No more ‘dive and drive’ instrument approaches

August 20th, 2013 by Max Trescott

“Diving and Driving” on instrument approaches is dead. So are some of the pilots who used to use this frequently taught method for flying non-precision instrument approaches. If you didn’t get the memo, you’re not alone; some CFIs are still teaching this outdated practice even though the FAA announced—in 2001—that our industry should discontinue “dive and drive.”

Quoting from my Max Trescott’s GPS and WAAS Instrument Flying Handbook, non-precision approaches

“resemble a series of steps, like those found in a staircase, and nothing prevents you—other than your good judgment—from descending as rapidly as possible at each step. “Diving” at each step was originally thought to be advantageous on the final approach segment, since it allowed more time to “drive” level at the MDA while looking for the airport.”

Hurrying to get to the MDA to “look for the airport” had some merit before GPS-based instrument approaches became prevalent. One corporate pilot told me he felt lucky to come within half a mile of an airport when flying NDB approaches with an ADF receiver. But the airport could be on either side and pilots had to look left and right to search for it while flying at minimums. VOR approaches are more accurate, but still leave much to be desired.

In a GPS world, there’s far less uncertainty when flying non-precision instrument approaches. There’s no ambiguity about when you reach the missed approach point and typically the airport is directly in front of you. True, not everyone that flies IFR has an IFR-certified GPS in his or her aircraft, but the world is moving that way. For example, Garmin sold more than 100,000 of the now discontinued GNS 430 and 530 GPS receivers.

The problem with dive and drive is that “diving” at a high descent rate may cause a pilot to inadvertently lose control, or fail to level off at the proper altitude. In fact, the Flight Safety Foundation’s study Airport Safety: A Study of Accidents and Available Approach-and-Landing Aids found that the accident risk for flying non-precision approaches is five times higher than for flying precision approaches.

Quoting again from my book,

“In 2001, the FAA announced that the industry should discontinue the use of a ‘dive and drive’ process on non-precision approach procedures, since they contribute to controlled flight into terrain (CFIT) accidents, the leading cause of fatal commercial air accidents worldwide. Instead, the FAA advocates the use of procedures and training for a stabilized continuous descent on non-precision approaches. Some airlines have gone so far as to implement procedures that require pilots to immediately initiate a missed approach if they don’t see the airport when they reach the MDA; they are not permitted to continue ‘driving’ to the MAP.”

For pilots using an IFR-certified, WAAS-capable GPS, LNAV+V, which displays an “advisory glide slope” on some non-precision approaches, is a good substitute for the “dive and drive” process.  Another best practice for flying a stabilized descent is to estimate the descent rate required for each segment of an approach, by comparing the altitude loss required to the number of miles available to descend for each segment of the approach. Knowing your ground speed, it’s relatively easy to estimate the rate, in feet per minute, at which you’ll need to descend during each segment.

So spread the word: Dive and drive is dead. And if someone argues the point, tell him he must have missed the memo!

Max Trescott

Max Trescott specializes in teaching in glass cockpit aircraft. He is best known for his Max Trescott's G1000 Glass Cockpit Handbook and Max Trescott's GPS and WAAS Instrument Flying Handbook. He formerly worked for Hewlett-Packard and now is a full-time flight instructor. He is the 2008 National CFI of the Year. Visit Max’s website.

The opinions expressed by the bloggers do not reflect AOPA’s position on any topic.

  • Anne Amoss

    I was taught the similar “get down look around” method, and I still use it flying GPS approaches since I do not have WAAS. No matter the equipment, a pilot is not competent on instruments if he or she cannot fly GPS or other flavors lacking vertical guidance using the technique. Dive and drive does not mean get down to MDA immediately but to get down well ahead of the MAP (and every stepdown prior) because the MAP is very often is the runway threshold. You are protected at MDA all along the segment, and you will put yourself in a very precarious situation arriving at the MDA and MAP simultaneously when they meet at the runway threshold. If bases are near minimums you’ll either unnecessarily miss a lot of approaches or do some much more severe diving and driving to make the runway, breaking other rules in the process.

