LOM approach procedures
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LOM approach procedures
Hello everyone, I'm a novelist who writes action-adventure books about aviation (well, actually, putting my first book through the final round of editing before publication while at the same time doing research for the sequel). In this book, there is a scene where my heroine has to make an LOM approach to a small tundra airstrip in a strong gusty crosswind in barely adequate visibility (ceiling 500, visibility 1 mile in a pouring rain) while critically bingo-fuel (only 10 min. reserves at moment of touchdown). My question is: what are the proper procedures for lining up on an LOM approach? I've tried to look at different approach plates, but they have three different types of procedure: the one for Pueblo (and several other airports) says to cross the LOM, fly outbound, make a barb-type procedure turn and fly inbound on runway heading; the one for Oostende says to cross the LOM outbound, make a teardrop at the LOM and then fly inbound; and the one for Smolensk says to cross the LOM inbound, fly a timed upwind leg, turn crosswind when past the departure end, turn downwind when the LOM is at 8 o'clock, turn base and start descent when the LOM is at 7:30, then turn final to runway heading when the LOM is at 9 o'clock and maintain MDA until crossing the LOM inbound. (The chart for Berlin Tempelhof is similar, except that the LOM is off the departure end instead of the approach end, and you cross it going crosswind and fly a timed crosswind leg.) Which of these 3 1/2 procedures is the right one? Or are all of these acceptable? For the blind landing scene, I used the Smolensk procedure flying into Coral Harbour runway 34 from the southeast; is that right, or do I have to change the procedure? Thanks in advance!
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For the 'tundra' ignore the Eastern bloc procedures. Any sort of reversal (past the beacon outbound) to establish inbound back over the beacon will do. The 'barb' you describe is an 80/260 procedure, the other as you say a 'teardrop' - that is the easiest to write about!
Procedure is normally called an 'NDB approach'.
Procedure is normally called an 'NDB approach'.
I also haven't flown into "Tundra airstrips", but have flown into a couple in fairly remote locations which used solar panels to charge batteries for the NDB.
But that was twenty something years ago - nowadays wouldn't GPS be more likely?
But that was twenty something years ago - nowadays wouldn't GPS be more likely?
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Apologies in advance, I haven't looked at any of the procedures. Now that's out of the way I'll have a stab at answering!
LOM stands for Locator Outer Marker. There is no such thing as a LOM approach, a LOM is a (defunct) part of an ILS or part of an (almost defunct) NDB / VOR approach. The locator part is usually an NDB (Non Directional Beacon) but some have been replaced by VORs (VHF Omnidirection and Range). These procedures generally predate the use of DME (Distance Measuring Equipment) or are used as a backup. The basic idea of them is as follows...
- Fly to LOM and enter hold if required.
- If track reversal is required (you're facing away from the runway) perform a base turn or procedure turn. These are the discrepancies between the procedures you have outlined. There are a few ways of making that 180 degree turn. You have to carry out the turn as described for that approach otherwise you may go outside the protected area.
More details here
Instrument approach - Wikipedia, the free encyclopedia
- Fly inbound over the LOM on a set track at a specified altitude and speed. Begin descending at a rate commensurate with the speed (this is in the table at the bottom left of the Jepp plate)
- The next marker is the MM (Middle Marker) where you can check if you're too high or too low and adjust the rate of descent accordingly.
- Some airports have an IM (Inner Marker) too to tell the pilot he's very near the runway.
The signal for each marker can only be received in a narrow cone above the marker. As you fly over it an appropriate light flashes and you hear a Morse signal.
More details can be found here
Marker beacon - Wikipedia, the free encyclopedia
Hope that helps.
LOM stands for Locator Outer Marker. There is no such thing as a LOM approach, a LOM is a (defunct) part of an ILS or part of an (almost defunct) NDB / VOR approach. The locator part is usually an NDB (Non Directional Beacon) but some have been replaced by VORs (VHF Omnidirection and Range). These procedures generally predate the use of DME (Distance Measuring Equipment) or are used as a backup. The basic idea of them is as follows...
- Fly to LOM and enter hold if required.
- If track reversal is required (you're facing away from the runway) perform a base turn or procedure turn. These are the discrepancies between the procedures you have outlined. There are a few ways of making that 180 degree turn. You have to carry out the turn as described for that approach otherwise you may go outside the protected area.
More details here
Instrument approach - Wikipedia, the free encyclopedia
- Fly inbound over the LOM on a set track at a specified altitude and speed. Begin descending at a rate commensurate with the speed (this is in the table at the bottom left of the Jepp plate)
- The next marker is the MM (Middle Marker) where you can check if you're too high or too low and adjust the rate of descent accordingly.
- Some airports have an IM (Inner Marker) too to tell the pilot he's very near the runway.
The signal for each marker can only be received in a narrow cone above the marker. As you fly over it an appropriate light flashes and you hear a Morse signal.
More details can be found here
Marker beacon - Wikipedia, the free encyclopedia
Hope that helps.
