ATC says...

[Guest TheJones]

Here are some simple ATC instructions in different situations. What exactly are you cleared to and what will you do to comply correctly?1. You are at your cruise level(say FL350), 25nm out from TOD. ATC says "AAL327 descend maintain 19000".2. same situation, ATC instructs "AAL327 descend maintain 19000, good rate to 25000".3. You are 13nm inbound to standard straight-in ILS procedure. The published starts at 3000' - you were cleared to 5000' earlier, still on descent. Now ATC clears you as follows: "ACA3339 cleared for straightin ILS approach runway 12, report fully established".4. You are on ILS CAT3 approach, Low (or no) visibility. You suddenly lose the ILS signal. what will you do (with respect to different phases of approach and altitudes)?5. It is a busy day at the airport, atc clears you to land and requests you to vacate runway ASAP. High speed turns are available all over. 6. You are lined up, tower says "ACA856 cleared for takeoff 2500 feet initially, maintain runway heading, expect vectors for departure. contact departure on 120.5 when airborne, gday". You roll, takeoff but you don't manage to get in touch with departure. What are you expected to do?

[Guest GeorgeDorkofikis]

Ok...here goes:>1. You are at your cruise level(say FL350), 25nm out from TOD.>ATC says "AAL327 descend maintain 19000".ATC using wrong phraseology. It should say 'descend [and] maintain FL190'... If we put this aside, I would confirm and go to the DEScend page in the FMC and press the DES NOW option, provided I'm on VNAV.Otherwise I would start a slow descend of 1000ft/min until I meet my VNAV path.>2. same situation, ATC instructs "AAL327 descend maintain>19000, good rate to 25000".Wrong phraseology again, but will ignore that :-)Being 25nm from TOD, ATC may be foreseing a possible conflict with other traffic which would delay our descend or may result on possible TA/RA. In this case I would start a normal LVL/CHG descend until passing FL250 after which I would resume a shallow 1000Ft/Min descend until I intercept the VNAV Path.>3. You are 13nm inbound to standard straight-in ILS procedure.>The published starts at 3000' - you were cleared to 5000'>earlier, still on descent. Now ATC clears you as follows:>"ACA3339 cleared for straightin ILS approach runway 12, report>fully established".Since ATC cleared us for ILS approach and NOT to 'join the localizer', I would continue normal descend to 3000Ft (published IAF), level and capture the ILS. IF I am already BELOW the G/S and in good course, I would engage APP mode (if in autoflight), otherwise I would engage LOC and wait to reach 3000Ft and capture the localizer before engaging APP mode.>4. You are on ILS CAT3 approach, Low (or no) visibility. You>suddenly lose the ILS signal. what will you do (with respect>to different phases of approach and altitudes)?Although I am not certified for CATIII approaches :-LOL I would go around of course no matter where I am in the approach.>5. It is a busy day at the airport, atc clears you to land and>requests you to vacate runway ASAP. High speed turns are>available all over. Autobrake at 1, max reverse until speed around 60kts, then idle reverse and normal idle to a suitable high speed exit.>6. You are lined up, tower says "ACA856 cleared for takeoff>2500 feet initially, maintain runway heading, expect vectors>for departure. contact departure on 120.5 when airborne,>gday". You roll, takeoff but you don't manage to get in touch>with departure. What are you expected to do?Hmmm... tricky one... If clearance had given me an SID on the initial clearance I would follow the cleared SID up to the cleared initial altitude or as is published for the given SID. Continuing to try to contact departure. If still unable after a normal period of time I would try to contact either the approach controller or the control.Nice quiz!George DorkofikisAthens, Greece

[Guest TheJones]

>ATC using wrong phraseology. It should say 'descend [and]>maintain FL190'... Not if TL is above FL190, or when other rules are published. for example in Israel when flying overland you are never using QNE - only local qnh are used and airplanes fly altitude not flight levels.No mistake here ;-)I'll wait for some more answers before giving my answers - thanks George!

