IFR Cross-Country Planning: From Flight Plan to Filed Route

What does IFR cross-country planning involve?

IFR cross-country planning is the structured process of turning a destination into a legal, safe, filed flight — from initial weather analysis through departure briefing. The regulatory backbone lives in 14 CFR 91.103, which requires every pilot in command to "become familiar with all available information concerning that flight" before departure. For IFR flights specifically, that includes weather reports and forecasts, fuel requirements, and alternatives available if the planned flight cannot be completed.

The planning process breaks into several sequential workstreams:

• Weather analysis — METAR, TAF, AIRMET, SIGMET, PIREP, and area forecasts
• Route selection — preferred routes, airways, RNAV direct, and ATCSCC initiatives
• Alternate planning — applying the 1-2-3 rule and 91.169(c) weather minimums
• Fuel planning — computing the 91.167 requirement with an example calculation
• Flight plan filing — ICAO format fields and what ATC does with them
• Departure briefing — DP analysis, clearance expectations, lost-comm procedures
• Enroute planning — MEAs, MOCAs, OROCAs, and altitude rule compliance
• Arrival and approach preparation — STARs, approach selection, missed approach

Each workstream is covered in its own section below, with the FAR citation that governs it. DPEs regularly open the oral exam with broad cross-country planning scenarios, so understanding the regulatory framework behind every decision — not just the mechanics — is what separates a passing candidate from a failing one.

How do you analyze weather for an IFR flight?

Weather analysis for an IFR flight begins with the products listed in AIM Chapter 7 and available at the FAA Aviation Weather Center (aviationweather.gov). The goal is to build a complete picture of conditions at departure, along the route, and at the destination and alternate — not just at the moment of departure but through the entire planned flight time.

A systematic weather review follows this hierarchy:

• METAR — Current surface observations reported every hour (special METARs issued on significant changes). Provides wind, visibility, ceiling, altimeter, and present weather at a specific airport.
• TAF — Terminal Aerodrome Forecast covering 24–30 hours in a 5 sm radius. The primary product for destination and alternate planning; the 1-2-3 rule (14 CFR 91.169) references forecast conditions, not current observations.
• AIRMET — Advisories for conditions that may affect aircraft safety but don't meet SIGMET criteria. Sierra (IFR conditions and mountain obscuration), Tango (moderate turbulence and low-level wind shear), and Zulu (moderate icing) are the three types.
• SIGMET — Significant meteorological information for conditions hazardous to all aircraft: severe/extreme turbulence, severe icing, dust/sandstorms, volcanic ash, and tropical cyclones. Not convective-specific; convective SIGMETs cover embedded thunderstorms, severe thunderstorms, and tornadoes.
• PIREP — Pilot weather reports filed by other aircraft operating in the same airspace. The most timely source of actual icing and turbulence data; required to be filed when requested by ATC or FSS.
• Graphical Forecast for Aviation (GFA) — Available at aviationweather.gov, the GFA integrates ceiling, visibility, precipitation, turbulence, and icing forecasts into a single graphical interface covering the contiguous United States.
• Prog Charts — Prognostic charts showing fronts and pressure centers at 12, 24, 36, and 48-hour intervals. Useful for identifying frontal boundaries and areas of expected IFR conditions along the route.

The practical workflow is to start with the big picture (prog charts, GFA), then zoom into route-specific products (AIRMETs, SIGMETs), and finally evaluate the destination and alternate using TAFs. A DPE will expect you to explain not just what each product shows but how you used it to make a go/no-go decision.

What weather products are required before an IFR flight?

14 CFR 91.103(a) requires a PIC to review "weather reports and forecasts" for any IFR flight or any flight not in the vicinity of an airport. The regulation does not enumerate specific products — it establishes a standard of care. The AIM, which the FAA describes as containing recommended procedures and information of interest to pilots, adds operational guidance about which products satisfy that standard for different phases of flight.

One point that DPEs probe frequently: the TAF's 1-2-3 applicability. The 1-2-3 rule (covered in detail below) compares forecast conditions to thresholds — not observed conditions. A METAR showing 3,500 feet overcast at your ETA does not matter; what matters is whether the TAF forecasts at least 2,000 feet above airport elevation and 3 sm visibility.

How do you select an IFR route?

