Takeoff Performance Estimator
AirSmith, LLC

User Guide

A short introductory video showing the use of this application is available at http://www.youtube.com/watch?v=pOT_aSaZPuc

 INFORMATION

By tapping the Information icon on the Home Screen, the user will be presented with detailed instructions regarding the Aircraft Library, Takeoff Data, and the Takeoff Summary screens.

Tapping on a topic in the Table of Contents will present the user with information regarding that specific topic, and taping (top), will return the user to the Table of Contents. Tapping the HOME key on the Navigation Bar will return the user to the application Home Screen.

 



 

AIRCRAFT LIBRARY

This facility stores the aircraft information used to derive the estimated takeoff distance.  Herein, the user can create and later select aircraft data to be used in the takeoff.  The user can also edit and delete aircraft information.

 








TO ADD AN AIRPLANE

To add an airplane, tap the AIRCRAFT LIBRARY icon on the Home Screen. On the Library Screen, tap EDIT. From this EDIT screen, the user can employ the standard Apple icons and gestures to ADD, DELETE, or MODIFY an aircraft. After tapping the ADD icon, the user will be presented with a screen where the user can enter the data used by the application to create the takeoff distance estimates for that aircraft.

The first two fields are alphanumeric and use the standard iPhone Keyboard. These two fields will appear in the library contents listing when you tap the Aircraft Library Icon on the Home Screen for subsequent aircraft selection.

 



The NEXT key advances the input cursor to the next alphanumeric field (from “Tail Number” to “Type”). After entering the Aircraft Type (plus an optional 5 additional optional characters), the cursor will advance to the Gross Weight field. When the cursor is on this field the Application Keyboard is presented for the balance of this operation. The "POH Tables?" field is a "YES/NO" switch to tell the system if the aircraft’s POH uses table or graphs to present takeoff performance information.

Each tap of the NEXT key, on either keyboard, will advance the cursor to the next field.  If the user needs to return to a previous field, tapping on that field will return the cursor to that field’s typing position.  If a value is already in the field, the cursor will appear at the end of the last typed entry.

 

 THE APPLICATION KEYBOARD

The application keyboard allows for quick and convenient data entry for all the numeric entries. There are the ten digits from 0 to 9, a NEXT key and a BACKSPACE icon (in the lower right position).  The BACKSPACE key allows the user to revise an entry in a particular field. 

The user will note that there is no decimal point on the keyboard.  The decimal point is fixed in each field.  One or two decimal points may be required, depending on the field. The user will know this by the number of “0s” after the decimal point in a particular field.  . 

For example, when the user sees “0.0,” that queues that the last numeral entered will be after the decimal.  Likewise “0.00” queues the user that the last two numerals entered will be after the decimal. For example, on a field with one decimal point, entering “2” will equal “0.2” and entering 2-0 will equal 2.0.  On a field with two decimal points, 1-2-3 will equal 1.23, while 1-2-3-4 will equal 12.34.  

For each aircraft, the required information is:

TAIL NUMBER

This is the aircraft registration number.  This entry will appear in the Library selection listing, along with the aircraft type.

TYPE:

The aircraft type, such as C-172N.  An additional 5 characters is available for any informal (for example, enter “glass” for an aircraft in the library with a glass cockpit).

POH Tables: YES/NO

This selector tells the application whether the Aircraft’s Pilot Operating Handbook uses tables or graphs to represent takeoff information.   If TABLES is set to YES, the application will ask for the wind correction factors that exist in the Notes section of the Tables.  The default is YES.  It may be changed by the user by tapping on the “POH Tables?” switch icon.

GROSS WEIGHT

This is the maximum takeoff weight prescribed in the Aircraft Limitations Section of the Pilot Operating Handbook (POH).  It is not the Maximum Ramp Weight, which, in some aircraft POHs, is listed separately.

“NO OBSTACLE” TAKEOFF DISTANCE REQUIRED

Often LISTED under Takeoff Performance and called the Takeoff Ground Roll or Takeoff Run, this is the required distance to lift off from the runway at gross weight, at the prescribed takeoff speed, at ZERO density altitude, or Sea Level at Standard Temperature (15 C).  Use the numbers in the POH, not what personal experience may dictate.    

