AF Form 3993: Instrument Procedure Flyability Check (DP)

AF Form 3993: Instrument Procedure Flyability Check (DP) – AF Form 3993: Instrument Procedure Flyability Check – Departure Procedures (DP) is a specialized U.S. Air Force form used to document and validate the safety, practicality, and operational suitability of Departure Procedures (DPs) before they are flown in instrument meteorological conditions (IMC) or under IFR.

This form supports USAF aircrew and instrument procedure validation processes, helping ensure that published or proposed departure procedures align with aircraft performance, obstacle clearance requirements, and standard operating procedures.

What Is AF Form 3993?

AF Form 3993 (also referred to as AF IMT Form 3993) is titled “Instrument Procedure Flyability Check – Departure Procedures (DP).” It serves as the companion to AF Form 3992 (used for Instrument Approach Procedures/IAPs). While AF Form 3992 focuses on approaches, AF Form 3993 specifically evaluates departure procedures.

Departure Procedures (DPs) include:

  • Obstacle Departure Procedures (ODPs) — Textual or graphic procedures designed to provide obstacle clearance during the initial climb after takeoff.
  • Standard Instrument Departures (SIDs) — ATC-routable procedures primarily for traffic flow and system efficiency, which may also include obstacle considerations.
  • Diverse departures (when a runway passes a 40:1 obstacle assessment, allowing turns in any direction while maintaining a standard 200 ft/NM climb gradient after crossing the departure end of the runway (DER) at 35 feet and climbing to 400 feet AGL).

The form captures real-world flight data from a flyability check—a practical evaluation flight (not an official FAA flight inspection) conducted to verify that the procedure is safe, flyable with the assigned aircraft, and consistent with good airmanship.

Purpose of the Instrument Procedure Flyability Check for Departures

USAF policy requires flyability checks to confirm that instrument procedures are:

  • Safe and free of unexpected hazards.
  • Practical for the specific aircraft type and mission.
  • Consistent with published TERPS (Terminal Instrument Procedures) criteria and Air Force guidance.

For departures, this is critical because the initial climb phase offers limited time and altitude to react to obstacles, terrain, or performance issues. Checks help identify issues with climb gradients, turn points, navigation aids, or aircraft-specific handling before general use by operational crews.

Key references include:

  • AFMAN 11-230 (Instrument Procedures) — Provides instructions for completing AF IMT 3993 (Attachment 8 in older editions).
  • AFMAN 11-217 (Instrument Flight Procedures) — Covers IFR departure planning, obstacle clearance surfaces (OCS), and flyability checks.
  • AFMAN 11-202 Volume 3 (Flight Operations) — General flight rules governing IFR operations.
  • FAA Order 8260.46 (Departure Procedure Program) and related 8260-series forms used in procedure development.

Military DPs are managed differently from civil ones; approval authority rests with the military, and coordination with the FAA is required when procedures affect the National Airspace System (NAS). NGA publishes military DPs.

When Is AF Form 3993 Used?

  • When validating new, revised, or host-nation departure procedures before publication in DoD FLIP (Flight Information Publications).
  • As part of Foreign Terminal Instrument Procedures (FTIP) reviews for non-U.S. government procedures.
  • When aircrews identify potential discrepancies in published DPs and a practical check is needed.
  • In support of MAJCOM or unit-level instrument procedure validation programs (e.g., AMC units reference it in AMCI 11-208 for feedback on Giant Report airfield data).

Flyability checks are typically performed by instructor or evaluator pilots whenever possible and should include the full relevant segments of the procedure. They supplement (but do not replace) official TERPS design and flight inspection processes.

How to Complete AF Form 3993?

Although the official PDF is available for download from the Air Force e-Publishing site, the form generally captures:

  • Header information: Date, location/airfield, runway, aircraft type/MDS, crew details, and procedure name (e.g., specific SID or ODP).
  • Procedure details: Description of the DP being checked, including any required climb gradients, altitudes, routes, and navigation requirements.
  • Equipment and conditions: Aircraft instrumentation used, weather conditions, and any special equipment notes.
  • Flyability assessment: Pilot observations on workload, aircraft performance vs. required climb gradient (noting USAF emphasis on one-engine-inoperative performance for multi-engine aircraft where applicable), obstacle clearance, navigation accuracy, and overall practicality.
  • Results and recommendations: Pass/fail determination, discrepancies noted, suggested changes, and signatures from the evaluating pilot and approvers.
  • Remarks section: Any additional comments on human factors, cockpit resource management, or compatibility with specific aircraft systems.

Detailed block-by-block instructions are provided in the relevant AFMAN 11-230 attachment (historically Attachment 8). Always refer to the current version of the form and associated instructions on e-Publishing.af.mil.

Download the official AF Form 3993 here: https://static.e-publishing.af.mil/production/1/af_a3/form/af3993/af3993.pdf

  • Climb Gradient Planning: USAF pilots must ensure aircraft performance meets or exceeds the higher of 200 ft/NM, MAJCOM-directed values, published DP requirements, or flight manual limits. Multi-engine aircraft often compute using OEI assumptions. Limited waivers (e.g., subtracting up to 48 ft/NM in some cases) may apply under mission authority.
  • Diverse Vector Area (DVA): Used when vectoring below MVA/MIA; evaluated using 40:1 obstacle assessment.
  • Procedure Problem Reporting: Aircrews should report issues via appropriate channels so they can be corrected through NOTAMs or procedure amendments.
  • IFR Departure Planning Steps (per AFMAN 11-217 guidance):
    1. Select valid departure method (Diverse, ODP, SID, or vectors).
    2. Determine required climb gradient.
    3. Verify aircraft performance meets the gradient.
    4. Review notes in the IFR Takeoff Minima and Departure Procedures section of IAP books.

Why Flyability Checks Matter for USAF Operations?

Safe IFR departures are foundational to mission success. A properly executed flyability check documented on AF Form 3993 reduces risk by confirming that procedures work as intended in the real world with USAF aircraft and crews. This is especially important at airfields with challenging terrain, non-standard procedures, or when operating aircraft with unique performance characteristics.

For the latest instructions, always consult current editions of:

  • AFMAN 11-202V3
  • AFMAN 11-217 series
  • AFMAN 11-230
  • Your MAJCOM supplements

Download AF Form 3993 directly from the official source linked above and ensure you follow the most recent Air Force guidance for instrument procedures.

This article is for informational purposes and to assist U.S. Air Force personnel and aviation professionals. Always refer to official e-Publishing documents and current MAJCOM directives for compliance.