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FAA, NTSB Remain At Odds On ‘Dive And Drive’ Instrument Approaches

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  • FAA, NTSB Remain At Odds On ‘Dive And Drive’ Instrument Approaches

    FAA, NTSB Remain At Odds On ‘Dive And Drive’ Instrument Approaches

    A type of non-precision instrument approach composed of a series of step-down altitudes, informally known as “dive and drive,” remains a point of contention between the FAA and NTSB following the August 2013 crash of UPS Flight 1354 in Birmingham, Alabama.

    To date, the FAA has refused an outright ban on the technique, despite nearly a decade of pressure by the NTSB. UPS separately says it plans to prohibit the practice in its pilot manuals.

    In the Birmingham crash, the crew of the Airbus A300-600 freighter had intended to use a more precise non-precision instrument approach technique known as a constant descent final approach (CDFA), but the captain ultimately resorted to a dive and drive approach late in the arrival. The aircraft hit terrain approximately one mile short of the runway, killing both pilots.

    The NTSB issued 15 recommendations to the FAA following the crash, including one recommendation calling for the agency to prohibit dive and drive approaches, a recurring theme in the NTSB’s crash investigations.

    The NTSB first asked the FAA to “develop and encourage” the use of CDFA approaches at all airports served by commercial carriers after an American Airlines MD-80 struck trees while on a dive and drive approach to Bradley International Airport near Hartford, Connecticut, in 1995.
    A type of non-precision instrument approach composed of a series of step-down altitudes, informally known as “dive and drive,” remains a point of contention between the FAA and NTSB following the August 2013 crash of UPS Flight 1354 in Birmingham, Alabama.
    AirDisaster.com Forum Member 2004-2008

    Originally posted by orangehuggy
    the most dangerous part of a flight is not the take off or landing anymore, its when a flight crew member goes to the toilet

  • #2
    The FAA does not agree, stating that while a CDFA is the “preferred method” of accomplishing a non-precision approach, dive and drive use should not be prohibited. “In certain situations, primarily dependent on weather conditions and runway alignment in combination with runway visibility, a dive and drive maneuver could benefit an operator,” the FAA wrote in its December 2014 final response to the recommendation, noting that potential problems with the technique are spelled out in an Advisory Circular.
    I'd love to know what those certain situations are.

    One commenter who claims to have 33 years of flight experience posted this:
    I "much prefer" the step-down method for a non-precision approach, as opposed to a Constant Rate Decent. The reason is simple. It allows the pilot time to level off and become established at the MDA, so he can concentrate on trying to see the airport.
    I'm trying to understand this in the context of commercial aviation. If you maintain a constant glideslope down to MDA and then level off and start hunting for the runway, logic tells me that even if you sight it after a short time you are possibly going to have to continue at an elevated sink rate (which has been a causative factor with low energy accidents) or you are going to touch down further along the runway (a causative factor in runway excursions). It might save a few approaches but it might also cost a few lives...
    “Dive and drive is prudent and safe when done correctly and under appropriate circumstances.” Based on the response, the NTSB recently closed the recommendation as “unacceptable action.”
    I think what the NTSB is getting at is that the flying public shouldn't have to bet their lives on the "when done correctly" part of that statement.

    When the FAA is not following the recommendations of the NTSB, an agency that conducts exhaustive research into the causative factors behind pilot error, what we have is a broken system.

    Why doesn't the NTSB have the authority to order FAA mandates?

    Comment


    • #3
      Because then the NTSB would *be* the FAA?

      The FAA has a dual mandate: to both promote (changed by legislation in 1996 to "encourage" but effectively the same thing) and regulate aviation. In other words, their task is to find a balance between regulating anything and everything which effectively would stop aviation completely, and regulating nothing which would result in a lot of dead people.

      The NTSB does not have such a dual mandate: they're concerned only with safety. Which is all well and good, but the *safest* possible approach would be to never let an airplane leave the ground - which would piss off a lot of people.