“50 FOOT OBSTACLE” TAKEOFF DISTANCE REQUIRED

Often listed under Takeoff Performance and stated in POHs, this is the ground roll distance plus the distance required to ascend to 50 feet (15 meters).  Use the figures in the POH for gross weight and Sea Level, at Standard Temperature (15 C).  Use the numbers in the POH, not what personal experience may dictate.

LOWEST CHARTED DISTANCE

At the user’s discretion, this entry represents the lowest distance the system will report under any circumstances.  This may represent the user’s personal minimums or the lowest takeoff performance ground roll that can be found in the POH.  Under extreme temperatures conditions, the calculations can report some very short takeoff distances.  Under no circumstances will the application return a lesser distance than this entry. This capability allows the user to create a minimum, safe takeoff distance within the system. 

LIFT OFF SPEED

Enter the lift off speed (from the runway, rather than upon reaching the obstacle clearance height) of the aircraft, at gross weight under standard conditions.

HEADWIND FACTOR FROM THE POH (percentage change in the distance)

This is the percentage decrease in the required distance for headwind.  For example, if the notes in the POH say, “Decrease distances 10% for each 9 knots of headwind.” Enter 10 in this field.

HEADWIND FACTOR FROM THE POH (per ___ knots of headwind)

This is the number of knots that correspond to the percentage change in distance.  For example, if the notes in the POH say, “Decrease distances 10% for each 9 knots of headwind.” Enter 9 in this field.

TAILWIND FACTOR FROM THE POH (percentage change in the distance)

This is the percentage increase in the required distance for tailwinds.  For example, if the notes in the POH say, “Increase distances 10% for each 2 knots of tailwind.” Enter 10 in this field.

TAILWIND FACTOR FROM THE POH (per ___ knots of headwind)

This is the number of knots that correspond to the percentage change in distance.  For example, if the notes in the POH say, “Increase distances 10% for each 2 knots of tailwind.” Enter 2 in this field.

WING SPAN

This can be found in the Aircraft Description Section of the POH.  It is the measurement from wing tip to wing tip.  This number and the following number will be used to calculate the Aspect Ratio of the aircraft.  The aspect ratio, or the ratio of the wing area to the span, is used by the application to calculate the effects of density altitude on the performance of the aircraft.  High-aspect ratio aircraft react differently to higher density altitudes than low-aspect ratio aircraft. 

WING LOADING

Wing loading is also provided in the POH under the Aircraft Description Section or on the Performance and Specifications Page in the front of the POH.  Most aircraft POHs provide this information, however, some only report the calculated area of the wing. 

To calculate the appropriate value when only the wing area is available, divide the takeoff gross weight by the wing’s area.  For example, an airplane with a gross weight of 3100 pounds and a wing area of 174 square feet, the wing loading is 17.82.  Enter that result in the WING LOADING field.

SAFETY FACTOR

If this field is left blank, the application will report the distance required when accounting only for the effects of the prevailing conditions.  At the user’s discretion, the percentage entered herein will be added to the calculated takeoff estimate.  With no entry in this field, there will be no consideration for aircraft’s condition, conformance to the test environment used to derive the takeoff data in the POH, or aerodynamic inefficiencies associated with crosswind control displacement.  Recall that the POH distances are often for short field takeoff procedures.  These procedures are not often used under average conditions, and appropriate adjustments must be considered. 

The user is reminded that adding 50% to the takeoff distance required is a common practice.

This practice would accommodate variances in technique, aircraft condition, and increases the chances of a safe rejected takeoff, should an anomaly be recognized early in the procedure. Furthermore, many aircraft Pilot Operating Handbooks quote takeoff performance based on Short Field techniques, and the results of this estimator are ultimately based on those distances.  

If the user wishes to have the application report the takeoff run plus a safety margin, enter that margin in this field.  If the user wishes to have the application report the minimum runway requirement rather than the takeoff distance, use 50%, plus the desired margin, as the Safety Factor entry. 

