Guest blocked pitot Posted September 28, 2003 Share Posted September 28, 2003 Please tell me I have not been doing this wrong the whole time! When it comes to a TEMPO in a TAF, when using an airport as an alternate, Can you use said airport if during the period of the TEMPO the weather is above alternate minimums? Lets say you need an 800 foot ceiling, the TAF says :" OVC 007 VIS 4 Tempo between 1218 BKN 015." I know it may not be wise to do so but is it legal? The only thing I can find is RAC 3.14 © The forecast TEMPO condition shall not be below the published alternate minimum requirements for that airport. Someone said there was more info in the CARS but I cannot find it. Link to comment Share on other sites More sharing options...
Guest BillyBigToe Posted September 28, 2003 Share Posted September 28, 2003 I believe both the main time frame as well as the TEMPO time frame must meet the alternate requirement. In your example, the forecast is calling for primarily below your minimum weather conditions, temporarily the weather will be above your requirement. No can use... Link to comment Share on other sites More sharing options...
Guest acm Posted September 29, 2003 Share Posted September 29, 2003 You're quote from the CARS says it all. So long as the TEMPO portion is above alternate minima, you may use it legally, even if the main part of the forecast is below minima. Link to comment Share on other sites More sharing options...
Guest Gasper Posted September 29, 2003 Share Posted September 29, 2003 (RAC 3-10) Aerodrome Forecasts (TAF’s) that contain the terms BECMG, TEMPO or PROB may be used to determine the weather suitability of an aerodrome as an alternate provided that: · where conditions are forecast to improve, the forecast BECMG condition shall be considered to be applicable as of the end of the BECMG time period and these conditions shall not be below the published alternate minima requirements for that aerodrome; and · where conditions are forecast to deteriorate, the forecast BECMG condition shall be considered to be applicable as of the start of the BECMG time period, and these conditions shall not be below the published alternate minima requirements for that aerodrome · the forecast TEMPO condition shall not be below the published alternate minima requirements for that aerodrome; and · the forecast PROB condition shall not be below the appropriate landing minima for that aerodrome. Link to comment Share on other sites More sharing options...
inchman Posted September 29, 2003 Share Posted September 29, 2003 I don't think so! You might want to look into that a bit further. Link to comment Share on other sites More sharing options...
Guest blocked pitot Posted September 29, 2003 Share Posted September 29, 2003 That's what I thought. People are telling me otherwise but cannot produce a reference to back it up. I may have to call TC. Link to comment Share on other sites More sharing options...
inchman Posted September 29, 2003 Share Posted September 29, 2003 ... available weather information indicates that the ceiling and ground visibility at the alternate aerodrome will, at the expected time of arrival, be at or above the alternate airport weather minima criteria specified... If the forecast is 800-2 TEMPO 500-1, can it be used as an alternate? No. Because TEMPO cannot be below alternate limits, even though it may only apply for a short period of time. But neither can the main portion of the forecast. So the reverse would not qualify, given that the general weather during the period is below alternate minima and weather is above minima only temporarily. One could say that the main portion of the weather is, by default a TEMPO condition, too, because it will not be that way througout the entire period, but that also underlines that it must be above minima. I guess the only thing that could be clearer would be to add the prefix WILLBE. Link to comment Share on other sites More sharing options...
GTFA Posted September 29, 2003 Share Posted September 29, 2003 How about just applying a little common sense to the issue? Would you really want to bet your life and your veeeerrrryyy little bit of remaining fuel on a temporary condition that may or may not exist at the time you would be arriving to shoot a last ditch approach? Sincerely, GTFA Link to comment Share on other sites More sharing options...
Guest blocked pitot Posted September 29, 2003 Share Posted September 29, 2003 PREVIOUSLY POSTED: "I know it may not be wise to do so but is it legal?" I just want to know if it is legal. Link to comment Share on other sites More sharing options...
inchman Posted September 29, 2003 Share Posted September 29, 2003 I agree wholeheartedly in marginal destination conditions: if you have to pick an alternate based on it being slightly on the side of legality and your destination is in the can, maybe an enroute landing for fuel is called for. On the other hand, there are times when, we carry an alternate with quite good weather at destination (and lots of runways to land on) so there is no way we are going to the alternate. Often in this situation, the alternate forecast can be significantly worse than the destination forecast... even very close to alternate minima. So, there is a place for the discussion in the real world ... I just don't think that a TEMPO condition above minima makes the rest of the forecast period legal. Link to comment Share on other sites More sharing options...
IFG Posted September 29, 2003 Share Posted September 29, 2003 Agreed, Inchman - Re: "I just don't think that a TEMPO condition above minima makes the rest of the forecast period legal." - The reference from the AIP quoted above does not state that an aerodrome is a valid alternate if the TEMPO is above limits, but only that the forcast "...may be used to determine the weather suitability of an aerodrome as an alternate provided that...". Obviously, if the main body of the forcast at ETA is below limits, you have already made that determination without reference to any BCMG's, TEMPO's or PROB's. If that seems like jailhouse lawyering, what else is new for pilots interpreting not just the CAR's (which of course contain no guidance on TEMPO's etc at all), but also the many and various Transport Canada interpretations, advisories, circulars, "so-and-so at Transport told me...", etc etc. In most cases tho', interpretations completely devoid of common sense will not stand up to a careful examination of the published reg's and guidance, even if the wording or syntax often leave much to be desired. Still, I do have a problem with forcast PROB's at minimums which, altho' legal, simply render the alternate marginless for 30-40% of arrival times within the forcast period. Unless the destination airport pretty much meets the standard for no-alternate IFR, I won't accept them. It don't take that many IFR sectors under the belt belt to know that weather can be worse than forcast, at both destination and alternate.:S Cheers, IFG Link to comment Share on other sites More sharing options...