IFR route selection balances ATC preferences, terrain and airspace constraints, and aircraft capability. The first step is checking the FAA's preferred IFR routes for your city pair. Preferred routes are published in the Airport/Facility Directory (A/FD) and are designed to reduce coordination workload on heavily trafficked segments. Filing the preferred route increases the probability of receiving it as issued rather than an ATC reroute on the ground or in the air.

When no preferred route applies, the general hierarchy is:

• Victor airways (V-routes) — Low-altitude airways from 1,200 feet AGL to but not including FL180, defined by VOR radials. Each has a published MEA and MOCA. Suitable for aircraft without RNAV capability and for routes through complex Class B and C airspace where airways simplify clearance planning.
• Jet routes (J-routes) — High-altitude airways from FL180 to FL450, also VOR-based. Used in Class A airspace where RVSM requirements apply above FL290.
• RNAV T-routes — Low-altitude RNAV routes requiring GPS with appropriate avionics (RNAV 1 or better). Often more direct than victor airways in areas with sparse VOR coverage. Published MEAs apply.
• RNAV Q-routes — High-altitude RNAV routes at or above FL180, requiring GPS.
• Direct / random RNAV — Point-to-point routing filed as waypoints or lat/long coordinates. Common in Class A airspace. ATC approval is implicit when a clearance is issued; the ATCSCC may assign preferred routing to manage traffic flow.

The FAA's Air Traffic Control System Command Center (ATCSCC) issues traffic management initiatives (TMIs) — ground delay programs, miles-in-trail restrictions, and reroutes — when demand exceeds capacity. Checking ATCSCC advisories before filing helps you anticipate reroutes and brief your passengers accordingly.

How do you choose an alternate airport?

Alternate airport selection is governed by 14 CFR 91.169. The analysis has two distinct questions: (1) is an alternate required at all, and (2) if so, does the candidate airport meet the weather minimums?

If any condition fails — no published approach, ceiling below 2,000 feet AGL, or visibility below 3 sm — you must file an alternate. Note that the threshold is ceiling above airport elevation, not MSL. An airport at 5,000 feet MSL with a 2,200-foot ceiling is 2,200 feet above the ground but may have an MSL ceiling of 7,200 feet — always think in AGL for this calculation.

Once you've determined an alternate is required, the candidate alternate must itself meet the weather minimums in 14 CFR 91.169(c):

1. 1
   Precision approach at the alternate (ILS, LPV, GLS): Forecast ceiling at least 600 feet and visibility at least 2 statute miles at your ETA at the alternate.
2. 2
   Nonprecision approach at the alternate (LNAV, VOR, NDB, LOC): Forecast ceiling at least 800 feet and visibility at least 2 statute miles at your ETA at the alternate.
3. 3
   No published instrument approach at the alternate: Forecast weather must permit descent from the MEA, approach, and landing under basic VFR conditions.
4. 4
   Helicopter alternate planning: Forecast ceiling at least 200 feet above the approach minimums, and visibility at least 1 statute mile (or the approach visibility minimum, whichever is greater).
5. 5
   Verify the alternate has a published IAP you can fly: An airport with an ILS you cannot legally fly (e.g., no ILS currency) does not meet alternate requirements from a practical standpoint — the DPE will probe this.

One edge case DPEs use to trip up candidates: an airport listed as NA (not authorized) for alternate use in its IAP notes cannot be used as a filing alternate regardless of forecast weather. Always check the approach plate notes for "Alternate Minimums NA" or published non-standard alternate minimums in the front of the Terminal Procedures Publication (TPP).

What are the IFR fuel requirements?

14 CFR 91.167(a) sets three sequential fuel requirements for non-helicopter IFR operations:

1. 1
   Fuel to fly to the first airport of intended landing (your filed destination).
2. 2
   Fuel to fly from the destination to the alternate airport (if an alternate is required under 91.169).
3. 3
   Fuel to fly for 45 minutes at normal cruising speed after completing the alternate leg.

If no alternate is required (the 1-2-3 rule is satisfied), the requirement collapses to: fuel to destination plus 45 minutes at normal cruising speed.

The following table illustrates how to calculate fuel requirements for two planning scenarios using a hypothetical aircraft that burns 10 gallons per hour at 120 knots true airspeed:

These are minimum legal quantities. Prudent IFR planning adds a personal fuel reserve beyond the regulatory minimum — instrument approaches, holding, ATC reroutes, and weather deviations all consume fuel that the regulatory calculation does not account for. DPEs will ask how much fuel you actually planned to carry above the 91.167 minimum and why.

