March 3, 2007

 

 

Coby Johnson, Manager                                                

Flight Operations Branch, AFS-410

Federal Aviation Administration

800 Independence Ave., S. W

Washington, DC 20591

 

 

Dear Dr. Deuvall

 

In response to your presentation dealing with preflight takeoff calculations, runway analysis and obstacle clearance, I would like to take this opportunity to thank you for taking the initiative to shed more light on an area of aircraft performance that has accumulated a great deal of confusion over the years.

 

While the FAA can not endorse a specific product,  I can speak to the FAA’s position regarding the authority of the aircraft flight manual (AFM) in conducting preflight planning calculations.

 

First, allow me to dispel the notion that the AFM contains takeoff procedures that have been included for certification purposes only and have no operational relevance, particularly preflight planning. 

 

The profiles described within the AFM are considered by the FAA to be the only acceptable procedures. 

 

Second, if the AFM describes a takeoff path profile, including level-off or transition periods, engine time or other limits, those criteria must be considered when calculating appropriate engine inoperative obstacle clearance performance planning and weight restrictions.  This is particularly true for obstacles or gradients that extend above 1500 feet.

 

Third, the use of “rules of thumb”,  “work-a-rounds” or other methodologies not specifically described within the AFM or subsequently authorized by the manufacturer are not approved by the FAA.  This would include, but is not limited to, extrapolating performance values beyond the limits of a chart or substituting an enroute altitude for the airport elevation when entering a second segment chart.

 

While none of these clarifications diminish the pilot’s authority to deviate from any regulation to meet an in-flight emergency, the intent of this position is to improve the safety margin of all operations operated under commercial or general regulations. 

 

Again, whether you are presenting to Part 91, 135, 91k or 121 operators, please extend my appreciation for their continued efforts to improve their skills and knowledge as professional pilots.

 

Thank you

 

 

 

Coby Johnson

Manager, AFS-410