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Agent Orange,
Several thoughts from a fellow writer and pilot:
Unless you're marketing the book to other pilots, then lean toward explaining the event in simple terms. There is no such thing as a "LOM approach." Trying to put that term in your book would be confusing even to a pilot. Instead, a slowly vanishing type of approach is the NDB Approach ("non-directional beacon"), which involves a beacon, often in remote areas. The beacon is simply an AM radio station, and uses an instrument that points to the station. Some instruments are integrated with compass features, to show the airplane heading all the time, and thus make orientation to the station a little easier. These instruments are called "RMI's" (radio magnetic indicators). Other systems use a "fixed card ADF" instrument, which is nothing more than a needle which points to the position of the beacon.
When a pilot intends to fly the approach, generally one flies the airplane directly to the beacon itself. In the cockpit, the indication is a needle which turns on a circular dial instrument. If the needle points up, then the beacon is in front of the airplane. If the needle points down, the beacon is behind the airplane. If the needle is directly to the right, the beacon is off the right wing, or in other words, 90 degrees to the heading of the airplane. If the needle points to the left, that puts the beacon 90 degrees to the right of the airplane, with a relative bearing of 270 degrees.
Another way of thinking about the NDB and staying oriented to it is to think of the instrument in the cockpit as showing the direction, relative to the front of the airplane, of the beacon. The "o'clock" position, if you will. Behind would be the six o'clock position, to the left would be the nine o'clock position, etc.
If one is to fly a particular bearing to the station, a specific course over the ground, one needs to be able to orient one's self using the cockpit instrumentation by determining one's heading and bearing on the RMI/ADF, and then timing the rate at which the needle moves to determine how far from the station one is. This gives one the information necessary to determine position (bearing and distance), and thus where to go to get on the necessary course.
If one wishes to fly to the station, the most simple method is to turn toward the station until the needle is pointing straight up, then make whatever slight turns are necessary to keep the ADF needle pointing straight up. In a no-wind situation, this allows the airplane to navigate in a straight line to the station. In a windy situation, however, where any crosswind exists that will blow the airplane sideways over the ground, keeping the needle at the top of the instrument is called "homing," and will result in a curved path over the ground. Additional techniques are employed to fly a straight line over the ground to the station, involving determining how much drift has taken place, and making a correction for the drift.
Various formulas exist to do this, but I prefer to teach it simply, without a lot of math. If one turns to the station and holds a heading, and finds that the needle drifts to the left a pencil eraser width, one is blowing right of course. One needs to correct back into the wind. The correction at this stage is simple: turn left until the needle is showing two pencil eraser widths from the top, to the right side of the instrument. Hold that until the needle drifts one more eraser width to the right, then turn back to the right one eraser width. This sounds confusing on paper; it's dirt simple in the cockpit. This is how one tracks down the approach when actually flying the approach, and one usually has time enough to make about two corrections before reaching the beacon or runway.
To actually fly the approach, one must generally fly to the beacon, then turn "outbound." This means flying away from the airport or beacon, for a predetermined time or distance. Usually time, and making a distance determination with the beacon alone isn't usually possible. One will time outbound, on a heading opposite the inbound course, for a minute to a minute and a half. One will then make a turn (typically a 45 degree turn, or 60 degree turn, and sometimes a 90 degree turn), and then time for another minute. At that point, one makes a 180 degree turn opposite to the direction one just turned (if one made the 45 degree turn left, then one makes the reversal to the right). One now expects to fly roughly a little less than a minute, depending on wind, to intercept the inbound course. This maneuver is called "course reversal," or the "procedure turn"
It's during the course reversal process that one will begin to configure the airplane for landing, with gear, flaps, etc. One will slow the airplane, and often descend to the altitude from which one will actually begin the approach.
Once one has completed this 180 degree turn, one is headed back at the inbound approach course at a 45 degree angle. (assuming one made one's initial turn at 45 degrees: one was flying outbound, one turned left 45 degrees, and when one turns around the opposite direction, one is flying back to the approach course at a 45 degree angle). Now, one looks for the needle to point to the right 45 degrees, or in other words, half way between straight up, and straight to the right. As soon as this happens, one is over the inbound course, and one turns to the inbound heading.
At this stage, one is established inbound. One needs to consider winds, and apply corrections (as previously described), in order to stay on that course. Flying an NDB approach is more art than science, and it's called a "non-precision approach" because the idea is to land you in the general vicinity of the runway while keeping you clear of obstacles.
The specifics of when to turn, when to let down, and where to commence one's final descent really depend on the nature of the approach. Some approaches have the beacon far from the airfield, and one will let down to the minimum descent altitude (MDA) as soon as one crosses the beacon. In other cases, the beacon may be on the airfield, and one lets down as soon as one has completed one's procedure turn, inbound. The approach plate will spell out the specifics.
