How to Fly a Non Precision Approach | Continuous Descent FInal Approach | LNAV + V
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- Опубликовано: 16 сен 2021
- We'll cover how to fly a non precision approach. Unlike a precision approach like an ILS, there is no vertical guidance on a non precision approach. Even without this though, we can still figure out a descent rate that will give us a continuous, stable path to the runway without having to make difficult changes to the airplane mid approach. This is what's called a Continuous Descent Final Approach (CDFA).
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I was recommended by a friend. I can't believe how far above the others your content lies. It's excellent work, sir.
Man I learn from you so much and feel I owe you for the great job you do. Thank you so much for your efforts.
You're welcome as always. I'm learning (Or relearning) alot through the process too.
These videos are incredible. So useful and insightful. Thank you for making them.
Precise, easy to understand, this is one of the best IFR helper videos in RUclips!!
How do you not have more subscribers, these videos are really nicely done!
Thanks! I'm going to work on non-precision approaches next and this video really helped! Thanks.
Another concise and clear explanation! Thank you.
I can’t imagine being in IMC and having to work out your ground speed to get an accurate V-apps.
Great video! Very helpful
Very well done, thanks.
Wonderful Video! Thanks
Great Video!
I believe that the Jepp descent angle calculation description around 7:50 needs more direct language about why a pilot cannot make this calculation on their own. Jepp only publishes continuous descent guidance on those approaches where that guidance continuously meets the obstacle clearance formula against the current obstacle data base. If Jepp doesn't publish this on an approach, or you are using an FAA chart, you are not free to establish your own glide path using your own math.
Most greatest video ever about IFR in my life. Just want to say huge Thank you.
Great video! Thank you. I would just add that we do have an indication of our descent angle in the cockpit if we have a flight path marker, such as with a G1000.
All your videos are helpful
awesome video thank u
thank you , so well explained i really enjoyed your video fantastickkk
Quality of of work is amazing. You helped me so much! Thank you sir. :)
Great video
Thank you sir, very clear explanation! its great that you showed both FAA and Jeppesen charts. Do all the US airlines use FAA charts or do they also use Jeppesen charts?
Great job...I've been flying for years but these presentations are clear and concise for important topics. Keep up the good work!
Will do, thanks! Glad it's not just student pilots that are getting benefit from these videos!
Great videos. Very informative and easily understood.
Thanks for watching!
absolutely love these videos!
Thanks Liam!
So helpful!
Very helpful.
Awesome video, makes it a lot easier to understand
Glad to hear it!
Great Video. Thanks
Thanks for watching Jake!
For a very close estimate of a proper descent rate for a 3 degree descent, divide your groundspeed in half and add a zero to the result. For a Cessna172 on approach at 90 kts, half is 45, add a zero, 450 feet per minute is what you should do.
Some people find it easier to multiply your ground speed by 5, end result is the same (90 times 5 is 450). That worked for me until I was flying King Airs and descending from altitude at say 220 kts ground speed. It was much easier to halve that (110) and add a zero (1,100 fpm descent) than to multiply 220 by 5 in my head.
Awesome!
thank you, thank you, thank you!!!!!!!!!!!!!!!!!!!!
These are some of the absolute best IFR training videos on the Internet! Thank you so much for making them and giving them away for free! I am sure plenty of us would be willing to shell out dollars to conveniently own the entire series.
Thanks Dwamian! Check out our full IFR course at flight-insight.com/ifr
@@flightinsight9111 Enrolled in your commercial course. That's my next mission! 🤩
Awesome!
Great video! But what if the descent angle isn't published? Is there an easier/quicker way can I calculate it ?
I love all of your videos. They are so clear and every time I have a question, you have a video to answer. What flight simulator do you use?
Thanks so much! Most of the videos use MSFS 2020, and some of the older videos are with Xplane11
Awesome videos man. What program are did u use to change the needle position on tachometer?
Thanks a lot for this explanation about the NDB approach it's very detailed easy to understand and it will be very helpful if you do a video in how to intercept a track using a Fixed-Card ADF inbound and outbound and the tips of making the relative Bearing easier to understand because this subject is one of the most challenging in IFR flying i should mention that there is no videos at all on youtube addressing it properly except a flight instructor called Ray preston but with low quality and poor sound video .
I think that would be a great video, thanks!
I would love to see this type of clear explanation of an RNAVB approach to a place like 0W3 which has a circle and land feature.
You are a bomb mate 💣
Great graphics. What platform do you use for graphics ?
