Holds Part 1

you hi and welcome to another ifr video this is the first in a series of videos about IFR holds in this episode we will learn about the dimensions of a holding pattern you probably already know that regulations specified that the unbound leg of a holding pattern must be one minute long when holding at or below 14,000 feet or one and a half minutes when holding above 14,000 because the regulations specify time and not distance for the unbound leg pilots have traditionally held by reference only to watches but with most modern airplanes equipped with GPS these days it is my purpose to show you that you can hold much more effectively and easily if you translate the requirements into distance let me show you what I mean there is a fixed relationship between velocity distance and time such the distance equals velocity times time to use this relationship the first thing we need to know is our speed in this video I'm going to fly a couple of demonstration holds in a light twin at 6,000 feet and 120 knots indicated air speed these are quite typical values for many IFR training aircraft we must realize that even though our indicated speed is 120 our true airspeed is higher let's break out the CX to to get an idea of what our true airspeed is entering 120 is the calibrated speed and 3.1 degrees Celsius as the standard temperature and 6000 as the pressure altitude we see that true airspeed is 131 knots for this first video we will examine dimensions for hold in zero wind I promise we will cover the effect of wind thoroughly in an upcoming episode so we know that ground speed will be 131 throughout the hold therefore the inbound leg must be 131 times one sixtieth of an hour run that through your calculator and round off to one decimal which is all the accuracy we need and we have 2.2 nautical miles now just knowing this one number is a great help since it gives us something to shoot for but to take full advantage of our GPS we need to know more as the airplane reaches the outbound leg of a hold the GPS tells us the cross track distance in zero wind hold this cross track distance will remain constant along the entire length of the outbound leg what should this value be grade 10 math gives us the answer the diameter of a circle is equal to its circumference divided by pi the two 180 degree turns of a holding pattern are of course just a circle interrupted and we know it takes one minute to fly each turn or two minutes to fly a complete 360 so the circumference of this interrupted circle is equal to our ground speed times two sixtieths of an hour in our case that's four point four miles in dividing that by pi we get one point four nautical miles once again I've rounded off to one decimal place we now have two useful numbers one more number will make flying the hold a piece of cake if we know the diagonal distance across the hold we will know exactly when to turn inbound without the need to refer to a stop watch great 10 math to the rescue again Pythagoras gives us the solution run these numbers through your calculator and you will come up with 2.6 nautical miles I guarantee you that if you turn inbound when your cross track reads 1.4 and your diagonal distance reads 2.6 you will roll out in the perfect position to get exactly a 1-minute inbound leg okay enough talk let's give it a try okay so we're tracking inbound to the Abbotsford beacon on a track of zero six seven degrees we've cleared the whole West as published so that Olga's an inbound track of zero six seven standard mold right turns it's just going to be a direct entry and there is ZERO wind so we'll find out whether mentions that we just worked out actually work or not it's right now I have the abbot's Randy Ken on the GPS I also have the abbot's freaking tuned and identified on I have my HSI set to a course of zero six seven I have the are my selector in GPS mode the green are my needle is pointing at the answer to begin through the GPS and the yella meal is always on AF so I have the two needles on my arm I'd biking at the African GPS says I'm seven miles from the beacon right now so I'll begin slowing down to it's indicated and once we're slowed down check our ground speed and see if it's higher if everyone knots as we now I've already switched the GPS to Oh gasps no because I come down to five miles from the six when your switch now so five miles from the station we are in Oh PS modes the drop down for about 127 right now when we reach we all we have to do is make a 100 at a rate 1/2 having a two for seven degrees so there are 200 21 knots almost there Ott's established about in half miles back I have the GPS setup doesn't show rounds page two of such nav page one so there we are ground speed 131 science is amazing Senora Church because once everyone's that confirms that the wind is indeed calm and pretty much right on track one when I heard so auf doesn't really can a mile a half-mile or almost there just wait for the to fajn flag to shut on my HSN there goes the our