I don't know the specific airport procedures to which you're referring, as all my approach plates are electronic, and stay in the airplane. You mentioned Pueblo, but I don't see an NDB procedure for Pueblo (Colorado) or Zuni...perhaps you meant in another country.
Something to bear in mind is that nearly all airplanes these days navigate by GPS. GPS changes the way the information is received, and used in the cockpit. The procedures are still very similar in the way they are flown over the ground, but not the way they are flown in the cockpit. GPS systems generally have moving map displays which allow the pilot a much clearer picture of where he or she is relative to the approach and obstacles, and a much clearer idea of what needs to be done to stay oriented and fly the approach.
Even where NDB's are used (mostly in remote areas, any more), they're often flown as "overlay" approaches, where it's actually GPS that's used to fly the approach, patterned to follow the course and layout of the actually NDB approach. In many cases, the system is so nearly "dumbed down" that the pilot does little more than follow a magenta colored line on the GPS display map. Even in small airplanes without much modern instrumentation, hand-held and portable GPS units that aren't any bigger than the GPS units that are seen in cars these days, are often used. They're typically powered through a cigarette-lighter adapter (DC adapter), with a remote antenna that sticks on the aircraft window with a suction cup. These units still provide a significant amount of situational awareness and information to the pilot, and even in cases where a hand-held unit is used (not legal to use as primary navigation to fly the approach), you'll often find that pilots have the GPS on board anyway, and reference it throughout the procedure.
At the moment I fly the 747, incidentally, and demonstrating an NDB approach, flown on traditional instrumentation, has been a regular part of our training and recurrent training requirements. We still fly into various locations around the world that utilize NDB's, and while our present policies and procedures allow us to fly such an approach as an "overlay" or GPS approach, we are all required to understand and be capable of flying a plain-jane, simple NDB procedure.
As others noted, the beacon requires a power source. A generator works fine, and is often used (NDB's are sometimes only turned on when anticipating a flight, but in other cases are operating all the time.
Flying the NDB approach requires that the pilot monitor the signal from the beacon continuously during the approach. This is especially critical as most cockpit instrumentation in use for flying the NDB wouldn't allow the pilot to know if the beacon failed. Therefore, one must "tune and identify" the station before ever beginning the procedure. This involves setting the proper frequency, then seeing the needle move, then listening for the morse code identifier which is broadcast repeatedly over the station. This identifier, generally two letters in more code, will be left audibly playing until the procedure is complete.
If the beacon were to stop transmitting during the procedure, the needle in the cockpit might not move at all, an the pilot might actually blindly follow the needle without it providing any guidance. By listening to the station and hearing the identifier continuously, the pilot is able to determine that the beacon is still operating, and thus have confidence in following the signals to and from the beacon as received in the cockpit.
This is all a lot more technical than you'll require for your novel, of course. I'd go as simple as possible, and make no assumptions about the reader understanding the material. Perhaps even avoiding terms such as "inbound" or "outbound," or "procedure turn" or "course reversal." Stick with "beacon" and talk about flying away from the beacon or flying back toward it. A course reversal can more simply be described as waiting for the needle to point down, starting one's clock, and flying away from the beacon for a minute. Then turning left, flying for a minute, and turning back around again for another minute. On course, keep the needle at the top of the instrument, correcting for wind, and let down to the minimum altitude, eyes scanning outside and inside.
One has to be flexible when flying the procedure, because the inbound course is seldom actually aligned with the runway. Many NDB approaches require "circling," or turning to get lined up with the runway. If it's less than a 30 degree turn, it's considered a "straight-in" approach, and if it's more, one must "circle", which may involve turning all the way around the airport, at a relatively low altitude, in low visibility, at night, in the weather, to get lined up. If at any point in that process one loses sight of the runway, one must "go missed," or fly the missed approach procedure. This involves a climbing turn toward the runway and following the instructions on the approach chart.
Special considerations if flying to a "tundra strip" at night will be that relatively few features will be discernable on the ground. With few light references, one can become easily "spatially disoriented," or confused about one's reference to "up." One must be especially vigilant on instruments to avoid losing control or flying into the ground. If one is making this approach single pilot, one is performing single pilot instrument work, one of the highest-workload and most challenging things one can do in the cockpit.
Many of the remote airstrips into which I've flown aren't lighted at night, or have poor lighting. Some of them have used flare pots, or burning pots to illuminate the runway edges. Sometimes I've used vehicles at the end of the runway, their headlights pointing in the direction I'm to land, with another (if available) to mark the other end of the strip. In the case of medical operations, usually it's just been the ambulance or truck that's there to move the patient, or the medical crew.
Sometimes the condition of the airfield is questionable. I've landed on airfields which were too muddy with wet clay, dirt and mud, earlier in the day, but which are reported frozen (now with a thick layer of snow on top. In those cases, after flying the approach, I'm running the length of the runway with my wheels on the surface, but just barely, without actually putting the weight of the airplane into the snow or mud. I'll come off, come back around, and fly the length of the runway again, looking to see if mud or water has filled my tracks, before coming around again to actually land.