    • Old Bob Siegfried

      Good Morning Anne,

      If you arrive at the MAP while still at the MDA, and are properly prepared for the situation, there is nothing precarious about it.

      With relatively high ceilings and poor visibility, it is often advantageous to plan on circling. That is especially true if the field is poorly marked and the arriving pilot is not familiar with the area.

      Circling at or above the MDA and within the approved circling area allows a careful and thorough evaluation of the weather and the field conditions prior to leaving the MDA.

      The MDA provides that safe platform for evaluation.

      Obviously, the pilot needs to be trained as to how to properly circle and provide maneuvering spacing at the altitude pertinent to the approach. For we Category A and B users, that circling altitude can be as low as 350 feet above the official airport elevation. The runway looks a LOT different at 400 feet than it does at the now often suggested 1000 foot traffic pattern. If not practiced in advance, there is a strong temptation to fly a downwind or base leg way too close to the runway. Perfectly safe procedure as long as speeds are stable and the MDA is respected.

      Happy Skies,

      Old Bob

  • Jean Schwarzkopd

    The airlines gave up on dive and drive at least 15 years ago. We don’t much care where the MAP is. All we are interested in is the VDP. A 200,000 pound aircraft in level flight is in no position to start descending after the VDP but before the MAP. We take an instrument check every six months called “You bet your job.” The simulator check ride lasts four hours and very little of it is done with both engines operational. We must do at least one non precision single engine approach. Each time you level off on a step down you must power up the remaining engine and change rudder pressure. Then when its time to dive again you must reduce power and adjust rudder pressure again. All this while looking for the runway. Much better to arrive at the VDP descending at 700 FPM configured and on speed. On some aircraft a flaps 15 single engine approach results in a 165 knot approach speed.

    • http://? Old Bob Siegfried

      Good Morning Jean Schwarzkopd,

      The major airlines switched over to the CANPA approach because they no longer fly into challenging environments and the CANPA approach does make it much easier to land in zero/zero conditions.

      Different strokes for different folks.

      Incidentally, I feel for you if you think you have to bet your job each six months. I had the pleasure of taking those “check” rides each six months for 38 years. I always enjoyed the chance to fly the machine with various systems inoperative so that we could practice techniques rarely encountered. I was NOT betting my job, I was practicing so as to be able to handle the “What if” situations. I enjoyed the opportunity to gain that experience.

      Enjoy it while you can.

      Happy Skies,

      Old Bob

      • Jean Schwarzkopd

        I remember you Bob. You were one of those guys who arrived at 02:00 for the sim check and said. “I love these sim checks. It gives me a chance to demonstrate what a superior airman I am”. At my airline we referred to it as the “testing” department, not the “training” department.

        I guess the Mexico City, Mateo Transition to the ILS 05R, LOC out, maintain 230 til the SMO 9.2, 3/4 mile vis was not a challenge to a guy like you but I always dreaded it.

        I would say an approach that’s duck soup to one pilot is an bit challenging to another. The girl in charge of SWA 345 found her first landing in LGA a bit of a challenge. I flew exclusively into Central and South America for two years on the 72 and found some of those approaches to be a challenge. As you know the three hole was a VOR and DME only machine and a lot of those airports don’t have DME. We didn’t start using constant rate decent until I switched to the 80. It too was a VOR, DME machine and we had to calculate the VDP if one wasn’t published. If you wanted to wag it, 700 FPM seemed to work for most approach speeds. By the time I switched over to the 73 I had forgotten all about the dive and drive. The FMS made it so simple a cave man could do it. Even I could do it.

        • Old Bob Siegfried

          Good Morning Jean,

          Does the fact that I appreciated the chance to practice emergencies and normal difficult procedures really imply anything at all about my opinion of my personal competency?

          I think it means that I was fortunate to work for a company that understood why we received that semi annual training.

          I can agree hat the incidents you cite show evidence of a lack of sufficient training or an effort to accomplish something that was outside the normal expected performance.

          Is that not why we take training in the first place?

