Switching frequencies too quickly

[jdoggchief]

Hi,

I have a question about departure procedures at John Wayne airport, based on an interesting interaction I had with ATC a few days ago. You can hear the relevant radio calls in this recording (I'm N43138; not sure if all the background noise in my transmissions is due to low bandwidth or the fact that I had a fan running in my room): http://assets.pilotedge.net/recordings/ ... _17510.mp3

I called clearance delivery to request VFR advisories to Ontario, and the controller told me "Departure frequency is XXX.X." My understanding is that this phraseology indicates that you're supposed to switch to that frequency as soon as possible after departure. So, once I got off the ground and stabilized in climb, I switched from tower to departure, but before I had the chance to call up, I heard "Bonanza 138, radar contact, remain this frequency." So I switched back to tower and responded. I was then handed off to approach about 30 seconds later.

Now, because this is PilotEdge, I was able to hear the command to "remain this frequency" from tower even though I'd already tuned approach, but in the real world, I wouldn't have heard that command and would have called up approach on my own and left the tower controller hanging. I have two questions about this. First, what would have happened if this had occurred in the real world? Would approach not have known who I was because I hadn't been handed off yet from tower? And secondly, how am I supposed to know when to stay with tower after departing and when to switch to the provided departure frequency? I feel like there's either a difference in the phraseology that I'm missing, or something in the airport remarks that I didn't catch. Either that or the controller just made a simple mistake and gave me the SoCal Approach departure frequency instead of telling me to stay with tower after departure in the initial clearance.

Thanks,
Jesse

[Anthony Santanastaso]

Hi Jesse,

There was no mistake made by the controller. You should never switch frequencies without being told to so (e.g., "Contact Departure"). The reason why the controller issues you the departure frequency as an item in CRAFT is purely for planning purposes, so that you know which controller will be responsible for radar identifying you and connecting the departure phase and the en route phase of your flight out of the immediate terminal environment. Utilizing good CRM (cockpit resource management), you would place the departure frequency in the standby of your COMM radio so that when told to do so, you can immediately establish contact with the radar controller.

The aspect of CRM to which I am referring is referenced in AIM, 4-2-3, Compliance with Frequency Changes:

e. Compliance with Frequency Changes.

When instructed by ATC to change frequencies, select the new frequency as soon as possible unless instructed to make the change at a specific time, fix, or altitude. A delay in making the change could result in an untimely receipt of important information. If you are instructed to make the frequency change at a specific time, fix, or altitude, monitor the frequency you are on until reaching the specified time, fix, or altitudes unless instructed otherwise by ATC.

There is only one circumstance (under normal situations) in which you would switch frequencies on your own and that is when you are taxiing outbound and can switch from Ground to Tower upon holding short of the active runway. But, think of it this way: once you are with Tower, all other frequency changes must be issued by the controller and you must monitor the frequency until further advised. That means that even when you land and taxi off the runway, you still have to hold short and wait for further instruction from the Tower controller.

Some of your confusion might exist because of the somewhat unique circumstances at KSNA. At most other facilities, Tower will instruct you to change frequencies upon departure when either clear of conflict or established on an initial heading. The Departure Controller, as referenced in my first paragraph, would radar identify you and get you on your way. KSNA is what's called a full radar tower. Full radar towers may use all forms of radar control to include (but not limited to) application of vectors, speed control, radar identification, radar traffic advisories, ground use of ASDE-X equipment, and assignment of beacon codes. Local procedure at KSNA is for Tower to radar identify the secondary target of VFR departures and then hand-off to Departure clear of conflict. This is the reason why you may have been confused. The Tower controller needed you to remain on their frequency until your secondary and primary radar information was appropriately identified (e.g., the controller established via radar who you were and made sure the Mode C altitude information matched what you saw on your altimeter). The actual Departure frequency of the controller that would establish you on your course out of the KSNA terminal environment was the one that was issued in your clearance.

Not being familiar with KSNA, you may not have known this was the procedure; however, always revert back to rule Number 1: once you are with Tower, all other frequency changes must be issued by the controller and you must monitor the frequency until further advised.

To answer your other question about whether or not Approach would have known it was you, the answer is yes because of your unique beacon code; however, in order to verify legitimacy in lieu of a radar hand-off, the controller might ask you to IDENT (depending on how long the delay was in the time you were out of contact with Tower and not radar identified) and require you to say altitude in order to verify the Mode C readout.

Please keep in mind that my whole explanation is in regards to towered airport operations. At non-towered airports, the departure frequency that you are given in your clearance is indeed the controller with whom you establish contact after departure. Bottom line is that you will never go wrong if you follow Rule Number 1 listed above!

Hope this helps.

Anthony

[jdoggchief]

Hi Anthony,

Thanks, that's very helpful! I think the main source of my confusion was that I got confused between the procedures for departing IFR from an uncontrolled field and departing a Class C field (probably because I've never done either one in the real world). I'll keep the rule you mentioned in mind, which should prevent future confusion. I'm glad I made this mistake on PE and not in the real world!

[Keith Smith]

Very good. The key difference between the two cases you described is that when you're departing from a non-towered field, there is nobody around to tell you to change freqs, so that has to be done at your discretion once you're clear of the traffic pattern. At a towered field (and any other time you're talking to ATC), the frequency change will be issued by ATC.

[jdoggchief]

Thanks Keith.

Just to clarify, isn't there one more time when you may switch frequencies without being explicitly told to do so by ATC? That being the situation in which you're leaving the airspace of a class D field. I remember once I got into trouble with that. I was departing Schnectady County airport, a Class D field which underlies the Albany Class C. I expected Schnectady Tower to issue me a handoff as I approached the border where the class D airspace changed to class C, but they didn't. (At the time, I didn't know that handoffs are never given to aircraft that are squawking VFR.) Finally I asked tower if I should be switching to Albany approach now, and the controller replied "frequency changes are at pilot's discretion when leaving Delta airspace, remain clear of the Charlie until contact is established with approach." I don't think I've ever hurried more to contact a controller! Luckily, I got in touch with Albany shortly afterward, and nobody seemed to mind this mistake.

[Anthony Santanastaso]

Thanks Keith.

Just to clarify, isn't there one more time when you may switch frequencies without being explicitly told to do so by ATC? That being the situation in which you're leaving the airspace of a class D field. I remember once I got into trouble with that. I was departing Schnectady County airport, a Class D field which underlies the Albany Class C. I expected Schnectady Tower to issue me a handoff as I approached the border where the class D airspace changed to class C, but they didn't. (At the time, I didn't know that handoffs are never given to aircraft that are squawking VFR.) Finally I asked tower if I should be switching to Albany approach now, and the controller replied "frequency changes are at pilot's discretion when leaving Delta airspace, remain clear of the Charlie until contact is established with approach." I don't think I've ever hurried more to contact a controller! Luckily, I got in touch with Albany shortly afterward, and nobody seemed to mind this mistake.

Yes, you are correct.