In other cases, I've had to fly a low pass to check for horses, deer, etc, or to chase people off the runway. If you really want to add some excitement, have the pilot "break out" on the approach, descend to land, and have to go around on his minimum fuel, before making a tight visual turn back to land on fumes. It keeps the reader tense...the approach was tense, and the reader relaxes a little when breaking out and seeing the runway, but you ratchet it up with the go-around, and can eek the last bit of tension out of the scene by having the engine run rough as the pilot turns the nose back onto the final approach to land. Have the engine quit as he or she rolls out, having literally used every last drop to make it. Have the pilot show humanity by shaking uncontrollably in a cold sweat, and leave the reader the same way.
Several thoughts from a fellow writer and pilot:
Unless you're marketing the book to other pilots, then lean toward explaining the event in simple terms. There is no such thing as a "LOM approach." Trying to put that term in your book would be confusing even to a pilot. Instead, a slowly vanishing type of approach is the NDB Approach ("non-directional beacon"), which involves a beacon, often in remote areas. The beacon is simply an AM radio station, and uses an instrument that points to the station. Some instruments are integrated with compass features, to show the airplane heading all the time, and thus make orientation to the station a little easier. These instruments are called "RMI's" (radio magnetic indicators). Other systems use a "fixed card ADF" instrument, which is nothing more than a needle which points to the position of the beacon.
When a pilot intends to fly the approach, generally one flies the airplane directly to the beacon itself. In the cockpit, the indication is a needle which turns on a circular dial instrument. If the needle points up, then the beacon is in front of the airplane. If the needle points down, the beacon is behind the airplane. If the needle is directly to the right, the beacon is off the right wing, or in other words, 90 degrees to the heading of the airplane. If the needle points to the left, that puts the beacon 90 degrees to the right of the airplane, with a relative bearing of 270 degrees.
Another way of thinking about the NDB and staying oriented to it is to think of the instrument in the cockpit as showing the direction, relative to the front of the airplane, of the beacon. The "o'clock" position, if you will. Behind would be the six o'clock position, to the left would be the nine o'clock position, etc.
If one is to fly a particular bearing to the station, a specific course over the ground, one needs to be able to orient one's self using the cockpit instrumentation by determining one's heading and bearing on the RMI/ADF, and then timing the rate at which the needle moves to determine how far from the station one is. This gives one the information necessary to determine position (bearing and distance), and thus where to go to get on the necessary course.
If one wishes to fly to the station, the most simple method is to turn toward the station until the needle is pointing straight up, then make whatever slight turns are necessary to keep the ADF needle pointing straight up. In a no-wind situation, this allows the airplane to navigate in a straight line to the station. In a windy situation, however, where any crosswind exists that will blow the airplane sideways over the ground, keeping the needle at the top of the instrument is called "homing," and will result in a curved path over the ground. Additional techniques are employed to fly a straight line over the ground to the station, involving determining how much drift has taken place, and making a correction for the drift.
Various formulas exist to do this, but I prefer to teach it simply, without a lot of math. If one turns to the station and holds a heading, and finds that the needle drifts to the left a pencil eraser width, one is blowing right of course. One needs to correct back into the wind. The correction at this stage is simple: turn left until the needle is showing two pencil eraser widths from the top, to the right side of the instrument. Hold that until the needle drifts one more eraser width to the right, then turn back to the right one eraser width. This sounds confusing on paper; it's dirt simple in the cockpit. This is how one tracks down the approach when actually flying the approach, and one usually has time enough to make about two corrections before reaching the beacon or runway.
To actually fly the approach, one must generally fly to the beacon, then turn "outbound." This means flying away from the airport or beacon, for a predetermined time or distance. Usually time, and making a distance determination with the beacon alone isn't usually possible. One will time outbound, on a heading opposite the inbound course, for a minute to a minute and a half. One will then make a turn (typically a 45 degree turn, or 60 degree turn, and sometimes a 90 degree turn), and then time for another minute. At that point, one makes a 180 degree turn opposite to the direction one just turned (if one made the 45 degree turn left, then one makes the reversal to the right). One now expects to fly roughly a little less than a minute, depending on wind, to intercept the inbound course. This maneuver is called "course reversal," or the "procedure turn"
It's during the course reversal process that one will begin to configure the airplane for landing, with gear, flaps, etc. One will slow the airplane, and often descend to the altitude from which one will actually begin the approach.
Once one has completed this 180 degree turn, one is headed back at the inbound approach course at a 45 degree angle. (assuming one made one's initial turn at 45 degrees: one was flying outbound, one turned left 45 degrees, and when one turns around the opposite direction, one is flying back to the approach course at a 45 degree angle). Now, one looks for the needle to point to the right 45 degrees, or in other words, half way between straight up, and straight to the right. As soon as this happens, one is over the inbound course, and one turns to the inbound heading.