      Re the broader topic of "X is prudent and safe when done correctly and under appropriate circumstances."... that applies to thousands of different things in aviation. Attempting to launch an airplane into the air is "prudent and safe when done correctly and under appropriate circumstances" - but in case of AF90 it wasn't prudent or safe. Because it was done incorrectly relative to the circumstances. Yet it's done safely thousands of times every day.
      Be alert! America needs more lerts.

      Eric Law

      Comment


      • #4
        Don't go below minimums...

        ...even though they have a safety buffer.

        That even sort of includes the smooth descents as well as ILS approaches...sort of.
        Les rčgles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

        Comment


        • #5
          Why doesn't the NTSB have the authority to order FAA mandates?
          Because the FAA and the NTSB have different roles in the industry.

          The NTSB investigates and recommends on safety related matters only - they do not need to consider the cost of any recommendation, the practicality, etc.

          The FAA is responsible for safety, but also ensuring a viable industry, and that anything done is done is a way that won't cripple the industry.

          The NTSB has plenty of influence, though, and generally recommendations are accepted. Why they haven't accepted this one, I don't know. I wouldn't base all judgment on the matter on what they say publicly though.

          I'm trying to understand this in the context of commercial aviation. If you maintain a constant glideslope down to MDA and then level off and start hunting for the runway, logic tells me that even if you sight it after a short time you are possibly going to have to continue at an elevated sink rate (which has been a causative factor with low energy accidents) or you are going to touch down further along the runway (a causative factor in runway excursions). It might save a few approaches but it might also cost a few lives...
          You're combining the two approach types, where it doesn't work.

          Non-precision approaches have a minima, and a missed approach point. That missed approach point is often overhead the VOR/NDB, well beyond the point at which an approach could actually be successfully completed. Remember the Missed Approach point is purely for terrain avoidance and needs to be a 'fix' - somewhere the aircraft can be known to be.

          The idea is that after leaving a fix prior to this (usually the Final Approach Fix), you can safely descend down to the minima without hitting anything. You can continue at this altitude, without hitting anything, until the missed approach point, when you must then fly the missed approach (again, to avoid hitting anything).

          What this does mean, however, is that once you have passed a certain point along the final approach segment, it is possible that even if you get visual, you won't be able to land off the approach.

          Continuous descent on a non-precision approach is simply 'drawing' a 3 degree path back from the threshold, so that at the minima you are at the point on the final approach segment that allows you to continue a 3 degree path to the runway.

          If you are doing a 'dive and drive', you would NOT fly this path to the threshold initially. The idea is that you fly down to the minima before the point at which a three degree path intercepts it, fly a level segment, and then when you become visual, you manoeuvre and land. If you become visual beyond a point at which you can safely land off the approach, you do the missed approach.

          In the context of jet commercial aviation, there's very few occasions that you would need to do this kind of approach, although they do exist. An example is if the missed approach point is BEFORE the point at which a 3 degree path would intercept the minima. This is where you would have a 'dive and drive', and then continue visually past the missed approach point before establishing a descent to land. Another example could be for airspace reasons where a constant 3 degrees won't work. One of the last big airports where dive and drive is routinely performed is New York - VOR or GPS for 13L/R.

          RNAV has largely solved any of the real problems behind doing 3 degree approaches, but before the FAA bans dive and drive they'll need to go through and create new approaches where required, and potentially compensate operators who have lost their only approach method into some airports.

          What the 33 year veteran says about having more time to look for the airport is true, particularly in an aircraft without a 'VNAV' function. While certainly still able to be done, there is more potential for issues with CDAs in these aircraft, and I can see why some pilots would prefer the old fashioned method to ensure that they do get to the minima and have the best chance to get in.

          There are certainly operators in the world who have simply placed their own bans on 'dive and drive'.