IFG Posted September 29, 2003 Share Posted September 29, 2003 Agreed, Inchman - Re: "I just don't think that a TEMPO condition above minima makes the rest of the forecast period legal." - The reference from the AIP quoted above does not state that an aerodrome is a valid alternate if the TEMPO is above limits, but only that the forcast "...may be used to determine the weather suitability of an aerodrome as an alternate provided that...". Obviously, if the main body of the forcast at ETA is below limits, you have already made that determination without reference to any BCMG's, TEMPO's or PROB's. If that seems like jailhouse lawyering, what else is new for pilots interpreting not just the CAR's (which of course contain no guidance on TEMPO's etc at all), but also the many and various Transport Canada interpretations, advisories, circulars, "so-and-so at Transport told me...", etc etc. I'd hope that in most cases, interpretations completely devoid of common sense will not stand up to a careful examination of the published reg's and guidance, even if the wording or syntax often leave much to be desired. Aside from TEMPO's, anybody else have a problem with forcast PROB's at minimums which, altho' legal, simply render the alternate marginless for 30-40% of arrival times within the forcast period. Unless the destination airport pretty much meets the standard for no-alternate IFR, I won't accept them. It don't take that many IFR sectors under the belt belt to know that weather can be worse than forcast, at both destination and alternate. Cheers, IFG Link to comment Share on other sites More sharing options...
GTFA Posted September 29, 2003 Share Posted September 29, 2003 Now there's a question you'll never get a definitive answer to. You may get charged with some kind of crime at first, but then a clever lawyer will find some way get you cleared. Or you may not, but then some dark a dirty day you'll get fired for making a decision that your boss is unhappy with. Is that legal??? GTFA Link to comment Share on other sites More sharing options...
Guest flyguy93 Posted September 29, 2003 Share Posted September 29, 2003 Puzzling as it may sound, Weather forecast, are exactly that, just forecast, mere calculated predictions of what to expect. So you have a TAF valid for a set time frame, within that time frame there is a short period of different weather expected. 2 scenarios: 1. The whole time frame, the Weather is good however for the time period you are expected at your alternate airport, the weather is below alternate landing minimums, hence not a good alternate. 2. The whole time frame, the weather is terrible............. STOP right there!.. no need to read further as the TEMPO is a short time that TEMPORARILY changes weather of the original forecast.. Anybody?? Link to comment Share on other sites More sharing options...
GTFA Posted September 30, 2003 Share Posted September 30, 2003 Yah but... The original question was what's legal. Can you use the station as an alternate if the TEMPO shows above minimum requirements at your ETA??? GTFA Link to comment Share on other sites More sharing options...
Guest flyguy93 Posted September 30, 2003 Share Posted September 30, 2003 NO! Link to comment Share on other sites More sharing options...
GTFA Posted September 30, 2003 Share Posted September 30, 2003 Are you satisfied with that "Blocked pitot"? Link to comment Share on other sites More sharing options...
Guest blocked pitot Posted September 30, 2003 Share Posted September 30, 2003 No I am not. I have just emailed TC. Link to comment Share on other sites More sharing options...
GTFA Posted September 30, 2003 Share Posted September 30, 2003 I am willing to bet that you won't be satisfied with their answer either. Cheers, GTFA Link to comment Share on other sites More sharing options...
IFG Posted October 1, 2003 Share Posted October 1, 2003 Re: "I am willing to bet that you won't be satisfied with their answer either." - I'll be surprised if TC responds with anything more than a regurgitation of the reg's, and the guidance published in the AIP. While some inspectors freely offer verbal opinions and interpretations, I've found Transport to be wary of putting anything on paper beyond what's already printed in black and white. The reasoning that questions common sense answers to this (and blunt ones like flyguy93's) puzzles me no end. For instance, it would assert that (using a precision approach airport) - 6 OVC 2 BR TEMPO 3 OBSC 1 SN - not legal according to anybody here (phew ). But - 3 OBSC 1 SN TEMPO 6 OVC 2 BR - apparently legal according to some interpretations here (that TEMPO modifications supercede the main part of the forcast for the period) but still professionally unacceptable hopefully, because by the same reasoning, 3 OVC 1 BR PROB 40 2 OBSC 1/2 SN - also apparently legal? The main forecast is below alternate limits, the PROB deteriorates it even further but hey! PROB down to landing minima receives the same consideration in the AIP guidance as does TEMPO to alternate minima. Why twist one's self into believing that the reg's support nonsensical interpretations? :S More troubling, the question that started this seemed to seek reassurance that common sense prevailed in the requirements, now it looks more like they're determined to find otherwise.:| Cheers, IFG Link to comment Share on other sites More sharing options...
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