          Many of us do fly into small out of the way airports for which finances do not justify major expenses to accommodate airline type operations.

          It is my carefully evaluated position that the classic Dive and Drive (A derisive term that does not properly reflect the precision of the technique) allows us to develop techniques that can be taught to allow operations safely at those airports.

          I did fly copilot on the Douglas DC-3 shooting approaches via the low frequency range stations that resulted in the need to circle to get to the runway. The techniques that were taught to make those approaches safely still work well today for we who have the need.

          Flying the level flight segments, as designed, will result in a higher percentage of successful completions of the approach. If there is a record of more accidents using the Dive and Drive (And I do NOT think the record shows it that way) it is evidence of the lack of proper training.

          Happy Skies,

          Old Bob

          PS John Collins always says it better than I can

  • http://northeast-planes.com Elliott Arthur

    Another example of an “expert” in aviation. Y’all know what an expert is, don’t you? X being the algebraic quantity for the unknown, and a “spurt” being a drip under pressure.

    “The problem with dive and drive is that “diving” at a high descent rate may cause a pilot to inadvertently lose control, or fail to level off at the proper altitude.”
    Any pilot who cannot level off at the MDA after descending at an appropriate rate of descent for the approach being flown, is either improperly trained, not proficient, or not even current for IFR, and probably all three. It isn’t the “diving” that causes the pilot to lose control or level off properly, its the pilot’s competence or lack thereof that causes such problems.

    As for this being a “GPS world”, I know a lot of pilots who still operate IFR with nothing but VOR’s and DME. If y’all want me to give up “dive and drive”, feel free to buy me a GPS for each of my aircraft.

    So, a scenario, Mr. Expert: Private pilot, instrument rated, flying his trusty Piper Archer. Its a VOR approach, no DME shown on the IAP, and the final course 30 degrees off the runway heading. There is no VDP either. The VOR is on the North side of the airport, but the approach course is Northwesterly, meaning there is no FAF. The minima shows an MDA of 4200, Visibility required of 1/2 mile, and the HAT is 548. The published altitude for the PT is 5600. There are MIRL’s on the intended runway, but no approach or REIL.

    So, using your method described above, please tell me the descent angle required so that the airplane arrives at the MDA, at the point where the runway will be visible to the pilot, without violating any FAR’s, such as blowing thru MDA on the descent or descending below MDA without the required visibility. Oh, and I forgot to mention the weather is 600 overcast, variable to 700, winds favor the intended runway at 10 knots, but there is windshear at 1000 feet of 80 degrees and 40 knots.

    Next question, same weather, GPS LNAV approach, FAF is 4.8 nm from the MAP, VDP is 1.1 nm from the MAP, MAP is the runway threshold. Intermediate altitude is 6300, MDA is 5100, required visibility is 1 mile.

    By all means share with us your answers here on this site with another blog. I am really anxious to read them.

    Now I’m not gonna argue that one should use the dive and drive method flying 737′s. BUT, an awful lot of GA aircraft don’t have the benefit of the level of avionics and autopilots that big iron has. But then, I haven’t seen any really big iron flying these two approaches either. So, I’m gonna have to ask the big iron drivers a question. What happens if you do have to fly one of these two approaches, especially the first one?

    • Craig Jackson

      Agree 100% Elliott,

      This kind of attitude is, IMHO, a big part of what is wrong with general aviation today. The attitude that if one doesn’t have the latest wiz bang moving map GPS navigator they are somehow unsafe and are putting their life and the life’s of their passengers in peril really ticks me off. I don’t know Mr. Tresscott…. I’m sure he is the s*%t when it comes to G1000′s, but perhaps if he spent some of the thousands needed to install and update his glass he wouldn’t have this illogical fear of flying a non precision approach.

      I too know many people who fly all over the country with VOR’s and they do it safely and without fear. Sadly, many of these same pilots are slowly leaving aviation (and prospective new pilots are scared away) due to the constantly increasing costs… not the least of which is the perceived need to buy a $15,000 piece of avionics equipment to be “safe”. I am fortunate enough to own and fly a personal airplane with my family. I fear my son will not have that opportunity when he is grown up.

