JIs it required or necessary to respond back to the controller with an altimeter setting??
The single, most important thought in pilot/controller communications is understanding. It is essential, therefore, that pilots acknowledge each radio communication with ATC by using the appropriate aircraft call sign.
I see that one controller here said he doesn't care, but other controllers have stated that they like to know if the pilot heard the transmission.
Still, the most important aspect of a readback is to ensure the accuracy of the information you received. This is important not only for your safety, but also to make sure you can adhere to ATC altitude assignments. You're giving up one level of safety by failing to readback the number.
Here's what Don Brown, formerly of Atlanta Center, says about it :
While we are here, have you ever stopped to analyze the structure of a check in? Obviously there is some information being passed, but have you ever thought about it being a "communications check"? Let me show you an example to explain what I mean.
I had a King Air check in yesterday like this:
"Atlanta Center, King Air one one Alpha Alpha with you at ten."
Ignoring the sloppy phraseology I replied:
"King Air one one Alpha Alpha, Atlanta Center roger, Hickory altimeter 3012."
There was no reply. I thought that was kind of curious. I also had the sneaking suspicion that he heard me. So I called him back:
"King Air 11AA, Atlanta Center, how do you read? "Loud and clear Atlanta, 11AA."
After browsing through the AIM I can't swear to you that he's required to answer me when I give him an altimeter. I know that I'm required to give him one. From the Controller's Manual:
And I could stretch it with a quote from the AIM:
4-2-3. Contact Procedures c. Subsequent Contacts and Responses to Callup from a Ground Facility.
You should acknowledge all callups or clearances unless the controller or FSS specialist advises otherwise.
Of course the AIM isn't regulatory anyway. But if he reads back the altimeter correctly, I know that we have established good communications. I also know that he has his altimeter set correctly.
I've seen a controller charged with an operational error because he didn't catch that a pilot read back an incorrect altimeter. When that aircraft passed another aircraft with only 600 feet of altitude separation, instead of the required 1,000 feet, the "snitch machine" (Operational Error Detection Program) went off. I've seen TCAS RAs (Resolution Advisories) caused by incorrect altimeter settings. I've also been chewed out by a pilot (rightly so) for issuing him an old altimeter. The altimeter was six hours old and I didn't notice. Fortunately the pilot did. The altimeter I gave him would have put him 300 feet low on an approach to an airport where the weather was 200 overcast.
Have I ever mentioned that everything
in this business is important?
My how time flies when you're having fun. Where were we? Oh yeah, following I-40. You ought to be approaching Hickory (HKY) by now. Your VFR cruising altitude of 4,500 puts you well above HKY's traffic pattern and Class D airspace, so you don't have to worry about that.
Right Height for Flight
I hope you've noticed that 4,500 is a correct altitude for your direction of flight (westbound). I can't overemphasize how important it is to fly at the correct altitude for direction of flight. "East odd, west even" is almost second-nature for controllers. That simple principle has separated more airplanes than air traffic controllers ever thought about separating. There are a lot of people (including controllers) who don't believe that. Trust me on this one. It's one of the best habits you can have as a pilot.
Something else I hope you've noticed. The interstate tends to go by a lot of airports. You've already passed SVH and HKY. The next one you'll be approaching is Morganton (MRN). While 4,500 has put you well above the traffic operating around HKY and SVH, the approach into MRN starts at 5,000. The NDB at MRN (FIQ) is right next to I-40. So if you hear the controller working someone shooting approaches into MRN you can expect to have some traffic.