What must AF pilots departing from non-USAF airfields plan regarding crossing the DER?

When departing from non-USAF airfields, pilots must plan to cross the Departure End of the Runway (DER) at or above 35 feet. This altitude requirement is in place primarily for safety reasons, ensuring that aircraft have sufficient clearance over any potential obstacles in the departure path—especially since non-USAF airfields may not have the same obstacle clearance assessments as military airfields.

Crossing at or above this altitude helps to mitigate risks associated with terrain and obstructions in the vicinity of civilian airfields, where landscapes can vary considerably. The 35-foot requirement provides a buffer that enhances safety during the critical phase of takeoff and initial climb. Awareness of this altitude ensures pilots maintain a proper climb profile and adequately respond to any immediate conditions, such as adverse weather or malfunction.

The thresholds outlined in the other options either do not meet the minimum safety standards set forth for non-USAF airfield operations or they may reflect lesser-clearance standards that are not applicable in this context. Therefore, understanding the necessity and implications of this 35-foot requirement is crucial for effective flight planning and operational safety.