    • Chuck Cox

      I agree 100% with Mr. Arthur…

      “Any pilot who cannot level off at the MDA after descending at an appropriate rate of descent for the approach being flown, is either improperly trained, not proficient, or not even current for IFR, and probably all three. It isn’t the “diving” that causes the pilot to lose control or level off properly, its the pilot’s competence or lack thereof that causes such problems.”

      I’m not a CFI or an airline pilot. Im just an average joe 2000 hour instrument rated Private Pilot. I don’t agree that dive and drive is dead. A pilot should be prepared to do whatever procedure is most appropriate and safe for any particular situation and equipment availability.

    • http://www.g1000book.com Max Trescott

      Elliott,
      I agree, the problem is that some pilots fail to stop diving until it’s too late, which is why the FAA now advocates stabilized approaches for all types of non-precision approaches. I’ve posted FAA docs elsewhere here in the comments section that go into detail on why they believe the industry should get away from dive and drive.

      No, it’s certainly not an all GPS world, and if I were to rewrite this post, I’d remove those words, because I inadvertently made it sound like stabilized approaches are only appropriate for GPS approaches. As I said above, the FAA would like to see stabilized approaches replace dive and drive on all non-precision approaches. And when you find someone passing out free GPSs, please let me know—you should see what passes for navigation equipment in my VFR-only plane.

      Is the VOR approach you describe one you fly? Which approach is it, and how do recommend flying it?

      Craig, I hope we get to meet sometime! I’m sorry if I gave the impression that people are unsafe without the latest technology, because I don’t believe that. My only point was that the FAA believes fewer pilots will crash if they use stabilized approaches on all types of non-precision approaches instead of the dive and drive techniques that many of us were taught. Check out the FAA docs I posted elsewhere. Ironically, while I teach in very nice glass planes, my own plane is VFR only. I would be scared to death to fly a non-precision approach in it! BTW you and I share the same fear—that the next generation won’t have the same access to general aviation that you and I have had.

      Chuck, sadly there are a number of incompetent pilots flying around. I didn’t used to believe it, but as a CFI I now come across them. There are also many excellent pilots who occasionally make mistakes. The accident record suggests that flying stabilized approaches is safer (and probably easier) than dive and drive, which is why the NTSB and FAA are advocating it.

      • http://northeast-planes.com Elliott Arthur

        Max, the first approach I discussed is the VOR RWY 30 to Goodland, KS. The second approach is the GPS RWY 11 approach to Akron, CO.

        Please answer the following questions.
        1. So, a pilot has done all the calculations needed to fly your stabilized approach, but I’m wondering what winds he should use to calculate his groundspeed inbound from the FAF, since that variable is a major factor in the descent rate required.

        2. Last time I checked, the winds tend to change during that last 2000 feet AGL. So, unless the approach is flown with an autopilot, the pilot must manually change his pitch and / or power constantly during final approach to maintain the required descent rate, which also changes as his ground speed changes. How exactly is this better/safer than descending at a pre-determined descent rate, leveling off at MDA, and driving to either runway in sight or MAP?

        3. Keeping in mind that it is a violation of FAR’s to descend below MDA without the prerequisite visibility and either approach lighting or certain items in the runway environment in sight, how exactly does one execute a stabilized approach on a constant glide path, arrive at MDA, but not descend below it, in minimums weather? Correct me if I’m wrong, but aren’t you going to have to start the missed approach procedure by initiating a transition to climb some 10-20% of descent rate ABOVE MDA to avoid violating the regs? The MDA is NOT a DA, which allows you to start the Missed Approach AT that altitude.

        Now I don’t know about you, but I have flown many approaches over the last 23 years where I did not “break out” until within 100 feet of minimums, and there have been a few where I broke out or finally caught sight of the approach lights or REILs in one case, just as my hand tensed on the throttles to GO. There have also been a few approaches where I caught sight of the field after I initiated a missed, meaning the required visibility was not present.