At this stage, one is established inbound. One needs to consider winds, and apply corrections (as previously described), in order to stay on that course. Flying an NDB approach is more art than science, and it's called a "non-precision approach" because the idea is to land you in the general vicinity of the runway while keeping you clear of obstacles.
The specifics of when to turn, when to let down, and where to commence one's final descent really depend on the nature of the approach. Some approaches have the beacon far from the airfield, and one will let down to the minimum descent altitude (MDA) as soon as one crosses the beacon. In other cases, the beacon may be on the airfield, and one lets down as soon as one has completed one's procedure turn, inbound. The approach plate will spell out the specifics.
I don't know the specific airport procedures to which you're referring, as all my approach plates are electronic, and stay in the airplane. You mentioned Pueblo, but I don't see an NDB procedure for Pueblo (Colorado) or Zuni...perhaps you meant in another country.
Something to bear in mind is that nearly all airplanes these days navigate by GPS. GPS changes the way the information is received, and used in the cockpit. The procedures are still very similar in the way they are flown over the ground, but not the way they are flown in the cockpit. GPS systems generally have moving map displays which allow the pilot a much clearer picture of where he or she is relative to the approach and obstacles, and a much clearer idea of what needs to be done to stay oriented and fly the approach.
Even where NDB's are used (mostly in remote areas, any more), they're often flown as "overlay" approaches, where it's actually GPS that's used to fly the approach, patterned to follow the course and layout of the actually NDB approach. In many cases, the system is so nearly "dumbed down" that the pilot does little more than follow a magenta colored line on the GPS display map. Even in small airplanes without much modern instrumentation, hand-held and portable GPS units that aren't any bigger than the GPS units that are seen in cars these days, are often used. They're typically powered through a cigarette-lighter adapter (DC adapter), with a remote antenna that sticks on the aircraft window with a suction cup. These units still provide a significant amount of situational awareness and information to the pilot, and even in cases where a hand-held unit is used (not legal to use as primary navigation to fly the approach), you'll often find that pilots have the GPS on board anyway, and reference it throughout the procedure.
At the moment I fly the 747, incidentally, and demonstrating an NDB approach, flown on traditional instrumentation, has been a regular part of our training and recurrent training requirements. We still fly into various locations around the world that utilize NDB's, and while our present policies and procedures allow us to fly such an approach as an "overlay" or GPS approach, we are all required to understand and be capable of flying a plain-jane, simple NDB procedure.
As others noted, the beacon requires a power source. A generator works fine, and is often used (NDB's are sometimes only turned on when anticipating a flight, but in other cases are operating all the time.
Flying the NDB approach requires that the pilot monitor the signal from the beacon continuously during the approach. This is especially critical as most cockpit instrumentation in use for flying the NDB wouldn't allow the pilot to know if the beacon failed. Therefore, one must "tune and identify" the station before ever beginning the procedure. This involves setting the proper frequency, then seeing the needle move, then listening for the morse code identifier which is broadcast repeatedly over the station. This identifier, generally two letters in more code, will be left audibly playing until the procedure is complete.
If the beacon were to stop transmitting during the procedure, the needle in the cockpit might not move at all, an the pilot might actually blindly follow the needle without it providing any guidance. By listening to the station and hearing the identifier continuously, the pilot is able to determine that the beacon is still operating, and thus have confidence in following the signals to and from the beacon as received in the cockpit.
This is all a lot more technical than you'll require for your novel, of course. I'd go as simple as possible, and make no assumptions about the reader understanding the material. Perhaps even avoiding terms such as "inbound" or "outbound," or "procedure turn" or "course reversal." Stick with "beacon" and talk about flying away from the beacon or flying back toward it. A course reversal can more simply be described as waiting for the needle to point down, starting one's clock, and flying away from the beacon for a minute. Then turning left, flying for a minute, and turning back around again for another minute. On course, keep the needle at the top of the instrument, correcting for wind, and let down to the minimum altitude, eyes scanning outside and inside.
One has to be flexible when flying the procedure, because the inbound course is seldom actually aligned with the runway. Many NDB approaches require "circling," or turning to get lined up with the runway. If it's less than a 30 degree turn, it's considered a "straight-in" approach, and if it's more, one must "circle", which may involve turning all the way around the airport, at a relatively low altitude, in low visibility, at night, in the weather, to get lined up. If at any point in that process one loses sight of the runway, one must "go missed," or fly the missed approach procedure. This involves a climbing turn toward the runway and following the instructions on the approach chart.
Special considerations if flying to a "tundra strip" at night will be that relatively few features will be discernable on the ground. With few light references, one can become easily "spatially disoriented," or confused about one's reference to "up." One must be especially vigilant on instruments to avoid losing control or flying into the ground. If one is making this approach single pilot, one is performing single pilot instrument work, one of the highest-workload and most challenging things one can do in the cockpit.