As an Australian I found this interesting, here we only do this style of NPAs, there’s no dive and drive taught here. For GPS LNAV (no WAAS in Australia yet, don’t ask, its coming soon) we have target altitudes every 1 nm during the approach to provide the vertical guidance from the IAF to the MDA. We aim for a stabilized approach from the descent point (normally at IAF or between IAF and FAF) with minimal power and pitch changes. AirServices (our airspace operator) has aimed to make each approach as close to the same as all the others as possible. As such it is normally 5nm from airfield to FAF, 5 nm from FAF to Intermediate approach fix (IAF) and then usually up to 3 Initial Approach Fixes (IAF again) 5 nm back again.
What is the difference between CDFA and CANPA ( continuous angle non precision approach) ??
When landing in farms for example with no approach and low visibility, I start my approach with 2000AGL, start to descent 6nm, reach 3nm with 1000AGL, then 1.5nm I have to be at 500AGL, until reach minimal 200ft, I do it when I know the region around
I’m not a pilot, but I really enjoy flying and love learning the details. If I can ask a question, where do all the names come from like BENDR/ELUCO/FEMOD and so on? How are these locations named ? I understand the why, just not sure how they get their names.
Question on the LNAV+V - At what point does the vertical glide path intercept the MDA? Isn’t it at the VDP if there is one? This is FAA question on the IPC Guidance document...Thanks!
6:53
For an approach without vertical guidance, if we don’t see the runway environment at VDP, we don’t go miss at VDP. We continue to maintain MDA until MAF and go miss.
True, but why waiting for the MAF? What if you see the runway between the VDP and MAF?
@@Virtualmix Think about the very definition of VDP. VDP is the point where normal descent can be made from MDA. You will see on-glideslope visual cue from VASI or PAPI at this point(not always but mostly)
Now, when can you descent from MDA? Refer to FAR 91.175(c)
To descent below MDA, you have to have
1) Flight visibility, 2) Runway environment in sight, and 3) be at normal position to land.
Once you pass the VDP, that means you are not at normal position to land. Therefore, although you have runway environment insight between VDP and MAF, you should go miss.
@@kunheelee3803 That makes sense now. Thank you for taking the time to explain in details, I very much appreciate it!
@@Virtualmix My pleasure.
Your video lectures are generally excellent. They a nice review for those of us that have been flying IFR for a little bit as all continue to learn, and a great way to learn if just starting. I would like to suggest one correction this video. You reference the use of the Rate of Decent Table in the Chart Supplement for localizer only approaches. This is a nice resource for many reasons and all IFR pilots should have easy access to it. However, when correlating the angle of decent on the glide slope with the ground speed, I believe the table shows a rate of decent in ft/nm and not ft/min as you stated. Of course, this is what we want as our VSI reads ft/min. To obtain ft//min, multiply the ft/nm by 1.5 (90 nm/60 min). I think I have this correct, apologies if not. Please keep up the great work.
Thanks for the nice comments Joseph, and for catching this item. It will be fixed in the final course!
I think you are not correct, Joseph. For a given descent angle, the ft/nm is constant. But the ft/min changes with the ground speed. All the table does is give you some precalculated values. The columns below the ground speed row are therefore in ft/min.
On the other hand, if you are in low IFR conditions, the dive and drive method will get you to MDA sooner and since the lights are brighter at the MDA than higher up, you are more likely to see the lights and be able to continue the approach to a landing. (see video on this subject by Rod Machado).
In your first example you show going missed at the VDP. While you may plan to go missed if you don't see the runway at that point, you must carry on to the end of the runway (which is the actual missed approach point) before beginning the missed approach procedure, correct?
Correct. It looks like the animation has the aircraft climbing out at the VDP, but with the MAP defined as the runway threshold that is where the initial climb out should begin. Thanks for that!
But doesn’t a CDFA exclude straight and level segments even if missed approach is to be carried out? I believe that’s where the difference between a CDFA and a non-CDFA missed approach lays. For example in a non-CDFA you would fly straight and level from the VDP to the MAP and then start climbing, whereas for the CDFA missed approach you would start climbing at the VDP in case the runway is not in sight since CDFA approaches never include a straight flight segment.
If WAAS is available, as mentioned by the narrator, you will get a V+ or LNAV +V reference glide path that uses a 3.0 degree angle. On this approach with a 3.04 degree angle, following the reference V+ glidepath will put you below the published approach angle which will cause you to be too low at each of the fixes. Well done about talking about the V+ glidepath and the cautions when using it. Following the V+ path below MDA at night may result in a CFIT type of accident. Always follow the VASI or PAPI from MDA to the runway, especially at night, in low viz, or with a displaced threshold. I just wrote a tutorial on flying the V+ glidepath for both the Cessna and Piper Owner Magazines that will appear in the September issue. In it I mention that the V+ reference glidepath is based on a 3 degree angle to the runway threshold, and does NOT compensate for displaced thresholds. For example, if flying the V+ path to a runway with a 1000 foot displaced threshold, you will be well below the normal approach angle. And keep in mind the V+ glidepath does not guarantee obstacle clearance, so be very careful using it.