mind there goes the flags so I turned about yes decisis I can to not slows what this tad is speech on the powers if I can correct that so we're all on our reciprocal heading now we wait for the two throng flag to flip before we start our outbound time I am going to start the outbound time goes start my my stopwatch so taking the time to perfectly honest not even really going to look at it it's just the backup section my cross track and 1.37 as far as I'm concerned that rounds off to one point four so that seems perfectly good to me and I'm just going to hold this heading out until I get to a diagonal distance of 226 miles could should correspond to one minute but it's not the time go by it's the distance is theirs just coming up on 2.1 miles my crosstrack still steady there's 2.3 miles bug said before I get to 2.6 five 52.6 we roll into the turn and I'm sure you note it at the time was just about exactly one minute so we could have gone by that but it's more consistently reliable to go by the distance you'll also find that it's much easier from a work especially if you're busy as you attempted we are checklist all kinds of stuff that tends to distract you it's not easier to go by distance than it is things are looking pretty good here so as I get closer I already knew all that I like to get my finger ready on the button as I begin to all out and hit the button right above there and if you know this the distance to the station lies exactly two nautical model so I already know this is going to be exactly one minute we'll play it out just so that I can show you that it's a minute but in all honesty I already know it's going to be that's fast there that'll throw it off by a couple of seconds so I just fixed that there's just coming up to 50 seconds design my clocks is one minute right now and there's the flip it doesn't really get okay so that pretty much confirms that the dimensions of the holding pattern are exactly what we calculated and we'll do one more demonstration this time we'll set up for a monster on the board with left turns okay we're back and this time we're tracking to you I can do one deservedly radio and hold Southwest on the two three zero Degree radio at 6,000 feet non-standard lock turns this would be another once again winds are calm so I have the Whatcom you are set up as the accurate weight one time that you guess and I also have to watch our tune have one and it's also tuned to identify it on have to by HSI sand up to of course of 0 5 0 degrees yeah I have 0 5 0 also set my I have my Pharma selector on one so the green the atmosphere Buchan to my GPS shows me down to seven miles matches that or begins flowing down to 120 watts and you're supposed to zero wind I noticed that I'm having to halt two or three degrees of drift collection beers I think the simulator maybe has some phantom wind built-in that's okay I just throw things off here so coming down to five miles I'm already in we'll be so2 in this case but if I wasn't I would switch over to go yes no now five dots to go on here spoon we're just about there at 120 knots fine tune our oops the last you have miles to go so this time since it's a nine step upon reaching the make a left degrees I will be having rings to the left just check out our ground speed here still iron still shows zero well as far as that's concerned correct just a little bit get perfectly on track the GPS is in in this case because within 30 miles of my destination Airport mode doesn't really matter you notice I have the map scales up to ten miles spell or smaller scale I notice a lot of students like too soon see that as tickler Paul that too from took bond both HSI there's the are margin and there's the two font so return and make our luncheon exactly as we can a little bit slow a little bit slow add a bit more power two farms like slip there are those who start to come yeah check the cross trap 1.36 that's pretty good I think I'll just turn to to match that mystery drift that we had on inbound once again I'm working two point six on the diagonal distance again it should correspond although the distance in cross tracks vote in Iceland just coming up to 2 the distance my bike served in advance here point five and 2.62 the team in the back as I go start the right there and once again noticed the distance when I start at the time so once again I already know for a fact this is going to be a and just fly it out to complete the demonstration but essentially that's the end part one of this injury for at the bar and so in part bad to show some and for procedures we'll start doing ten more seconds according to my stopwatch five seconds and there's a minute there's the flip I don't think it gets much better than that I'll see you again part 2 you

Channel: Ray Preston

Views: 47,642

Rating: 4.8068967 out of 5

Keywords: IFR, Hold, GNS430, Instrument, rating, flight, flying, airplane, learn, to, fly, philosopher, pilot

Id: 4H7QcWCDIzQ

Length: 22min 42sec (1362 seconds)

Published: Fri Dec 23 2011