          Comment


          • #6
            Originally posted by elaw View Post

            The FAA has a dual mandate: to both promote (changed by legislation in 1996 to "encourage" but effectively the same thing) and regulate aviation. In other words, their task is to find a balance between regulating anything and everything which effectively would stop aviation completely, and regulating nothing which would result in a lot of dead people.

            The NTSB does not have such a dual mandate: they're concerned only with safety
            No, that's absurd! The NTSB is essentially the intelligence gathering arm of the FAA. They focus on safety but with respect to practicality as well. Their recommendations are generally very well considered and not impractical. I find them often conservative.

            The FAA, on the other hand, has been the focus of whistleblower investigations about collusion with the industry at the expense of safety. I not so confident that the FAA is a disinterested body these days and I'm not comfortable with them having decisive power over NTSB recommendations.
            Because then the NTSB would *be* the FAA?
            Exactly. Why aren't they one agency?

            Comment


            • #7
              Exactly. Why aren't they one agency?
              Because it ensures that there is no (or at least very limited) commercial or political pressure on the aviation safety investigator. They are free to do their investigations and recommendations without worrying who's toes they are stepping on.

              They know to be practical, because otherwise they will be laughed out and considered irrelevant - but they do have that freedom.

              The VERY LAST thing we want is for the two to be combined!!! The separation of these two is the absolute core of the safety of the aviation industry. I'm amazed that someone with your safety mind wouldn't see that!

              Comment


              • #8
                Originally posted by Evan View Post
                No, that's absurd! The NTSB is essentially the intelligence gathering arm of the FAA.
                In your imagination, or in the real world?

                In the real world, the NTSB is a completely separate agency, with separate leadership, separate budget, and created and governed by a different section of the law than the FAA. The only possible way they could be considered an "arm" of the FAA is that they probably have the FAA's phone number in their Rolodex.

                And indidentally, the NTSB investigates accidents in a number of areas other than aviation (which would not make sense for an arm of the "Federal Aviation Administration"), and makes recommendations to many other agencies and organizations besides the FAA.

                Originally posted by Evan View Post
                They focus on safety but with respect to practicality as well. Their recommendations are generally very well considered and not impractical.
                Their own website at http://www.ntsb.gov/about/pages/default.aspx describes their mandate (in part) as follows: "The NTSB determines the probable cause of the accidents and issues safety recommendations aimed at preventing future accidents." Nowhere does it say anything about the recommendations being practical.

                Now the members of the NTSB aren't dummies, and I'm sure as professionals they try to avoid making recommendations that are completely impractical. But evaluating the practicality (/cost) of their recommendations is *not* part of their official mandate.

                Originally posted by Evan View Post
                I find them often conservative.
                No surprise there...

                Originally posted by Evan View Post
                The FAA, on the other hand, has been the focus of whistleblower investigations about collusion with the industry at the expense of safety. I not so confident that the FAA is a disinterested body these days and I'm not comfortable with them having decisive power over NTSB recommendations.

                Exactly. Why aren't they one agency?
                So you're saying that we'd be better off if the NTSB was part of an agency that "...has been the focus of whistleblower investigations about collusion with the industry at the expense of safety"?

                Although for what it's worth, being the "focus of whistleblower investigations" does not necessarily mean an agency is bad. I'm pretty sure my dogs have been the focus of "whistleblower investigations"... in a world with 7 billion people in it, no matter what you do you're going to piss *someone* off.
                Be alert! America needs more lerts.

                Eric Law

                Comment


                • #9
                  Originally posted by Evan View Post
                  I'd love to know what those certain situations are.
                  Broken clouds...

                  Imagine a chunk of clouds, just below minimums, in the vicinity of the airport.

                  But a couple miles out, on the approach path, is a spot with higher clouds.

                  The constant angle approach could keep you in the clouds.

