I cannot stress enough the importance of understanding and complying with mandatory reports under IFR.
These reports are crucial for maintaining safety in the skies and ensuring efficient traffic flow. To help you remember these reports, we use the acronym MARVELOUS VFR C500.
Each letter in this acronym represents a different mandatory report that you must make to ATC or FSS facilities without a specific ATC request.
Failing to report any of these situations can result in serious consequences, including loss of your pilot’s license or even a collision with another aircraft.
In this article, we will dive into each of these mandatory reports and discuss their importance. By the end of this article, you will have a solid understanding of MARVELOUS VFR C500 and the critical role it plays in aviation safety.
What is MARVELOUS VFR C500?
MARVELOUS VFR C500 is a memory aid used by pilots to remember the types of reports they need to make to ATC or FSS.
- Missed approach
- Airspeed changes more than 10 knots or 5 percent
- Reaching a holding fix
- VFR-on-top altitude change
- ETA change more than 3 minutes (no radar)
- Leaving a holding fix
- Outer marker inbound (no radar)
- Unforecast weather
- Safety of flight issues
- Vacating an altitude
- Final approach fix inbound (no radar)
- Radio or nav failures
- Compulsory reporting points (no radar)
- 500 FPM climb or descent unable.
Pilots are required to report any of these events to ATC or FSS to ensure the safety of the flight and other aircraft in the vicinity.
Why Do We Report These?
§ 91.183 IFR communications

According to § 91.183 of the Federal Aviation Regulations, pilots operating under IFR in controlled airspace are required to maintain a continuous watch on the appropriate frequency and report certain information as soon as possible.
This information includes the time and altitude of passing each designated reporting point or reporting points specified by ATC.
While under radar control, only the passing of specific reporting points requested by ATC need to be reported.
In addition to reporting passing points, pilots must also report any unforecast weather conditions encountered and any other information related to the safety of flight.
This requirement ensures that ATC has essential information to provide appropriate assistance and guidance to the pilot, helping to ensure the safety of the flight and other aircraft in the vicinity.
Pilots should be familiar with these reporting requirements and maintain effective communication with ATC to promote safe and efficient flight operations.
Failure to comply with these communication requirements can result in enforcement action by the FAA.
§ 91.187 Operation under IFR in controlled airspace: Malfunction reports

According to § 91.187, pilots operating aircraft in controlled airspace under IFR must report any malfunctions of navigational, approach, or communication equipment occurring in flight as soon as practical to ATC.
The report must include the aircraft identification, equipment affected, degree to which the capability of the pilot to operate under IFR in the ATC system is impaired, and nature and extent of assistance desired from ATC.
It is important to report equipment malfunctions as soon as possible to ATC in order to ensure the safety of flight and the efficient management of air traffic. Failure to report malfunctions may result in hazardous situations and unnecessary delays.
Each Letter Explained