How do you file an IFR flight plan?

Under 14 CFR 91.173, no person may operate in controlled airspace under IFR without both a filed IFR flight plan and an ATC clearance. Filing is done via 1800wxbrief.com (Leidos Flight Service), a compatible EFB application, or by phone with a Flight Service Station.

The ICAO flight plan format (the standard for IFR filings in the U.S.) requires these key fields:

1. 1
   Aircraft identification (Field 7): Your N-number or, for military, the tail number. This becomes your ATC call sign.
2. 2
   Flight rules and type (Field 8): "I" for IFR. Aircraft type is the ICAO designator (e.g., C172, PA28, BE36) — not the common name.
3. 3
   Departure aerodrome and time (Field 13): ICAO airport identifier and proposed departure time in Zulu (UTC). Use ICAO identifiers (K prefix for U.S. airports: KBOS, KORD, KLAX).
4. 4
   Cruising speed and level (Field 15, route field header): True airspeed (N for knots, M for Mach) and requested altitude (A for hundreds of feet MSL, F for flight level).
5. 5
   Route (Field 15): Your planned route expressed as airways, fixes, direct segments, or a combination. Include the SID if you plan to accept one.
6. 6
   Destination, total estimated elapsed time, and alternate (Field 16): Destination ICAO identifier, EET in HHMM format, and the alternate identifier (if required).
7. 7
   Other information (Field 18): Special equipment, PBN capability codes (e.g., PBN/B2 for RNAV 5 with GPS), and remarks. This field drives ATC's understanding of what approaches and routes you can accept.
8. 8
   Emergency and supplemental information (Field 19): Fuel endurance (in hours and minutes), persons on board, emergency equipment, and PIC name and contact.

File your IFR flight plan at least 30 minutes before your proposed departure time to allow system processing. If you file through a flight service station by phone, the briefer will also provide a standard weather briefing — use this to confirm your weather analysis or identify anything you missed.

How do you brief the departure?

The departure briefing covers the instrument departure procedure (DP), the expected initial routing in your clearance, and lost-communications procedures. DPs come in two types: Obstacle Departure Procedures (ODPs) and Standard Instrument Departures (SIDs).

An ODP is a published procedure that provides obstacle clearance when no SID exists or when radar vectors are not available. You are not required to fly an ODP unless ATC assigns it or the procedure notes state it is mandatory. An ODP ensures at least 48 feet per nautical mile of climb gradient above obstacles; if your aircraft cannot meet a published non-standard climb gradient, you must use an alternative departure or obtain approval.

A SID is an ATC-assigned departure procedure designed to simplify clearance delivery and reduce frequency congestion. If ATC assigns a SID, you are expected to have the procedure loaded and understood before taxi. Key items to brief on any DP:

• Runway-specific departure routing — some SIDs have runway-specific transitions
• Published climb gradient — confirm your aircraft can meet it at maximum weight and density altitude
• Top altitude on the DP versus your filed cruise altitude
• Transponder, frequency, and contact instructions
• Lost-communications procedure for the initial departure phase (usually coded in the DP notes)

If no instrument departure procedure is published for your runway, the default lost-comm departure is: climb on runway heading to a safe altitude, then proceed on course. Brief this with your co-pilot or review it mentally before engine start.

How do you plan the enroute portion?

Enroute IFR planning centers on altitude compliance and contingency awareness. The governing regulation is 14 CFR 91.177, which establishes minimum altitudes for IFR flight.

When flying a published airway or route, you must comply with the Minimum Enroute Altitude (MEA) published for that segment. The MEA guarantees both obstacle clearance (1,000 feet in non-mountainous areas, 2,000 feet in mountainous areas) and VOR signal reception along the airway. The Minimum Obstruction Clearance Altitude (MOCA) provides obstacle clearance but only guarantees VOR reception within 22 nm of the VOR.