Hi Joel! Jeppesen states their advisory glidepath, or +V as it shows up on GPS annunciators, is calculated using the visual descent angle (VDA) which on this approach is 3.04°. This means the advisory glideslope doesn't always follow a standard 3 degree glidepath, and this is a good example of that. Also per Jeppesen, the advisory glidepath is computed using the VDA from the runway threshold at the crossing height (TCH), so any displaced threshold doesn't affect where the advisory glidepath guides you to. You can see both these things in action flying the RNAV 33 into KGON in the sim, both a nonstandard VDA and a displaced threshold of about 3 or 4 hundred feet. I hope this helps with your article!
I have personally flown the V+ glidepath to runways without any published glidepath in day VFR conditions and have seen the PAPI with all red lights at the FAF even though I was perfectly on the V+ path. this was because there were obstacles near the threshold. Jeppesen makes approach charts, and have no input into how the navigation system in my plane works. If the PAPI/VASI is set, for example, at 4 degrees due to a displaced threshold and obstacles, and you fly the 3 deree V+ glidepath VFR at night, you will collide with those obstacles. What I know I learned from actually flying the V+ glidepath into uncontrolled fields, and what you are teaching is from the classroom and training manuals. To prove my point, look at the RNAV approach to KTHV, York PA and mentally fly the V+ path and you will see that 1. there is a note that says "VGSI and descent angles not coincident (VGSI Angle 4.50 (degrees) /TCH 20". and 2. the note that says Straight-in RWY17 NA at night, Circling RWY 17 NA at night". This is due to unlighted obstacles close to the actual runway threshold, which is why the runway is displaced, and why you cannot fly this approach at night. I once flew this approach in day VFR conditions following the V+ glidepath in my Pilatus, and at the FAF I saw all red lights on the PAPI and quickly realized that if I continued to follow the V+ glidepath to the displaced runway threshold, that I would collide with the hill and trees off the end of the runway. This experience was my inspiration for writing the article. The V+ glidepath in my Honeywell avionics did not compensate for the required 4.5 degree approach angle, as you claim it would.You need more actual flying experience and less classroom BS. The V+ glidepath in an airplane's navigator is set for a constant 3 degree angle and does not change because the approach being flown requires, for example, a 4 degree approach angle. If you see the statement on the approach chart that says "Visual Segment-Obstacles", and you fly the V+ glidepath all the way to the runway threshold VFR at night, or IFR in low viz, You will have a CFIT type of accident, guaranteed.
knots * 1.151 * 5280 / 60 * sin(degrees), just pull up a calculator during prep
1.151 = conversion of knots to mph
5280 ft in mile
60 minutes in an hour
knots * 1.151 * 5280 / 60 convert your forward speed to feet per minute, then sin (degrees) converts it to downward speed
You still need to verify crossing any stepdown fixes at or above their published minimum altitudes.
For the first approach is the hold mandatory? Or if you are aligned for a straight in is it NoPT?
Good video, there is one small issue though, going missed at VDP on a non precision approach. In real life, yes it would make sense to go missed around vdp if you cant see the runway because a stable approach to land cannot be maintained however, youll see the missed approach point on that chart is the runway end, and on a checkride, you must fly to the missed approach point before going missed. You should hit vdp, verify you cannot see the runway, and then continue on to the missed approach point before going missed.
Yes, thanks. That definitely doesn't come across correctly in the video! It's an old one, and is up to date in the course.
Do you by any chance have the reference about the fact that you mentioned about gps vertical guidance? Any faa source that says you still need to be above specified altitude even if your vertical guidance tells you to go down during gps approach that would make you go below the mentioned altitude before it’s fix?
There are GPS based approaches with vertical guidance. LPV and GLS approaches do contain vertical guidance and are flown like an ILS, GLS in particular is capable of CAT IIIb operation but is currently "only" certified for CAT I minima. Some FMS equipped aircraft can fly RNAV approaches with a temperature compensated pseudo glidepath, but in that case the minimum altitudes at each step down fix are hard limits and you have to stay at or above those altitudes. Even more important if your FMS can fly those approaches only without temperature correction, in which case you have to distinguish between the LNAV/VNAV minimum which is safe down to a minimum temperature noted on the chart, and LNAV only minima where you are responsible to adjust all altitudes based on current temperature yourself.
Bro do you have a ground school? I’m doing the gleim ground and this is WAY EASIER TO DIGEST and understand!!!
We do! Check it out at flight-insight.com/ifr
This is a really great RUclips channel with excellent content, but this subject compels me to share an opposing point of view. I realize this will sound like heresy to those who accept what the FAA and other aviation authorities now recommend, but I do not believe the CDFA technique is easier or safer than the original technique pejoratively called "dive and drive" by CDFA proponents. Not only have I used both methods myself, but I have I trained and observed dozens of pilots during hundreds of non-precision approaches in everything from small supersonic jets to 4-engine jumbos, and I have seen more pilots bust the MDA while using CDFA than the standard method. This is because there is no vertical guidance, and the pilot gets so busy trying to calculate the vertical profile that crosscheck of the MDA itself suffers.
