - This pull-down allows you to select the runway contamination as specified in the AFM
- De-Ice - Selects what de-ice equipment is being used for the performance calculation as specified in the AFM
- Anti-Skid - Selects whether the anti-skid is active (ON) or disabled (OFF).
- Reversers - Selects the type of engine nozzle for the power calculation.
- METAR - The METAR as reported by the nws.noaa.gov website.
The header also contains the time of the data access as well.
- TAF - The TAF as reported by the nws.noaa.gov website. Note that if
the airport you want does not have a TAF, etold will try to find an airport nearby with a TAF and display that
airport TAF with 'nearby' in the header. The header also contains the time of the data access as well.
- Emg Dump - How much fuel to dump to reduce your takeoff weight to the max landing weight. On some of the
smart-phones you can double-tap or long-tap to clear this value.
- Emg Vref - The Vref applicable to your takeoff weight minus the dump weight. This calculation should
be accurate even if you are landing overweight possibly because you've zero'ed the 'Emg Dump' entry.
- Emg Dist - The landing distance required as specified by the AFM as
applicable to your takeoff weight minus the dump weight.
Again, this calculation should be accurate even if you are landing overweight.
- Runway - The length of runway as specified in the 'Length' item of the weather screen.
- RwyReq - The ASDA length of runway required for the operation
- WtLim - This shows the maximum takeoff weight. If this weight is less than the maximum gross
takeoff weight, the weight is specified by the weight-limit performance charts.
- TotWt/slider - This allows you to select the takeoff weight, either by typing in the weight, or
by moving the slider back and forth.
- N1 - The proper power setting for takeoff
- V1 - The 'go anyway' speed as specified in the AFM.
- Vrot - The rotation speed as specified in the AFM.
- V2 - The initial climb speed as specified in the AFM.
- Vfs - The speed at which takeoff flaps can be removed as specified in the AFM.
- Vse - The proper single-engine climb speed once a safe altitude has been reached (usually 1500agl).
- ClbGrad 1eng - The single-engine climb gradient you can expect at the airport elevation
as specified in the AFM.
- Flaps - Allows you to select the desired takeoff flap setting.
- FAR - allows you to specify the regulations under which you will be landing:
- Part 91 - non-commercial operation reflecting the capability of the aircraft as specified in the AFM
- Part 135 - normal commercial operation - the landing must be completed to a stop within 60% of the
required runway length as specified in the AFM.
- Part 135-lo-viz - For low visibility operations (visibility less than 4000RVR or 3/4 mi),
the regulations require 15% more than the normal commercial operation length.
- Flaps - allows you to specify the flaps to be used for the landing data calculation
- VREF - the calculated VREF as specified in the AFM
- Runway - the runway length as specified on the weather screen
- RwyReq - the runway required as per the AFM including any extra distance required
by the regulations governing the operation.
- MxLdg - This shows the maximum landing weight. If this weight is less than the maximum gross
landing weight, the weight is specified by the AFM landing weight-limit performance charts.
- LdgWt - This shows the landing weight as resulting from the takeoff weight as specified on the
Departure Vs Data screen minus the fuel burn
- FuelBurn/Slider - This allows you to select the fuel burn, either by typing in the weight of the
burn, or by moving the slider back and forth.
- Go-Around - the items below this text apply to a missed approach go-around
- PwrN1 - The AFM specification for the power setting for takeoff based on the airport elevation
- Vapr1Eng - The AFM specification for the speed for a single-engine climb resulting from a missed approach
- Vldg2Eng - The AFM specification for the speed for a two-engine climb resulting from a missed approach
- VaprGrad - the climb gradient as specified in the AFM from a single-engine climb after a missed approach