[Guest GeorgeDorkofikis]

Aha!...You learn something every day. That's something I did not know.Actually I never heard of TL above FL180.Thanks for the clarification :-)George DorkofikisAthens, Greece

[Guest]

1. VNAV DES page & line select DES NOW.2. Engage LVL/CHG until passing FL250 then resume VNAV for the remainder of the descent.3. Since we are cleared for the ILS approach I would descend to the published altitude in this case 3000'.4. Above DH/AH: Continue until satisfied that it is not a temporary signal loss taking into consideration the G/S OUT MDA. Once satisfied that it is not temporary signal loss then at this time we would execute a missed approach. Below DH/AH: Continue if satisfied that it is safe to do so.5. Full manual braking to provide maximum deceleration as well normal reverse.6. Continue with lost communications procedure applicable to the DP/SID while simultaneously contacting another station making them aware of the situation.Best Regards,

[Guest TheJones]

>6. Continue with lost communications procedure applicable to>the DP/SID while simultaneously contacting another station>making them aware of the situation.You are not on a published SID - you were requested to fly runway hdg and expect vectors from departure ATC... I know it's a nasty one ;-)

[Guest]

Ilan,Well in that case I would contact another station to make them aware of the situation. Upon recognition of the communications failure I would then set transponder to 7600. Proceed directly on couse and maintain the last assigned altitude in this case 2500' until 10 minutes after departure then climb to flight planned altitude.Best Regards,

[Guest ielchitz]

6. You are lined up, tower says "ACA856 cleared for takeoff 2500 feet initially, maintain runway heading, expect vectors for departure. contact departure on 120.5 when airborne, gday". You roll, takeoff but you don't manage to get in touch with departure. What are you expected to do?A lot of it has to do with my initial clearance, so I'll assume that part of it was "...expect FL330 one zero minutes after departure". (There is a reason they say that). Also, since I'm on "vectors" I'll make the assumption that I'm not on any type of DP/SID with NORDO procedures to follow.In this case I fly runway heading and maintain 2500 feet for 10 mins (unless not safe to do so) - then I climb to FL330 and continue on course.In reality I'd squawk NORDO and look for another controller to contact and tell them that XXXX isn't responsive - I might even go back to the tower guy and ask him to call the guy on 120.5 and wake him up.On Vatsim I'd just send a private message to the controller telling him to wake the heck up or disconnect .

[Guest Lenny Zaman]

1. enter a shallow 1000fpm descent and recapture VNAV path upon reaching, MCP ALT set to 19k2. LVL CHG down to 25k and then a shallow 1000fpm to recapture VNAV path upon reaching, MCP ALT set to 19k3.MCP ALT down to 3k, speed to 210IAS(initial approach speed, at least at EBBR that is, otherwise i check the IAP if any reference is made), proceed on IAP as published and report just after capturing both LOC and G/S4.if still on initial approach course(course to join localiser): advise ATC of loss, request immediate instructions, if localiser just came alive: continue turn to a heading wich provides a lineup with the runway track(so, rwy hdg = + or - x degrees for wind comp(=visible on EHSI))(via HDG SEL) and adivse ATC, req immediate instructions, if allready on the localiser but not on G/S, proceed on heading(HDG SEL) and maintain present altitude(MCP ALT HLD) contact ATC as soon as practisableif fully established above minimums(remeber only CAT3c has a RVR of 0m) proceed on Missed approach procedure and advise ATCif runway visible, proceed with normal landing, after landing notify ATC of the situation5. normally if you fly often you start to know landing distances quite good, set autobrake to appropriate setting to exit off the first available 'less than 90

[Guest ielchitz]

FL200 can also be the minimum if the altimeter is below 28.92.

[Guest TheJones]

