Dec 2, 2020

Loss of radio communication?

We all know (more or less...) the procedure to be followed in case of 2-way comms failure.

Since most of our flying is done under radar contact/control, I think we can assume that the 7 minute rule usually would apply (unless under radar vectoring), so we would maintain ASSIGNED FL/speed for 7 minutes after 7600 is set (the other 2 being failure to report position over compulsory point and time last assigned FL/speed is reached, but I think that usually 7600 would be the last of these 3 to occur?), after this time we regain FILED FL/speed.

If under vectoring, from the way I have the wording in my books I would assume you proceed DIRECT to the next fix on your CURRENT FPL (rejoin in the most direct manner possible the current FPL), and then follow CURRENT FPL to the navaid/fix serving the destination until EAT/ETA, so as to land within ETA+30 if possible.

Now in theory this all seems feasible, but how would this actually play out outside of our books? Say we are flying BRU-AGP, and somewhere overhead Paris someone spills the coffee on the center pedestal, killing the radios. We try and contact next center, but get no reply and we don’t hear anybody either. Squawk 7600, timer top for 7 minutes. We were given direct to a fix, so we just keep going to the fix, after which we follow the route as we have it in the FMC? After this time, we climb/descend to our filed FL, and do we then just follow the filed route all the way to AGP?

Suppose we are ahead of schedule by 15 minutes, does that mean we have to enter the hold overhead/at the IAF until ETA, and only then we commence the descent?

Furthermore, what happens once on the ground? I assume they’ll have a follow-me waiting for us to take us to the gate? What if there isn’t? This is outside of the scope of the regulations, more operational, but still....

I think I understand what the regulations are, but I’m just finding it somewhat difficult to put it into real life... Also seems to be a topic that doesn’t get discussed very often (or at least not that I have heard).


Hi Jordy,

Thank you for your question! You will actually find the whole Lost Comms procedure flow chart in The 737 Handbook in chapter 18 - Miscellaneous. Just to quickly answer your questions:

  1. Yes you would follow your filed flight plan (routing and level)

  2. At designated NAV AID for given airport (that could be IAF or any other point stated in AIP) you would have to enter a hold at filed flight level and commence descent at ETA (according to Flight Plan) or if issued at EAT (normally not issued unless delays are expected).

  3. Once on final approach visual light signals as per ICAO standard should be used and I would expect a follow me to guide the aircraft to the stand

I hope that this answers your questions. For more have a look in the Handbook, you will also find there different state rules and regulations deviating from the general European lost comms procedure.

- Petr

Dec 12, 2020

Hi Petr

can you give us the lost comm (ICAO) procedure elaborately on 737 HANDBOOK Plz ...waiting for the update

Dec 3, 2020Edited: Dec 3, 2020

I know it would be highly impossible, but if diverting to ALTN, what FL to choose? ;) It would be definately a bad day.

Dec 12, 2020

Trust me Mr. Gizbels really grabbed a grt point....it’s my question too. And what if we have to divert to alternate ?