SAVE AIRCRAFT

When the user completes the last step, tap the SAVE key.  A confirmation option is presented.  The user can tap YES to save the information or CANCEL to return to the data entry screen to audit the entries for accuracy.   All the entries will be displayed for a final review.  THIS DATA MUST BE ACCURATE.  When the user is satisfied that the data is accurate, the user taps SAVE. When the user taps SAVE, the system will return to the EDIT screen.  If there are no more library maintenance tasks to perform, the user taps HOME.

UNITS

The application is “units agnostic” except on the screens specifically labeled with the required units of measure. These are the Temperature entry (needs to be Centigrade), and the Obstacle Height entry (needs to be FEET).  If metric units are used, they must be consistently used save for the previously mentioned exceptions.  If metric units are to be used, all weights, including wing loading, must be in kilograms.  All lengths, including wing span (meters) and lift off speed (kilometers per hour), must be metric.  If English units are to be used, all weights, including wing loading, must be in pounds. All lengths, including wing span (feet) and the lift off speed (knots), must be English units.

FAILURE TO USE PROPER UNITS OF MEASURE FOR “TEMPERATURE” AND “OBSTACLE HEIGHT WILL CAUSE SERIOUS ERRORS. OBSTACLE HEIGHT MUST BE ENTERED IN FEET, NOT METERS.  ENTERING THIS HEIGHT IN METERS (15 METERS) INSTEAD OF FEET (50 FEET) WILL RESULT IN A GROSS UNDERSTATEMENT OF THE TAKEOFF DISTANCE.

TAKEOFF DATA

This is the facility used to enter the prevailing conditions for takeoff.  The application will calculate the effect on takeoff performance created by the difference between the standard conditions performance data from the Aircraft Library, and the prevailing conditions entered here.

AIRCRAFT SELECTION

This process begins by selecting an aircraft from the Aircraft Library.  In the Aircraft Library, the user can use standard iPhone swipes and gestures to manage the library. To select an aircraft, enter the Aircraft Library and tap on the desired aircraft.  











The user will be presented with a summary of the aircraft information from the library, which can be used to verify the selection.  At the bottom of this screen, there is a shortcut to the first screen in the Takeoff Data facility.  At the top of this screen is a navigation button back to the Aircraft Library.

The user will note that each screen in the Takeoff Data facility contains a navigation button in the upper left that allows for return to the previous screen.  The NEXT button on the Application Keyboard allows for advancing to the next field or screen.  These two functions permit navigation throughout the Facility.

The data entered here will stay in the system until it is overwritten by new data.  This allows for quick updates to the system as the prevailing takeoff conditions change.  If the user changes to a different aircraft after entering the prevailing conditions, the prevailing conditions will NOT change.  Therefore, after changing the aircraft, the user should review the prevailing conditions, and assure they are current and within the limits of the newly selected aircraft. 

 DENSITY ALTITUDE

Upon tapping the Takeoff Data Icon on the Home Screen, the user is presented with the DENSITY ALTITUDE Screen.  Here, the user enters the pressure altitude for the takeoff, and the temperature. These two entries will be used to calculate the prevailing density altitude. The pressure altitude is the field elevation corrected for non-standard barometric pressure.  The user will recall that the pressure altitude is found by subtracting the station sea level pressure from 29.92, multiplying that result by 1,000 and adding that figure to the field elevation.  For example, if the sea level pressure is 30.92 and the field elevation is 2500 feet, the pressure altitude is approximately 1500 feet.

The NEXT key advances to the field where the temperature, in degrees Centigrade, is entered.  There is no provision to enter negative temperatures in this field. 

TAKEOFF WEIGHT

The NEXT key will advance to the Takeoff Weight Screen.  The user enters the Takeoff Weight using the appropriate units of measure.  While the entry is being made, the application will calculate the percentage of gross weight that the entry represents.  If the entry exceeds 100% of the Gross Weight for that aircraft, the system will present an OVERWEIGHT annunciation and halt. The system will not advance to the next screen until the OVERWEIGHT condition is resolved.