        Given the above experiences, I would like to know, how many of the accidents attributed to “dive and drive” were actually situations where the approach was flown inappropriately on purpose? I know of one here in NE Colorado that killed all aboard. They made repeated attempts to get in on a GPS approach in icing conditions. A witness said he heard them pass overhead multiple times, but invisible in the clouds. The last time he heard them, he could see them just below the clouds, and then the airplane suddenly pitched down and impacted seconds later. It would appear they flew the last attempt below MDA, but iced up the plane and tailplane stalled. I heard of a pilot who bragged that he often would check the plate for obstacles and descend a little extra if he needed to in order to get in during ugly weather. I have read a few accident reports where it appears that this kind of thinking was the real cause of a crash, not the dive and drive approach itself.

        Now, I use the analogy with my students that we all have $10 worth of brain power. An instrument pilot must be able to fly the plane with about $3, leaving $2-3 for navigation, $2 for communication, and still have $2-3 left for abnormals and emergencies. That means make the passengers shut up, pre-plan your approach as much as possible, and use techniques that minimize brain power requirements as much as possible. Having read all the comments herein, I think that, IF you don’t have an auto pilot capable of flying the stabilized approach, nor a reliable glide slope indication to assist you, in many cases you will find yourself using $12 of that $10 brain trying to arrive at the airport ahead of your airplane. That is a recipe for a missed approach when you could have gotten in safely and legally, or violation, or an incident or accident.

        Lastly, I see a lot on here about what the FAA recommends. However, I seem to remember a year or so ago getting a notification from the FAA wherein they discussed how frequently obstacle clearance cannot be assured if an airplane is allowed to descend below published altitudes for step down fixes on an approach. I thought that unnecessary advice until now, when I realized that if a pilot determines his own glide path on a non-precision approach, I can see where it would be easy to descend through a step down altitude inside the FAF, or even outside the FAF out here in mountain country, and find yourself inside one of those Cumulo Granite clouds.

        So, thank you for the exercise in reminding me of why I teach what I teach. I enjoyed it tremendously. However, I will continue to teach “dive and drive” for those approaches that do not offer a published glide slope and DA. A student will always be able to fly the big iron later in his career using the techniques required by his employer, as its just another autopilot coupled ILS in terms of technique. And, just FYI, I teach and use a descent rate that will get me down on the MDA .5 to 1 mile prior to that point on the approach where I must see the required items or not land. That is not necessarily the VDP and it sure as H is not the MAP. That descent rate is usually pretty close to 800 to 1000 feet per minute, easily managed by any competent pilot in any airplane up to and including a Beech 1900, based upon my experience.

        Elliott A. Arthur, CFI IASMEL
        (Instrument Airplane, Single, Multi Engine Land)

  • http://? Old Bob Siegfried

    Mr. Trescott and others who promote CANPA approaches are willing to lose the flexibility provided by the ancient dive and drive approach. It DOES take additional training and discipline to properly use the benefits of the dive and drive technique Following the “advisory” glide path will often result in a missed approach in conditions where a properly flown dive and drive will result in a safe IFR arrival.

    Why do you shoot IFR approaches?

    I do it because I want to land safely. I am willing to practice and maintain proficiency in a procedure that will give me extra flexibility. If I do not wish to maintain IFR proficiency, I will only fly in VFR conditions. I do not wish Mr Trescott or any other person to denigrate the use of older procedures just because they take a bit more training. It has nothing to do with accepting more risk, just a different procedure which can result in a safe arrival instead of a miss.

    Happy Skies,

    Old Bob

  • http://? Old Bob Siegfried

    Good Morning Elliott,

    May I take this opportunity to make a comment in support of your position?

    There are many challenging environments at which steeper approaches and relatively high rates of descent to a nice smooth landing are the better choice than the now ubiquitous CANPA approach. As is true of all flying, to execute those techniques, we do need to understand the problem, train properly, and execute correctly.

    One example of a steeper approach is the 5.5 degree glide path used in England at the London City Airport. It does take dedicated training to use those approaches, but they are are performed in what some folks might call heavy and fast machines.