Excellent guys, excellent :-)Some of my remarks:1. When requested to start your descent earlier than TOD, most ATC (me included) will kill you if you descend too slowly. IMHO pressing DES NOW will engage a VERY slow descent until regular descent path is intercepted. I would use FLCH for this cases.2. If an ATC requests "good rate" to alt XXX, better be there ASAP for your own safety - this must be the next "safe" altitude. I would actually use V/S to determine my rate of descent until 25000, then VNAV or FLCH as required. You'll need to monitor speed though, so you won't overspeed during descent.3. good answers here - you are actually cleared to 3000' -> thence go ILS. Lenny described it all right.4. That's a tough one - Ryan (Ryno) got it right: main question is whether you are above or below AH (some manuals state the checkpoint is always 200ft). You have to check if it is safe to continue the landing if below AH and do so if able.5. Yeah yeah, don't listen to us. But correct - first land the bird, then try and help ATC. many of the accidents/incidents I met happened when the pilot tried to help somone else... thus: Autobrake + reverse as needed, clear runway at the first available taxiway and tell atc that he must be blind, that was fast as hell (+ it was the plane behind you now on a missed approach flying too fast on final).6. Ok that was a nasty one. No SID is given, and you are actually on clearance limit point. Procedures requires you to start a holding pattern now - but would it be the safest thing to do?I brought this example to show that procedures must be met, but you need to use your common sense sometimes. starting a holding pattern inside a CTR or TMA area is a disaster. Ryan's' Lenny's and Ian's ways are also a good procedure, but it might not be good enough. Good point about MSA Lenny - it is the bible of a no-comm situation.I would say the following, based on my experience in aerodromes:most tower positions are non-radar. you don't want to penetrate a radar controlled area without radar ID. The best thing to do is to "pause". a pause in aviation is a holding. a holding inside a CTR is actually a circuit pattern. In my experience the best place to be in this situation is at downwind leg, or to be even more safe - 500' below regular circuit altitude (which will place you just between regular and light airplanes on circuit - just in case). Best of all - you can go there under ATC - just switch back and call tower, request the turn if ATC doesn't instruct you so immediately (and he should, unless he has radar).This is one of many possible solutions, all depends on traffic and other changing parameters. Most accidents/incidents occur inside CTR's - you don't want to travel around blind and uncontrolled in these areas. My 2.5 cents for now ;-)

[Guest HPSOV]

2. If an ATC requests "good rate" to alt XXX, better be there ASAP for your own safety - this must be the next "safe" altitude. I would actually use V/S to determine my rate of descent until 25000, then VNAV or FLCH as required. You'll need to monitor speed though, so you won't overspeed during descent.Why??Using V/S simply removes your speed protection without achieving anything. FL CH and VNAV will both give you the same rates of descent (as they will both give you idle thrust). There are only 2 ways to increase your rate of descent, one is speedbrake, the other is a higher speed. I wouldn't use speedbrake to correct for what is a fault by ATC unless they make a second request for me to increase the descent rate. In that example I would remain in VNAV and speed intervene to a higher speed (say .83/330 where profile would have been .80/300), the pitch mode will trip from VNAV PATH to VNAV SPD and we'll duck under the profile (provided you're in a pegasus aircraft, otherwise you must use FL CH). Once below FL250 cancel the speed intervene and the aircraft will decelerate to 300kts and end up very close to being on path again.

[Guest TheJones]

Speed intervene is also a good option. I accept everything else you said as well, except waiting for a second request by atc - you should do as your told regardless of the reason. a good rate must be a good rate (most people would give double v/s, that's a good rate from ATC POV).

[Guest HPSOV]

I'll have to say its not something I've ever come across really. I'm always wary of requests that are non-specific, if ATC has a traffic situation to organise then in my experience they will give you a hard requirement... "Cross XXX at or below FL250", that way there can be no doubt as to separation. As there is no deifinition of a 'good rate' I'd hope ATC would use it with caution, there could be a lot of different interpretations of a good rate!I think it could largely be regional differences in ATC, flying predominantly in Asia ATC give specific instructions, little is left to interpretation.Use of speedbrake will only give you about a 50% increase in V/S at altitude, reducing to 25% at 250kts, and 20% at Flaps5. Maintaining double normal v/s would only be possible in certain phases of descent.

[PeteP 2]

HPSOV,...to correct for what is a fault by ATC unless they make a second request for me to increase the descent rate.Whatever makes you think that an instruction to expedite (what I assume Illan means by "good rate") a descent - or climb for that matter - is the result of an "ATC fault"? The ability to vary an aircraft's vertical rate (even over a very limited range)is a perfectly valid controlling tool which is available to controllers in all situations - not just to correct errors! It needs to be used with extreme care but, properly used, it can often provide the solution to problems, especially in areas of high traffic density, that would otherwise require extensive vectoring or long 'stop-offs' to wait for a pass. What's really puzzling me, though, is the phrase "..unless they make a second request...". I may well have misunderstood what you mean here - I hope I have - but it seems to imply that you would accept a clearance and then do nothing about complying with it until told a second time. Pete