Many of the remote airstrips into which I've flown aren't lighted at night, or have poor lighting. Some of them have used flare pots, or burning pots to illuminate the runway edges. Sometimes I've used vehicles at the end of the runway, their headlights pointing in the direction I'm to land, with another (if available) to mark the other end of the strip. In the case of medical operations, usually it's just been the ambulance or truck that's there to move the patient, or the medical crew.
Sometimes the condition of the airfield is questionable. I've landed on airfields which were too muddy with wet clay, dirt and mud, earlier in the day, but which are reported frozen (now with a thick layer of snow on top. In those cases, after flying the approach, I'm running the length of the runway with my wheels on the surface, but just barely, without actually putting the weight of the airplane into the snow or mud. I'll come off, come back around, and fly the length of the runway again, looking to see if mud or water has filled my tracks, before coming around again to actually land.
In other cases, I've had to fly a low pass to check for horses, deer, etc, or to chase people off the runway. If you really want to add some excitement, have the pilot "break out" on the approach, descend to land, and have to go around on his minimum fuel, before making a tight visual turn back to land on fumes. It keeps the reader tense...the approach was tense, and the reader relaxes a little when breaking out and seeing the runway, but you ratchet it up with the go-around, and can eek the last bit of tension out of the scene by having the engine run rough as the pilot turns the nose back onto the final approach to land. Have the engine quit as he or she rolls out, having literally used every last drop to make it. Have the pilot show humanity by shaking uncontrollably in a cold sweat, and leave the reader the same way.
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Wow, thanks for the answers, everyone (especially SNS3Guppy, the 747 pilot). You have all been very helpful with lots of information. 
And yes, I already know to put it in simple terms for the novel -- I just want to make sure that all the facts check out so that it won't be an ill-researched mess like the last Airport movie with the Concorde (if you've ever seen it, it's a perfect example of how NOT to make an aviation-themed disaster movie, unlike the original Airport movie which was excellent). As for my question, I see that I wasn't clear about it, so I think I'll have to provide more details about the situation: the plane in question is approaching Coral Harbor (which is way up there in the Nunavut, just south of the Arctic Circle) on a heading of 315; the active runway at the time is Runway 34; and the "LOM" in question is NOT technically an LOM associated with an ILS that happens to be out of service (in fact, there's no ILS installed there at all), but an NDB that is on the extended runway centerline (more or less) near the approach end of Runway 34, in a position similar to where the LOM would have been if it was part of an ILS system. And for the record, the plane in question is a Queen Air and doesn't have GPS. In this type of approach, it's pretty clear that a course reversal is not called for because then the plane would end up going in the opposite direction from that used for landing. So my question is, would it be acceptable in this case to fly straight in, or would my heroine have to fly around the traffic pattern once in order to refine the approach? (Remember, the beacon is off the approach end in this case.) As the scene stands right now, I have her fly one full circuit of the traffic pattern, using the NDB for guidance and a timed upwind leg, before making the final approach; is this considered an acceptable procedure? That's what I'd like to know.
Oh, and SNS3Guppy -- thanks for the tip about the runway surface, I think I'll make it very muddy to complicate things, and maybe have a strong gust of wind throw the plane out of balance at the last minute.
And yes, I already know to put it in simple terms for the novel -- I just want to make sure that all the facts check out so that it won't be an ill-researched mess like the last Airport movie with the Concorde (if you've ever seen it, it's a perfect example of how NOT to make an aviation-themed disaster movie, unlike the original Airport movie which was excellent). As for my question, I see that I wasn't clear about it, so I think I'll have to provide more details about the situation: the plane in question is approaching Coral Harbor (which is way up there in the Nunavut, just south of the Arctic Circle) on a heading of 315; the active runway at the time is Runway 34; and the "LOM" in question is NOT technically an LOM associated with an ILS that happens to be out of service (in fact, there's no ILS installed there at all), but an NDB that is on the extended runway centerline (more or less) near the approach end of Runway 34, in a position similar to where the LOM would have been if it was part of an ILS system. And for the record, the plane in question is a Queen Air and doesn't have GPS. In this type of approach, it's pretty clear that a course reversal is not called for because then the plane would end up going in the opposite direction from that used for landing. So my question is, would it be acceptable in this case to fly straight in, or would my heroine have to fly around the traffic pattern once in order to refine the approach? (Remember, the beacon is off the approach end in this case.) As the scene stands right now, I have her fly one full circuit of the traffic pattern, using the NDB for guidance and a timed upwind leg, before making the final approach; is this considered an acceptable procedure? That's what I'd like to know.Oh, and SNS3Guppy -- thanks for the tip about the runway surface, I think I'll make it very muddy to complicate things, and maybe have a strong gust of wind throw the plane out of balance at the last minute.
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AgentOrange,
A course reversal is always required unless given vectors by ATC or the chart is published with a statement that the course reversal is not required. A procedure turn (course reversal) is a required maneuver. Yes, it does involve going the opposite direction from the runway, but the purpose of the procedure turn is to get established; configured, stable, and on the appropriate altitude and airspeed.
