Dec. 18, 2018
An FAA Information for Operators (InFO) notice offers guidance about published all engines-operating (AEO) climb gradient requirements for IFR departure procedures and missed approaches that may prevent operators from applying excessive weight penalties and performance restrictions to departures in their aircraft.
InFO 18014 emphasizes that the published climb gradient for an instrument departure or missed approach is not a minimum value to maintain throughout the climb, but rather should be view as a surface to remain above on climbout. Pilots should consider the aircraft speed, thrust and configuration required to remain above that climb gradient surface until reaching the termination altitude. Review the full InFO.
The agency further cautioned that departure climb requirements established by terminal instrument procedure criteria and one engine inoperative (OEI) takeoff obstacle avoidance requirements for Part 121 and Part 135 operations differ.
Another potential source of misunderstanding is that manufacturers are only required to supply OEI takeoff performance data, not AEO. However, utilizing OEI data to determine compliance with published IFR climb gradients may lead operators to place excessive restrictions on the departure capabilities of their aircraft.
“These operators may artificially impose upon themselves performance requirements the FAA doesn’t deem necessary,” noted Rich Boll, chair of the ATC, Airspace and Flight Technologies Working Group of the NBAA Access Committee. “That may result in grossly restricting the performance and range capabilities of their aircraft.”
Boll added the InFO specifically notes the agency “imposes no requirement, nor is it recommending” that operators use FAA-approved OEI performance data to demonstrate compliance with IFR climb gradients. “Over the years, we’ve seen operators deny acceptance of SID based on their training or their assumptions of how to meet the climb gradient,” he added.
Rather than utilizing OEI data, the InFO encourages pilots to use AEO data prepared by the manufacturer or operator to determine whether or not the SID is usable at their operating weight. If AEO data is not available, pilots may calculate the rate of climb required to comply with the climb gradient based on the departing runway length and their anticipated ground speed on climbout, then conduct the departure in a manner to achieve that rate of climb.