When no MEA or MOCA is published — for example, on a direct segment not aligned with an airway — 14 CFR 91.177(b) requires:

• 1,000 feet above the highest obstacle within a horizontal distance of 4 nautical miles of the course centerline, in non-mountainous areas
• 2,000 feet above the highest obstacle within 4 nm in designated mountainous areas

The Off-Route Obstruction Clearance Altitude (OROCA) printed on enroute charts provides a reference value for off-airway obstacle clearance, but it does not guarantee navigation signal reception. Use the OROCA as a cross-check — it does not replace the pilot's own altitude calculation for non-airway segments.

Additional enroute planning items:

• Minimum Crossing Altitudes (MCAs) — required altitude to cross a fix; you must initiate climb to meet the MCA before the fix, not at it
• Minimum Reception Altitude (MRA) — lowest altitude at which a fix can be positively identified using conventional navigation equipment
• Maximum Authorized Altitude (MAA) — ceiling for a jet route or airway segment; operating above the MAA will put you outside protected airspace for that route
• Hemispherical cruising altitude rules (14 CFR 91.179) — odd thousands eastbound (0–179°), even thousands westbound (180–359°), each plus 500 feet below FL290

Contingency planning is equally important. Identify divert airports every 50 to 75 nm along your route with published approaches you can legally fly. Know the weather at each and ensure your fuel calculation supports a divert without violating 91.167.

How do you prepare for arrival and approach?

Arrival preparation should begin 30 to 50 nm before the destination. If a Standard Terminal Arrival Route (STAR) is published and ATC has assigned it, load it before entering its transition fix. Brief the STAR the same way you brief an approach: expected routing, altitude restrictions, speed restrictions, and the transition from STAR to approach.

Approach selection follows this priority order for a non-precision-approach-equipped aircraft:

• Precision approach (ILS, LPV with appropriate avionics) — lowest minimums, most accurate guidance
• Approach with vertical guidance (LNAV/VNAV, LPV) — lower minimums than LNAV-only
• Non-precision approach (LNAV, VOR, NDB, LOC) — higher minimums, no vertical guidance; constant-angle descent path recommended
• Circling approach — used when the final approach course is not aligned within 30° of the landing runway; higher minimums apply

For the selected approach, brief the complete procedure:

1. 1
   IAF, IF, FAF, MAP, and missed approach point — understand the full procedure, not just the final segment
2. 2
   Decision Altitude (DA) or Minimum Descent Altitude (MDA) for the appropriate aircraft category (A, B, C, D)
3. 3
   Visibility requirement — confirm your aircraft category and the correct column in the approach minimums table
4. 4
   Missed approach procedure — brief it completely; DPEs expect you to execute the missed approach proficiently, not just recite it
5. 5
   Alternate missed approach — if the published missed approach is not available (e.g., NAVAID out of service), know the contingency

Check NOTAMs for the destination approach aids, runway lighting, and any approach component status before departure and again before the approach. An ILS glide slope NOTAM that grounds the precision approach may change your fuel and alternate planning.

What if conditions change in flight?

Conditions change. A PIREP reports severe icing on your route. The destination TAF drops below approach minimums. ATC issues a ground stop at your destination. The IFR pilot's decision framework for en route condition changes has 3 layers:

• Can you continue legally? If conditions ahead put you below IFR minimums with no alternate reachable on remaining fuel, continuing is not legal under 14 CFR 91.167 and 91.177.
• Can you continue safely? Legality and safety are different thresholds. An aircraft without deicing equipment has no business in known icing regardless of whether an AIRMET Zulu has been issued. Make your go/no-go based on your equipment, training, and currency.
• What is your best available divert? Use your pre-planned divert airports, current weather, and remaining fuel to select a divert point that leaves legal fuel reserves at arrival.

Declare an emergency when the situation requires it. 14 CFR 91.3(b) authorizes the PIC to deviate from any rule to the extent necessary to meet an emergency. ATC will assist. The FAA does not penalize pilots for declaring emergencies in good faith.

Communicate early. Informing ATC of deteriorating conditions, requesting a weather deviation, or asking for a divert before you are in extremis gives ATC time to build a solution. The worst decision-making happens when pilots wait until fuel is critical or they are already IMC in deteriorating conditions before asking for help.

How does MockDPE help with IFR cross-country planning scenarios?

The MockDPE AI examiner generates full cross-country planning scenarios drawn from real airport data, current-format weather products, and ACS task elements. You can practice the complete oral sequence — from weather briefing to alternate selection to fuel calculation to approach briefing — under realistic DPE pressure before your actual checkride.