One flies to the NDB, and tracks outbound for one minute, then does the procedure turn before tracking inbound. Generally one will hold the inbound altitude until crossing the NDB,then reduce power and descend to the minimum approach altitude.
If you have a link to the specific procedure, it will be easier to address, but terrain and obstacle clearance in the procedure is predicated on flying to the beacon first, and then executing a procedure turn as part of the maneuver. If you're looking at the approach chart, you should see the depiction of the procedure in a smaller box under the main big box, shown from the side, or "plan view." There should be a line from the beacon leading downward to the minimum altitude, and then somewhere in there the runway. On the other side of the beacon, there should be a minimum altitude specified, and a note that says something along the lines of "remain within 10 nm." This distance, the ten nautical miles, is the distance within which one must remain while flying the procedure turn, and the altitude shown is the minimum altitude at which the procedure turn may be flown (specifically, the minimum inbound altitude, once established; the turn may be flown higher).
The procedure turn is a way of getting the airplane fully established before it crosses the NDB. It's also the time that the pilot will make his initial crosswind correction. It's easier to do with the needle pointing up, than down. With an NDB approach, one wants to get established early, and stay established, because otherwise one simply goes hunting back and fourth across the bearing to the airport.
Does this procedure depict a traffic pattern that crosses the beacon? I haven't seen any like that in Canada, though I've seen them frequently in Russia. Generally, there's no traffic pattern in the procedure, save for any circling maneuvering that might be required when one "breaks out" of the cloud during the approach.
You appear to be describing a situation in which a pilot flies a downwind leg parallel to the runway, then a base (at a right angle to the runway), then turns final approach over the beacon. While there are some procedures like that in Russia, US and Canadian NDB approaches nearly always have the pilot go directly to the beacon, then fly outbound (opposite the runway, in this case), to execute the procedure turn.
Of curiosity, is the procedure to which you refer entitled a "LOM" approach? Generally speaking, one can't have an LOM if one doesn't have an ILS or localizer. The procedure will normally be labeled as an NDB (or NDB/GPS) approach.
Just to be clear, you're talking about this procedure being flown on instruments, correct? If it's a visual approach to land, then the procedure may be irrelevant.
A course reversal is always required unless given vectors by ATC or the chart is published with a statement that the course reversal is not required. A procedure turn (course reversal) is a required maneuver. Yes, it does involve going the opposite direction from the runway, but the purpose of the procedure turn is to get established; configured, stable, and on the appropriate altitude and airspeed.
One flies to the NDB, and tracks outbound for one minute, then does the procedure turn before tracking inbound. Generally one will hold the inbound altitude until crossing the NDB,then reduce power and descend to the minimum approach altitude.
If you have a link to the specific procedure, it will be easier to address, but terrain and obstacle clearance in the procedure is predicated on flying to the beacon first, and then executing a procedure turn as part of the maneuver. If you're looking at the approach chart, you should see the depiction of the procedure in a smaller box under the main big box, shown from the side, or "plan view." There should be a line from the beacon leading downward to the minimum altitude, and then somewhere in there the runway. On the other side of the beacon, there should be a minimum altitude specified, and a note that says something along the lines of "remain within 10 nm." This distance, the ten nautical miles, is the distance within which one must remain while flying the procedure turn, and the altitude shown is the minimum altitude at which the procedure turn may be flown (specifically, the minimum inbound altitude, once established; the turn may be flown higher).
The procedure turn is a way of getting the airplane fully established before it crosses the NDB. It's also the time that the pilot will make his initial crosswind correction. It's easier to do with the needle pointing up, than down. With an NDB approach, one wants to get established early, and stay established, because otherwise one simply goes hunting back and fourth across the bearing to the airport.
Does this procedure depict a traffic pattern that crosses the beacon? I haven't seen any like that in Canada, though I've seen them frequently in Russia. Generally, there's no traffic pattern in the procedure, save for any circling maneuvering that might be required when one "breaks out" of the cloud during the approach.
You appear to be describing a situation in which a pilot flies a downwind leg parallel to the runway, then a base (at a right angle to the runway), then turns final approach over the beacon. While there are some procedures like that in Russia, US and Canadian NDB approaches nearly always have the pilot go directly to the beacon, then fly outbound (opposite the runway, in this case), to execute the procedure turn.
Of curiosity, is the procedure to which you refer entitled a "LOM" approach? Generally speaking, one can't have an LOM if one doesn't have an ILS or localizer. The procedure will normally be labeled as an NDB (or NDB/GPS) approach.
Just to be clear, you're talking about this procedure being flown on instruments, correct? If it's a visual approach to land, then the procedure may be irrelevant.