    We GA pilots and a very few heavy iron pilots do find the need for using the allowable tools to develop procedures that will allow us to operate to and from those odd ball small and/or demanding airports located in spots where the investment in high tech approach aids is not practical.

    Sometimes the circling approach is the very best way to go and at other times a well planned 6 degree approach angle works just fine. The now ubiquitous 3 degree glide path was developed to accommodate automatic landings. Four and a half degrees makes for a very comfortable approach in every airplane I have flown and six degrees is great for anything with an approach speed below 120 knots.

    All it takes is the airmanship we all strive to maintain.

    Happy Skies,

    Old Bob

    • Jean Schwarzkopd

      Interesting to note here Bob. My 737 and Beech Jet type ratings both say “circling approach not authorized”. Our airline minimums for a circling approach in the 72 was 1000 feet. I don’t think I ever did one and the tendency to fly downwind too close to the runway is great.

      • Old Bob Siegfried

        Good Morning Again Jean,

        I have sixteen type ratings (Douglas DC-3 through Boeing 747) listed on the back of my ATP and none are restricted against circling approaches though I believe it is true that the FAA will not issue the circling authority if it is not demonstrated in an airplane on the check ride.

        A multitude of type ratings is an evidence of age, not competency.

        Happy Skies,

        Old Bob

        • Jean Schwarzkopd

          Way back when, we took check rides in the airplane. Now we don’t get to see the real aircraft until it’s loaded with people and we are heading out. I think the side vision in the sim was not good enough to demonstrate a circling approach and since the airline had a 1000 foot minimum it would have to be VFR anyway. We did demonstrate a circling approach in the 72 sim and it had no side vision but it was one of those 90 270 deals and I don’t think anyone actually did them.

  • Jean Schwarzkopd

    A friend of mine, who is also retired from the airlines, recently wrote an article on the subject of non precision approaches. Hugh is typed in the 727, 737, DC-10 and the MD-80. He also flew the Airbus 300. Hugh is now a check airman for the Turbo Commander.

    The Final Descent

    The NTSB, FAA, AOPA, and NBAA have stated that an accident or incident many occur at any point from taxi to takeoff or while enroute or cruising or during descent to landing. These organizations then categorize these accidents or incidents and use that data to determine trends. This data indicates that pilots are having a difficult time in the descent, approach and landing phase of flight.

    For ever flight whether it is a trip around the traffic pattern or a space shuttle mission, there is both a lateral and vertical component of flight. Data has shown that we have a pretty good idea how to fly the lateral component. However; this data indicates that to increase situational awareness, we must also concentrate on the vertical component. Success with vertical and lateral components should be considered “maintaining the center line”.

    The Nall Report for 2009, shows that accidents or incidents caused by pilot error improved by 10% over the 2008 figure. However, 75% of all accidents were attributed to pilot error with 19% of the accidents identified as fatal in the descent and approach phase of the flight. Adverse weather, descent and approach segments made up 50% of the accidents during the descent, approach and landing phase. In addition, 40% of the accidents happened in the landing phase but were nonfatal. Even though business and corporate flying has a better record than that of the other segments of general aviation, its accident rate increased by 10 %.

    Some general aviation accidents that occurred during descent, approach and landing phase are:

    • November 22, 2004 A Gulfstream III approaching Houston Hobby’s runway 4 in foggy conditions crashes on the centerline but short of the runway. A contributing cause to the accident included an unstable approach.

    • October 19 2005 A Hawker 700 crashed due to an unstablized landing. The
    tower offered a new runway clearance which would allow a shorter taxi distance to the FBO.

    • October 24 2004 A Beech King Air 200 crashed after a go a round in IMC conditions beyond the approach path of the Martinsville, VA airport. The probable cause was loss of situational awareness during the approach and go around.

    Some more noteworthy air carrier accidents are:

    • American Airlines Flight 1420 at Little Rock, AR… Approach and landing during thunderstorm activity.

    • Korean Airlines Fight 801 approaching Guam at night cleared for an ILS approach with glide slope out of service.