An approach without vertical guidance is inherently different, and the approach is not stabilized just because the descent rate is. The most important element of the NP approach to stabilize is level flight at the MDA. That is safe. It is also easier in terms of mental processes. The pitch and power changes necessary to cross the FAF on speed, initiate controlled descent (not dive) to the MDA, and level off at the MDA are simpler than constantly doing math to decide if you are always at the right height for you distance from the runway. After crossing the FAF there are two pitch and power changes until the MDA/VDP, unless a stepdown fix becomes a factor, and most of those do not require an additional level off unless you really did ‘dive” from the FAF. If you don’t break out, you do not have to arrest a decent rate to transition to the missed approach, which is easier in terms of aircraft control (for those who find pitch and power changes challenging) and safer in terms of obstruction clearance. If you see the runway and decide to land, you then make another known pitch and power change to a visual glidepath. People who find this so challenging as to be ‘less safe’ just need more practice flying.
Yes, transitioning from instruments to a visual glidepath is the most challenging part of a non-precision approach due to lack of normal visual cues. But the idea that the CDFA approach makes this easier and safer is based on trust that the descent rate you have been maintaining on instruments won’t need much adjustment. That is true only if you are very skillful or lucky, and as I am already positing that the lure of CDFA is that it requires less skill, luck is often a larger factor than desired. In practice just as easy to use those same instruments to set the descent rate when you transition from the MDA. From the VDP simply pitch to 3 degrees lower what held level and set power accordingly. You don’t go from all instrument to all visual reference, you start with a composite crosscheck until your glidepath is stabilized.
Another fallacy is that “We should gain sight of the runway slightly before the MDA". Not if the weather is at minimums, or you just happen to decent into a low piece of scud at that point. Being level at the MDA prior to the VDP/MDA allows more time to search for and acquire visual references while the airplane is in stable level flight. Once you have contact with the airport environment/runway, momentary loss of contact in a patch of scud will not force you to go missed, so you are more likely to land from the approach. If you lack sufficient cues to descend until inside the VDP, you can still land by accepting a steeper glidepath (if you have sufficient visual references and skill) or a longer landing (with sufficient runway length). This may not sound like a big deal to pilots who are deterred by pitch and power changes and would rather fly to an alternate that has an ILS, but it is a big deal when you don’t have such options and absolutely have to get into this airport.
I believe the CDFA method is not safer, but simply more comfortable for pilots who rarely fly a non-precision approach, and when they do fly one the weather is not down at minimums. In fact, in my last years of airline flying I would see senior captains fail to demonstrate proficiency at non-precisions simply because they only got to see one during every other recurrent simulator ride. Meanwhile I was constantly hand-flying flying such approaches as a reservist, and I refused to adopt the CDFA (AKA CROD) technique being championed by less experienced or less proficient pilots. Those guys are now making policy, and if I were not retired, I would probably be forced to fly that way, so I’m really glad to be out of the game. Thanks to anyone who listened.
Thanks for this perspective! I was actually getting into a discussion about this the other day with a few buddies who fly 135, whose company has them do dive and drive, probably for the reasons you've indicated, but more than likely because the aircraft they fly don't have advisory glideslopes which make CDFA a bit easier. My compromise is to rather than do the heavy math to try to compute a perfect CDFA rate, know what rate will get to the MDA a bit before VDP/decision point, giving me time to level off and decide. As an instructor, I've taught CDFA because I've seen too many pilots get unstabilized with pitch, power, and yaw changes while trying to hold the needle centered. In instrument flying, I'm a big fan of doing as little to the plane as I can. Thanks!
And I'm a fan of making the process as simple as it can be, and in my experience pitch and power is simpler than CDFA. But I do have to clarify that I am not vehemently opposed to CDFA when the airplane can compute and display a desired glidepath which is simple for the pilot to follow. I think this is why airlines are so big on the CDFA, and I would agree that they are right to do it when they are equipped for it, especially in light of the lack of proficiency in NP approaches.
The mistake is in applying CDFA in airplanes that are not equipped to provide the pilot with such guidance. Even if so equipped, CDFA would still not be my choice if flying a NP approach to absolute mins at an island destination with no alternate, but I know airlines are training pilots who will rarely if ever have to do that. I think pilots should still learn the old way and use the new way only when their equipment and operation make it the better percentage choice.
Thanks for listening. You have a great channel here.
Great video. Don’t forget you still have to keep the needle centered. Just sayin….
If you can fly at freeway you can fly anywhere 😂🤙🏽