                  But if you "dive and drive" (I don't like that term because it's gross exaggeration of a sequence of intermittent, but 100% stabilized, controlled, safely expedited descentS), you break out in the higher clouds, and then maneuver in a perfectly safe manner to a visual landing...

                  Now, let's think about broken clouds, AND a long approach with three or four step downs, and the chances of breaking out into visual conditions...

                  I think that is one of the classically cited advantages to a step down approach.

                  Second Edit: A diagram below. If you do the constant rate descent, you go missed. If you do a true, expedited step down, you break out to good visibility and maneuver visually to land.

                  Admittedly, it's a slightly special situation. Conversely with broken clouds and numerous step downs it could indeed make the difference.

                  Last edited by 3WE; 2015-04-09, 15:44. Reason: Edited to address Eric's comment.
                  Les rčgles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.

                  Comment


                  • #10
                    Originally posted by 3WE View Post
                    if you "dive and drive" (I don't like that term because it's gross exaggeration of 100% stabilized, controlled descent, just a slightly more expeditious descent)
                    I think one of us must be misunderstanding what "dive and drive" is!

                    My understanding is that basically you follow as closely as possible the altitude profile shown on the bottom of the approach plate (example: http://www.rvs.uni-bielefeld.de/publ...ep/Cali/c1.gif).

                    So it's (for example) descend-fly level-descend-fly level-descend... and hopefully touch down on the runway. That's hardly a stabilized approach! At least not for the entire sequence... you could have a stabilized final descent.
                    Be alert! America needs more lerts.

                    Eric Law

                    Comment


                    • #11
                      Originally posted by MCM View Post
                      Because it ensures that there is no (or at least very limited) commercial or political pressure on the aviation safety investigator. They are free to do their investigations and recommendations without worrying who's toes they are stepping on.

                      They know to be practical, because otherwise they will be laughed out and considered irrelevant - but they do have that freedom.

                      The VERY LAST thing we want is for the two to be combined!!! The separation of these two is the absolute core of the safety of the aviation industry. I'm amazed that someone with your safety mind wouldn't see that!
                      Ah yes, point taken MCM. I was thinking that a non-corrupt agency would be a reforming force to a corrupted one, instead of the opposite. What was I thinking...

                      Still, Why shouldn't the FAA be required to enact certain NTSB recommendations, perhaps referred to as 'NTSB Mandates'? Same reason... ?

                      Well, hopefully all the major OPERATORS have banned 'dive and drive'.

                      Comment


                      • #12
                        Originally posted by Evan View Post
                        Still, Why shouldn't the FAA be required to enact certain NTSB recommendations, perhaps referred to as 'NTSB Mandates'? Same reason... ?
                        Sometimes they are, indirectly. The NTSB can go to the Congress (which is its "boss"), present a case, and try to convince the lawmakers to pass a law that would make it mandatory for the FAA to regulate something.

                        It happened for example with the requirements for pilots in airliners.

                        --- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
                        --- Defend what you say with arguments, not by imposing your credentials ---

                        Comment


                        • #13
                          Simple minded time again. They say a picture speaks a thousand words so heres a question.....

                          If it 'ain't broken........ Don't try to mend it !

                          Comment


                          • #14
                            Originally posted by 3WE View Post
                            Broken clouds...
                            Couldn't you just calculate a CDFA down to MDA a few miles short of the runway (assuming MSA allows for that) and then 'drive' at MDA until you either find a break for a visual or hit the GS (or glidepath) to the threshold and go around?

                            Like a 'glide and drive'?

                            Comment


                            • #15
                              Originally posted by Gabriel View Post
                              Sometimes they are, indirectly. The NTSB can go to the Congress (which is its "boss"), present a case, and try to convince the lawmakers to pass a law that would make it mandatory for the FAA to regulate something.

                              It happened for example with the requirements for pilots in airliners.
                              I assure you Gabriel, we don't want to distract U.S. Congress from more important matters right now (not that they are capable of doing anything at all).

                              Comment

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