Mandatory Pilot Reports
While enroute, pilots are required to report the time and altitude of passing each designated reporting point when not in radar contact, any unforecast weather conditions encounters, and any other information relating to the safety of flight.
Designated reporting points include compulsory reporting points and those points at which air traffic control specifically requests a report. If along a direct route, the points used to identify your route are designated reporting points.
Making position reports not specifically requested by air traffic control is not necessary after you hear the phrase, "radar contact", but must be resumed after you hear, "radar contact lost".
While the minimum legal requirement for a position report is that the pilot report time and altitude of passing, it is customary for a pilot to also provide a time estimate for the next reporting point. For example, "Denver Center, Cessna seven zero four golf lima at Rawlins, 10,000 feet at 1308 zulu, estimating Hayden at 1344 zulu."
In addition to the mandatory reports, these reports should also be made to air traffic control without a specific request:
1. Vacating a previously assigned altitude.
2. When an altitude change will be made when VFR-on-top.
3. When unable to climb or descend at 500 feet per minute or greater.
4. When you go missed approach.
5. Whenever true airspeed varies by 5% or 10 knots, whichever is greater, from that filed in the flight plan.
6. The time and altitude or flight level upon reaching a holding fix or clearance limit.
7. Leaving a hold.
8. Loss or impairment of navigation capabilities, along with the nature and extent of ATC assistance desired.
If you are not in radar contact, the additional reports should be made to air traffic control without specific request:
1. Leaving the final approach fix or outer marker inbound on final approach
2. Revised estimate for your next reporting point if different from the previously submitted estimate by 3 minutes or more.
Pilots may also make reports of conditions such as icing and turbulence at their discretion. These reports aid weather forecasters and other pilots. In order to be useful, pilot reports must be made in a standard way by all pilots. Chapter 7 of the Aeronautical Information Manual contains guidelines for making pilot reports.