    Remember every flight consists of lateral and vertical components. Descents from high altitude in smooth air can be flown at speeds near the red line in the Twin commander. However if you expect to encounter moderate turbulence it would wise to reduce the indicated airspeed to 180 Kts. Expect to allow one mile for every 10 Kts of airspeed reduction. The definition of moderate turbulence can be found in the AIM under Pireps related to turbulence.

    The first instrument landing system to give both lateral and glide path information was designed in 1929 and first used by a commercial airliner in 1938 and then approved to be installed at six airports in the country in 1941. The ILS system has changed little in that time.

    In 2007, WAAS was introduced to aviation which provided a satellite based precision approach to many general aviation airports in the United States.

    Unbelievably for many years, pilots have been on their own to compute the vertical path of a non precision approach from the final fix to the touchdown point. According to the accidents reports, we have not been doing that well. Hopefully, with the increase in WAAS approaches available to general aviation airports we will see a reduction in the accident rate. Even with these technological changes, it will still be important to maintain situational awareness on the vertical path.

    The non precision approach has been taught and practiced for years to depart the final approach fix at an other than stable descent rate , level at the MDA and wait to see the runway or to make a missed approach based on DME or time. Imagine on a visual approach switching over to the tower 7 miles out from the runway and receiving clearance to land. Then, immediately dropping down to about 400 feet above the ground and leveling out till over the runway and making a landing. If we wouldn’t do this scenario in VFR why would we do it in IFR conditions? Do you think some one is setting us up for failure?

    Now, think about another scenario or constant rate of descent approach. The flight is cleared for the approach. While approaching the final approach fix, the gear and flaps are extended and airspeed is stable. The landing check is complete. The power is reduced for a smooth constant rate to the MDA while at the same time checking the vertical profile by applying the 3 to 1 rule. When the runway is visible the constant rate of approach can be continued to landing. If the runway is not in sight when reaching the MDA a “go around” is the only safe course of action. This scenario has been adopted by many flight departments including air carrier training programs and endorsed in the newly released FAA Instrument Training Handbook. However, there are several essential elements that have to occur prior to reaching the final approach fix. After receiving the weather information and runway assignment, the pilot or crew should Build the Approach into the FMC or GPS navigator. The next step would be to set the appropriate airspeed and altimeter Bug. Then Brief the approach and missed approach procedures. Build It, Bug It, Brief It!

    Now, you arrive at the final approach fix with gear down, flaps set and the landing check list complete and it is a lot less stressful than trying to do a multitude of tasks at and beyond the final approach fix. The later almost always results in an unstable approach.

    A technique to use for the constant rate of approach is to use the auto pilot and at the final approach fix select indicated airspeed or vertical speed mode. Multiply the ground speed by 5 for the constant rate of descent for a 3 degree glide slope. For a little higher angle of descent increase the rate of descent and likewise reduce the vertical speed for a slightly less than 3 degree angle of decent. Always monitor your altitude. At 4 miles out from the runway you should be 1200 feet above touchdown and 900 feet at 3 miles and so on. If your minimums are 450 above the touch down zone your visual descent point or go around point is a mile and a half (1 ½) remember visual descent point or go around point is height above touch down divided by 300. There is a lot of math going on during the final approach. It might be helpful to write down in the margin of the approach plate the required altitude at each mile from the runway.

    In conclusion, building the approach in the FMC or GPS, practicing the technique during all of your approaches to landing will greatly increase your vertical situational awareness during the IMC approach and landing.

  • John Collins

    Not all approaches are suitable for advisory vertical guidance which requires am approach path that is relative clear of obstacles in the visual segment. To limit RNAV approaches to only those that meet this criteria would mean the elimination of up to 80% of the RNAV approaches. I estimate this figure from examining the RNAV approaches here on my home turf of NC and SC. Almost 80% of the approaches did not indicate that they were clear on a 20 to 1 slope, which is just less than a 3 degree slope. This, in my opinion would not be a good thing. It also requires that the visibility requirements be substantially increased from the typical 1 NM which is VFR at an airport in class G airspace. Approaches to airports not served by an ILS with an approach light system require extra time to distinguish a runway from the Walmart parking lot ad a constant angle descent where the missed approach decision must be made in an instant doesn’t permit landing under what is otherwise a safe operation. As Old Bob pointed out, a dive and drive or a circling option is often the best one when flying into an airport with challenging obstacles in the visual segment as it buys the pilot the time necessary to access the situation before they commence their descent from the SAFETY of the MDA.