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A153O - I think you are tying yourself up in knots here. If the NDB is 'near the approach end of R34' it would not be in the same place as an ILS LOM. It would be a simple NDB at the threshold. How does this QueenAir KNOW it is approaching the airfield ie how is it determining its distance from the field?? With only an NDB, the ONLY way, without other aids like radar, DME or GPS to make such an approach, is to carry out the course reversal we have described (or, of course, fly the complicated eastern bloc 'rectangle' you describe). Having completed whichever reversal procedure is appropriate the aircraft could then descend to the minimum approach altitude knowing it is within a certain distance from the field.
How about just write in a reversal and be done with it?
How about just write in a reversal and be done with it?
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hi
I think it's an NDB which also serves as the ILS outer marker.
you cant think you have know.IS that the runway i think so OK land. were did all the cars come from?
cheers chris
you cant think you have know.IS that the runway i think so OK land. were did all the cars come from?
cheers chris
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Thank you Guppy and BOAC, you have answered my question. So from what you said, a straight-in approach is not acceptable except where expressly specified (which sounds reasonable); and the rectangle, which I initially chose because it makes for a "360-degree course reversal", so to speak, and puts the plane back on the same heading it was flying before, is used only in Eastern Europe and the USSWere. So this leaves me with having my heroine do two 180-degree course reversals back-to-back. More's the pity. 
Now as for the two types of procedure turns used for the course reversal: I don't like the barb-type procedure turn because of the distance that has to be covered (and if you were coming in as bingo-fuel as my heroine
, I'm sure you wouldn't like it either). The teardrop, on the other hand, is a nice compact procedure turn, and AFAIK actually uses less fuel than the rectangle. 
So what I think I'll do is either put two 30/210-degree teardrops back-to-back to make a sort of "bowtie" or "figure-eight", or make a 1-minute 45/180 barb one way and a 30/210 teardrop the other way. Any thoughts on that?
Now as for the two types of procedure turns used for the course reversal: I don't like the barb-type procedure turn because of the distance that has to be covered (and if you were coming in as bingo-fuel as my heroine
, I'm sure you wouldn't like it either). The teardrop, on the other hand, is a nice compact procedure turn, and AFAIK actually uses less fuel than the rectangle. So what I think I'll do is either put two 30/210-degree teardrops back-to-back to make a sort of "bowtie" or "figure-eight", or make a 1-minute 45/180 barb one way and a 30/210 teardrop the other way. Any thoughts on that?
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Of curiosity, is the procedure to which you refer entitled a "LOM" approach? Generally speaking, one can't have an LOM if one doesn't have an ILS or localizer. The procedure will normally be labeled as an NDB (or NDB/GPS) approach.
Just to be clear, you're talking about this procedure being flown on instruments, correct? If it's a visual approach to land, then the procedure may be irrelevant.
Just to be clear, you're talking about this procedure being flown on instruments, correct? If it's a visual approach to land, then the procedure may be irrelevant.
As for whether the procedure is being flown on instruments: Yes, of course! Where would all the suspense be if Heather (that's my heroine's name, BTW) could fly the approach visually? As a matter of fact, she's flying the approach in the daytime, but with a solid overcast only 500 feet above the field, visibility at runway level being 1 mile in a pouring rain, and with a 20-knot crosswind gusting to 27 to boot, as well as severe icing between 4000 and 7000 feet. Sounds like real fun, doesn't it?
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Any thoughts on that?
I don't think there is a significant increase in track mileage between the two reversals.
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ow as for the two types of procedure turns used for the course reversal: I don't like the barb-type procedure turn because of the distance that has to be covered (and if you were coming in as bingo-fuel as my heroine, I'm sure you wouldn't like it either). The teardrop, on the other hand, is a nice compact procedure turn, and AFAIK actually uses less fuel than the rectangle. So what I think I'll do is either put two 30/210-degree teardrops back-to-back to make a sort of "bowtie" or "figure-eight", or make a 1-minute 45/180 barb one way and a 30/210 teardrop the other way. Any thoughts on that?
When a barb is shown, any kind of turn may be made. You won't save fuel doing one or the other.
I'm confused about all the reversals. You may be making it a lot more complicated than necessary.
1. Fly to the beacon.
2. Fly outbound.
3. Turn around and fly inbound.
4. Land.
It's that simple. Fly to the beacon, and turn outbound. Track the bearing outbound for one minute. If the barb is on the left side of the course, then turn 45 degrees left. Fly for a minute. Now turn right 180 degrees. Fly until intercepting the inbound course, and then turn inbound. Fly to the beacon. Descend to the minimum descent altitude. Begin timing, or whatever method is prescribed for locating the missed approach point. Either see the runway and land, or fly the missed approach procedure specified on the chart.
There really aren't two 180 degree reversals or turns. One flies outbound, then turns around and flies inbound. That's the reversal. It should take five minutes, more or less. Figure five minutes of fuel consumption, though fuel consumption does go up a little as one is configured for landing with gear and flaps out for the latter part of the procedure turn.
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SN3 - you have missed his/her point - 'Heather' is approaching in the landing direction. therefore two reversals. I don't think you would pass an IRT your way!