NOTE: SHOULD THE USER CHANGE THE AIRCRAFT AFTER THESE ENTRIES, IT IS IMPERATIVE THAT THE USER REVIEW THE TAKEOFF WEIGHT TO ASSURE IT IS WITHIN LIMITS FOR THE NEW AIRCRAFT.



WIND

This screen contains two fields where the wind speed and direction are entered.  If there is a calm wind, no entry is required and the system will enter a “0” when the NEXT key is tapped. 

WIND DIRECTION

Enter the three-digit MAGNETIC wind direction.  This value will be compared to the runway designator to derive the head/tail/cross wind components.

            RUNWAY

The user enters the runway designation in this field.  Only two digits are valid for this screen.  The NEXT key will advance the user to one of two screens.  If wind speed has been entered, the NEXT key will advance to the Wind Components Screen.  If there is no wind speed entered, the NEXT key will advance to the OBSTACLE HEIGHT Screen.

 

 

 

THE WIND COMPONENTS GRAPHIC

If there is no wind speed entered, the user will not be presented with this graphic. If a wind speed has been entered, the user will be presented with a graphic that shows the relationship of the wind direction to the selected runway.  The user will be able to observe the crosswind component, the headwind/tailwind component, and the total wind.  The “Runway” navigation button in the upper left corner is available to return to the Runway Screen to select a different runway, if desired.  Note the NEXT key on this screen is in the upper right corner. 

 





OBSTACLE HEIGHT

Enter the obstacle height (sometimes called the “screen height”) in FEET. 

OBSTACLE HEIGHT MUST BE ENTERED IN FEET, NOT METERS, REGARDLESS OF THE UNITS OF MEASURE USED ELSEWHERE IN THIS APPLICATION.  ENTERING THIS HEIGHT IN METERS (15 METERS) INSTEAD OF FEET (50 FEET) WILL RESULT IN A GROSS UNDERSTATEMENT OF THE TAKEOFF DISTANCE.



 

 

 

RUNWAY GRADIENT

Enter the runway gradient as a percentage, and select if the gradient is “Uphill” or “Downhill”.  This information is generally available in the airport information for the intended takeoff.

The NEXT key from this screen will take the user to the Takeoff Summary Screen.

 

 

 

 

 

 

TAKEOFF SUMMARY

There are two Takeoff Summary Screens, one in the vertical orientation of the iPhone, and the other in the horizontal orientation of the iPhone.

The vertical orientation presents the following:

  1. The Tail Number of the Aircraft used in the distance estimates
  2. The Results of the Density Altitude Calculation.
  3. The estimate of the distance required to complete the takeoff, either ground roll or over the obstacle.
  4. The contaminated surface estimates, adding 7% to the distance required for Turf, 10% for short grass, 25% for tall grass, and 50% for soft fields or mud.  It should be noted that these commonly accepted estimates can be used in lieu of safety factors, if the Safety Factor field was left blank in the Aircraft Library.
  5. The head/tail/cross wind vectors.

The vertical orientation also presents a Navigation Key back to the Home Screen to reselect a different aircraft or end the operation.  There is also a Navigation Key to navigate back to the Takeoff Data, should the user want to make last minute changes or select a different runway. 













The horizontal orientation presents the data in the vertical orientation, as well as the salient information entered by the user about the takeoff.  That information is:

  1. The pressure altitude input.
  2. The temperature input.
  3. The takeoff weight.
  4. The obstacle height.
  5. The runway in use.
  6. The wind direction.
  7. The wind speed.

Returning the device back to the vertical orientation will reveal the navigation keys.  The Takeoff Summary can also be accessed directly from the Home Screen by tapping the Takeoff Summary icon.

Disclaimer:  14CFR 91.3 states that the Pilot in Command is responsible for the safety of flight.  Airsmith, LLC has made every reasonable effort to ensure the accuracy of its calculations.  Airsmith, LLC cannot absolutely guarantee the accuracy.  By using this product, you agree to hold harmless Airsmith, LLC, its agents or assigns, for any and all liability, bodily injury, or property damage arising out of the use of this product.

Takeoff Performance Estimator™ and all associated digital content is a product of AirSmith, LLC. All rights reserved.

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