    The MITRE corporation conducted a study and compared the safety record of turbojet aircraft when conducting a vertically guided approach verses the dive and drive and it was clear that the former offered significant improvement in safety. They also conducted a similar study with GA piston aircraft and did not find any statistical difference in safety and in fact the dive and drive had a lower accident rate than the vertically guided approach. My point is that it is not proven that the assertion that dive and drive is a positive safety improvement for all airspace users. We in GA fly into smaller airports with fewer facilities, poorer approach lighting, shorter runways, and approaches that are not clear in the visual segment. This gives GA pilots more options to land at more airports that are closer to our destinations. Many of these approaches, including RNAV approaches are simply not suited for an advisory glidepath and it is downright dangerous to use a vertically guided approach when it isn’t warranted or the approach isn’t designed to be used with a glidepath. At night, this is particularly not a good idea as unlit obstacles can not be seen.

    In conclusion, it is my considered opinion that there is a place for the dive and drive, it must be practiced to be accomplished safely, and blind adherence to unsafe vertical guidance may be a greater threat than the appropriate use of the dive and drive. I strongly disagree with the author, the dive and drive is not dead, but you may end up that way if you blindly use the vertically guided approach on one that doesn’t warrant it.

    • http://www.g1000book.com Max Trescott

      John, I wasn’t suggesting that advisory vertical guidance, like the LNAV+V capability on many Garmin GPSs, is needed for all approaches. Instead I was suggesting that for any non-precision approach, one can compute the descent rate required for each segment and descend at that rate after crossing the fix that starts the segment. There’s no vertical guidance involved other than the vertical speed indicator; a pilot simply descends at whatever rate he or she calculates to be appropriate for that segment. There are lots of ways to compute required descent rates and some are discussed in this thread http://www.pilotsofamerica.com/forum/showthread.php?t=11789
      Hopefully readers will post their favorite ways to calculate descent rates here in these comments.

      I’d heard, but don’t know if it’s true, that the people involved in the MITRE study were surprised with the GA results and speculated that it could have occurred because of the small number of light planes involved in the study.

      There may indeed be situations where “dive and drive” makes more sense, though it’s rare in my experience, which admittedly has been mostly in the western United States. I wrote the post because I worry that more pilots will die while “diving” simply because they were taught dive and drive and are unaware of other practices.

      • Jean Schwarzkopd

        I think we might have gone off point by the use of the word “dead”. Nobody said you couldn’t use the step down but my point was you should learn to calculate and use the constant rate decent. I was on the 80 when my airline started teaching the constant rate and we all thought it was a bad idea. We had to look up decent angle, ground speed, obstacle clearance, etc. When all was said and done it turned out 700 to 750 FPM decent got the job done. Read Hugh Davis’s article, above, and try his method the next time you are out practicing approaches. It will work on any approach that has lateral guidance. No need for DME or GPS. If you have GPS with VNAV it’s very easy especially if your autopilot will couple to the VNAV and you have auto throttles. Just kidding. What I’m saying is, learn to do it and add it to the IFR tools at your disposal.

  • Max Trescott

    Thank you everyone for your comments and thoughts. AOPA asked me to keep the post to 500 words, which is why I couldn’t go into great detail. Here are some of the FAA documents that talk about the problems with “dive and drive.”
    My thanks to Ken Lane, who posted these references a few minutes ago to a Facebook discussion on the blog post:
    CDFA AC:
    http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC%20120-108.pdf

    CANPA Safety Alert:
    http://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/safo/all_safos/media/2009/SAFO09011.pdf

  • Pingback: dramático

  • Pingback: メンズ ファッション 特集サイト

  • Pingback: 史上最も激burberry バーバリー アクセサリー