Missed Approach
Explanation: A missed approach is a standard procedure that a pilot must follow if they are unable to safely land the aircraft during an approach. This can occur due to poor visibility, unsafe conditions, or other reasons that make it necessary to abandon the landing attempt.
Reporting requirement: Pilots are required to inform ATC or FSS immediately if a missed approach is necessary. They must also follow any specific instructions provided by ATC or FSS regarding the missed approach procedure.
Importance of reporting: Reporting a missed approach is important as it ensures the safety of all aircraft operating in the vicinity. It allows ATC or FSS to provide appropriate assistance and guidance to the pilot to safely execute the missed approach and to ensure that other aircraft are kept informed and appropriately spaced.
Airspeed Changes
Explanation: This refers to a change in airspeed of more than 10 knots or 5 percent.
Reporting requirement: Pilots are required to report to ATC or FSS any airspeed changes that exceed 10 knots or 5 percent of the previously maintained airspeed.
Importance of reporting: Reporting airspeed changes is important as it allows ATC or FSS to monitor and manage the flow of traffic in the airspace, ensuring the safety of all aircraft operating in the area. It also helps ATC or FSS to provide appropriate guidance and assistance to the pilot.
Reaching a Holding Fix
Definition: A holding fix is a designated location along an instrument approach where pilots may need to hold before proceeding to the next segment of the approach.
Reporting requirement: Pilots are required to report to ATC or FSS when they reach a holding fix.
Importance of reporting: Reporting reaching a holding fix allows ATC or FSS to monitor the flow of traffic in the airspace, ensuring the safety of all aircraft operating in the area. It also helps ATC or FSS to provide appropriate guidance and assistance to the pilot.
VFR-on-Top Altitude Change
Explanation: This refers to a change in altitude made by a VFR-on-Top aircraft while operating in controlled airspace.
Reporting requirement: Pilots are required to report to ATC any changes in altitude while operating VFR-on-Top.
Importance of reporting: Reporting VFR-on-Top altitude changes allows ATC to maintain separation between aircraft and manage traffic flow in the airspace, ensuring the safety of all aircraft operating in the area. It also helps ATC to provide appropriate guidance and assistance to the pilot.
ETA Change
Explanation: This refers to a change in estimated time of arrival that exceeds 3 minutes, when no radar is available.
Reporting requirement: Pilots are required to report to ATC or FSS any ETA changes that exceed 3 minutes.
Importance of reporting: Reporting ETA changes is important as it allows ATC or FSS to monitor and manage the flow of traffic in the airspace, ensuring the safety of all aircraft operating in the area. It also helps ATC or FSS to provide appropriate guidance and assistance to the pilot.
Leaving a Holding Fix
Definition: Leaving a holding fix refers to departing from a designated holding location along an instrument approach.
Reporting requirement: Pilots are required to report to ATC or FSS when they leave a holding fix.
Importance of reporting: Reporting leaving a holding fix allows ATC or FSS to monitor the flow of traffic in the airspace, ensuring the safety of all aircraft operating in the area. It also helps ATC or FSS to provide appropriate guidance and assistance to the pilot.
Outer Marker Inbound
Definition: The outer marker is a navigational aid used during instrument approaches to indicate the aircraft’s position relative to the approach path.
Reporting requirement: Pilots are required to report to ATC or FSS when they pass the outer marker inbound, when no radar is available.
Importance of reporting: Reporting passing the outer marker inbound allows ATC or FSS to monitor the flow of traffic in the airspace, ensuring the safety of all aircraft operating in the area. It also helps ATC or FSS to provide appropriate guidance and assistance to the pilot.

Unforecast Weather
Explanation: This refers to weather conditions that were not included in the pre-flight weather briefing and were not expected to affect the flight.
Reporting requirement: Pilots are required to report any unforecast weather conditions to ATC or FSS.
Importance of reporting: Reporting unforecast weather conditions is important as it provides ATC or FSS with updated information about the current weather conditions. This information is crucial in ensuring the safety of the flight and other aircraft in the area. It also helps other pilots in the vicinity to make informed decisions about their own flights.
Safety of Flight Issues
Explanation: Safety of flight issues refer to any conditions or situations that may jeopardize the safety of the aircraft, passengers, crew, and other persons on the ground or in the air. These issues include but are not limited to mechanical malfunctions, in-flight emergencies, medical issues, security threats, and weather hazards.
Reporting requirement: Pilots are required to report any safety of flight issues to ATC or FSS as soon as possible. This includes any unusual or abnormal conditions that may affect the safe operation of the aircraft.
Importance of reporting: Reporting safety of flight issues is crucial in ensuring the safety of the flight and all persons involved. It allows ATC or FSS to provide appropriate assistance and guidance to the pilot, coordinate emergency services if needed, and take necessary steps to ensure the safety of other aircraft in the area. Failure to report safety of flight issues may result in severe consequences and compromise the safety of the flight and all persons involved.
Vacating an Altitude
Definition: This refers to leaving an assigned altitude.
Reporting requirement: Pilots are required to report to ATC or FSS when vacating an assigned altitude.
Importance of reporting: Reporting when vacating an assigned altitude is important as it allows ATC or FSS to maintain separation between aircraft and to manage air traffic more effectively. It also provides ATC or FSS with updated information about the aircraft’s position and altitude, which is essential for ensuring the safety of the flight.
Final Approach Fix Inbound
Definition: This refers to the point at which an aircraft intercepts the final approach course on an instrument approach.
Reporting requirement: Pilots are required to report to ATC or FSS when inbound on the final approach fix, if radar service is not being provided.
Importance of reporting: Reporting when inbound on the final approach fix is important as it allows ATC or FSS to maintain separation between aircraft and to provide appropriate guidance to the pilot during the approach phase of the flight. It also provides ATC or FSS with updated information about the aircraft’s position and altitude, which is essential for ensuring the safety of the flight.

