Communication Failure under IFR — Page 127, Lesson 112

I want to walk you through the procedures for communication failure when you're flying under IFR — that's Instrument Flight Rules. This is a critical section because losing your radio while in controlled airspace, especially in cloud, demands a very precise, predictable response so that Air Traffic Control knows exactly what you're going to do. Let's start with the fundamental split. The initial actions for any communication failure — whether you're VFR or IFR — are the same: you check your equipment, you try transmitting blind, you do all the basic troubleshooting. But after that, the procedure diverges based on one key question: can you stay in Visual Meteorological Conditions, or VMC? That means you can keep clear of cloud during your descent and landing. Or, are you in Instrument Meteorological Conditions, IMC, meaning you cannot avoid flying in cloud? If you are on an IFR flight but you can maintain VMC, the procedure is identical to the VFR communication failure procedure. You must do three things: continue to fly in VMC, land at the nearest suitable aerodrome, and then report your arrival by the most expeditious means — that's the fastest way possible — to the appropriate Air Traffic Services Unit, or ATSU. Now, the more complex and critical case: IFR in IMC. If you are in cloud and you lose communications, the rules change completely. The ICAO standard gives you two different sets of timing, depending on whether radar is used for air traffic control in that airspace. First, in airspace where radar is not used for ATC. In that case, you must maintain the last assigned speed and level — or the minimum flight level if that is higher — for a period of 20 minutes. That 20-minute period starts following the aircraft's failure to report its position over a compulsory reporting point. After those 20 minutes, you then adjust your level in accordance with the filed flight plan. Second, in airspace where radar is used for ATC. Here, the holding period is shorter: 7 minutes. You maintain the last assigned speed and level, or the minimum flight altitude if higher, for 7 minutes. But the key detail is when that 7-minute period starts. It begins at the latest of three possible trigger times: the time the last assigned level or minimum flight altitude is reached; or the time the transponder is set to code 7600 — that's the squawk code for communication failure; or the time the aircraft fails to report its position over a compulsory reporting point. Whichever of those three events happens last is when your 7-minute clock starts. After that 7 minutes, you then adjust level and speed in accordance with the filed flight plan. There's another important case: if you were being radar vectored, or if ATC directed you to proceed offset using RNAV — that's Area Navigation — without a specified limit, you must proceed in the most direct manner possible to rejoin your current flight plan route. You need to do that no later than the next significant point, and you must take into consideration the applicable minimum flight altitude. Finally, once you've completed the holding period and adjusted as required, you proceed according to the current flight plan route to the appropriate designated navigation aid or fix that serves the destination aerodrome. And when required, you hold over that aid or fix until you commence your descent.