Radio or Navigation Failures
Explanation: This refers to the failure of any essential radio or navigation equipment on board the aircraft.
Reporting requirement: Pilots are required to report to ATC or FSS any failure of essential radio or navigation equipment.
Importance of reporting: Reporting radio or navigation failures is important as it allows ATC or FSS to provide appropriate assistance and guidance to the pilot during the flight. It also helps ATC or FSS to manage air traffic more effectively and to maintain separation between aircraft, which is essential for ensuring the safety of the flight.
Compulsory Reporting Points
Explanation: This refers to the inability of an aircraft to climb or descend at a rate of 500 feet per minute.
Reporting requirement: Pilots are required to report to ATC or FSS if they are unable to maintain a 500 FPM climb or descent rate.
Importance of reporting: Reporting the inability to maintain a 500 FPM climb or descent rate is important as it provides ATC or FSS with essential information about the aircraft’s performance. This information is crucial in ensuring the safety of the flight and other aircraft in the vicinity. It also allows ATC or FSS to provide appropriate assistance and guidance to the pilot.
500 FPM Climb or Descent Unable
Explanation: This refers to the inability of an aircraft to climb or descend at a rate of 500 feet per minute.
Reporting requirement: Pilots are required to report to ATC or FSS if they are unable to maintain a 500 FPM climb or descent rate.
Importance of reporting: Reporting the inability to maintain a 500 FPM climb or descent rate is important as it provides ATC or FSS with essential information about the aircraft’s performance. This information is crucial in ensuring the safety of the flight and other aircraft in the vicinity. It also allows ATC or FSS to provide appropriate assistance and guidance to the pilot.
Frequently Asked Questions (FAQ)
What is IFR?
IFR stands for Instrument Flight Rules, which are a set of regulations and procedures that govern how aircraft operate in certain weather conditions or airspace where visual flight is not possible.
What is the difference between IFR and VFR?
VFR stands for Visual Flight Rules, which are regulations that govern the flight of aircraft when visual flight is possible. IFR is used when the weather is not suitable for VFR, and requires pilots to rely solely on their instruments to navigate and communicate with air traffic control.
What is a missed approach?
A missed approach is a procedure used by pilots when they are unable to land their aircraft during an approach to an airport. The pilot will execute a go-around and climb to a safe altitude to attempt another approach.
What is a holding fix?
A holding fix is a predetermined location in the airspace where an aircraft can hold in a pattern while waiting for clearance to proceed to their destination.
What is a compulsory reporting point?
A compulsory reporting point is a specific location along an instrument flight plan where pilots are required to report to air traffic control or flight service stations. This helps ensure the safety and efficiency of air traffic control.
Why is it important to report safety of flight issues and malfunctions to ATC?
Reporting safety of flight issues and malfunctions to ATC is crucial for ensuring the safety of all aircraft in the vicinity. It allows ATC to provide appropriate assistance and guidance to the pilot and take any necessary action to avoid potential hazards.
Conclusion
In conclusion, flying under IFR in controlled airspace requires pilots to follow specific rules and regulations to ensure the safety of their flights and the other aircraft in the airspace.
It is important for pilots to understand these regulations, including reporting requirements for various situations such as malfunctioning equipment, unforecast weather conditions, and missed approaches.
By maintaining open communication with air traffic control and following proper reporting procedures, pilots can help prevent potential safety hazards and ensure efficient air traffic management. Always remember, safety is the top priority in aviation.