NDB approach flapless scenario
PPRuNeaholic
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Changing to a high category, as has been suggested, is unlikely to be helpful because the procedure is speed limited to 180 knots for initial approach. You are, however, in a very serious situation in this unlikely scenario and should be able to remain within the protection area of the procedure, due to the conservative limits applied. Pans Ops allows use of a "statistical wind" or, if that isn't available to the designer, the formula is 2h+47, where h=height in thousands of feet.
Therefore, if the "h" factor is 2000 then the value is 2*2+47 = 51 knots. You probably won't know the height factor that has been used and, indeed, might be subject to the "statistical wind", which might actually be less. This will be the factor that limits the size of the primary protection area, but there is still a secondary area of 2.5 NM outside the primary area. Obstacle clearance reduces to 0 at the outer edge of this area, but it's unlikely that a 50 or 60 knot wind will displace you that far in the time it takes to complete the turn to the inbound track.
You will have to fly very precisely and probably use a bank angle steeper than the design angle of 25 degrees to remain within the protection area. This will lead to the next problem - the time (and therefore distance) needed to bring the aeroplane within the tracking tolerance for final approach - usually + or - 5 degrees - before continuing descent to the MDA. You might not have enough time/distance to reach the MDA unless you can accept a higher ROD than usual.
So, yes, it'd be a pretty serious situation but I'd have to say that, pending any factual information to the contrary, there hasn't been any incident of this kind, so the chances of it actually happening are really pretty remote. But I guess that's why Captains are paid such big money!
Therefore, if the "h" factor is 2000 then the value is 2*2+47 = 51 knots. You probably won't know the height factor that has been used and, indeed, might be subject to the "statistical wind", which might actually be less. This will be the factor that limits the size of the primary protection area, but there is still a secondary area of 2.5 NM outside the primary area. Obstacle clearance reduces to 0 at the outer edge of this area, but it's unlikely that a 50 or 60 knot wind will displace you that far in the time it takes to complete the turn to the inbound track.
You will have to fly very precisely and probably use a bank angle steeper than the design angle of 25 degrees to remain within the protection area. This will lead to the next problem - the time (and therefore distance) needed to bring the aeroplane within the tracking tolerance for final approach - usually + or - 5 degrees - before continuing descent to the MDA. You might not have enough time/distance to reach the MDA unless you can accept a higher ROD than usual.
So, yes, it'd be a pretty serious situation but I'd have to say that, pending any factual information to the contrary, there hasn't been any incident of this kind, so the chances of it actually happening are really pretty remote. But I guess that's why Captains are paid such big money!
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You could fly the procedure at a lower IAS (ie 185kts) which may be below your min clean speed. but
Minimum Recommended Manoeuvring Speeds:
• Allows an inadvertent 15° overshoot beyond the normal 25° bank angle.
• Provides more than a 1.3 “g” margin over stick shaker speed.
• Is valid for all weights up to the maximum structural take-off weight.
GEN 1.7 — DIFFERENCES FROM ICAO STANDARDS, RECOMMENDED PRACTICES AND PROCEDURES
UK AIP (12 Feb 09) GEN 1-7-51
UK Adition Procedure speed restrictions.
Unless otherwise stated, procedures are speed restricted to a maximum IAS of 185 kt
Minimum Recommended Manoeuvring Speeds:
• Allows an inadvertent 15° overshoot beyond the normal 25° bank angle.
• Provides more than a 1.3 “g” margin over stick shaker speed.
• Is valid for all weights up to the maximum structural take-off weight.
GEN 1.7 — DIFFERENCES FROM ICAO STANDARDS, RECOMMENDED PRACTICES AND PROCEDURES
UK AIP (12 Feb 09) GEN 1-7-51
UK Adition Procedure speed restrictions.
Unless otherwise stated, procedures are speed restricted to a maximum IAS of 185 kt
Last edited by JAR; 16th Aug 2009 at 09:49.
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The scenario leads to some questions about the normal operation of the aircraft at this aerodrome.
If the plan was to fly the NDB timed procedure and the ountobund leg is limited to 180Knots then why was the aircraft not at 180 knots (and configured) prior to starting the leg?
Not only does it appear the aircraft proceed outbound on the procedure in excess of the maximum speed but the plan of reducing speed and configuring the aircraft while outbound plays havock with the timing does it not?
Therefore my biggest question is why was the flap problem not discovered prior to proceeding outbound?
That would at a minimum have permitted 1 or two more holds while speeds were re-calculated etc etc. What you have not even thought about is the missed approach - even if there is fuel left, can you comply with the missed approach speed requirements? No point in rushing the procedure and keeping some fuel for a missed approach that you can't fly.
If as per the scenario, the only option is to complete the outbound at 205 knots rather than the planned 180 then I would count that has having an effective tailwind of 25 knots (in no wind conditions) and adjust the timing accordingly.
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It would be some emergency if the aircraft ATC puts ahead blocks the runway. 
Let me see, I am over a the only field that i can land at because I have no fuel to divert and I have a flap problem. I may not be able to execute a missed approach as published and the landing could result in an over-run
Unless I had enough fuel to hold while a disabled aircraft was removed then I want to own that runway and if necessary others are going to have to wait / divert. The words "Mayday" will give ATC a clear indication of why I am demanding that.
If the plan was to fly the NDB timed procedure and the ountobund leg is limited to 180Knots then why was the aircraft not at 180 knots (and configured) prior to starting the leg?
Not only does it appear the aircraft proceed outbound on the procedure in excess of the maximum speed but the plan of reducing speed and configuring the aircraft while outbound plays havock with the timing does it not?
Therefore my biggest question is why was the flap problem not discovered prior to proceeding outbound?
That would at a minimum have permitted 1 or two more holds while speeds were re-calculated etc etc. What you have not even thought about is the missed approach - even if there is fuel left, can you comply with the missed approach speed requirements? No point in rushing the procedure and keeping some fuel for a missed approach that you can't fly.
If as per the scenario, the only option is to complete the outbound at 205 knots rather than the planned 180 then I would count that has having an effective tailwind of 25 knots (in no wind conditions) and adjust the timing accordingly.
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Originally Posted by 411A
Get a grip, Shaunny, it's not an emergency...it's an abnormal.
Let me see, I am over a the only field that i can land at because I have no fuel to divert and I have a flap problem. I may not be able to execute a missed approach as published and the landing could result in an over-run
Unless I had enough fuel to hold while a disabled aircraft was removed then I want to own that runway and if necessary others are going to have to wait / divert. The words "Mayday" will give ATC a clear indication of why I am demanding that.
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A training captain once uttered the following words to me, and they have stuck ever since - "...once that happens, all bets are off"
In your situation, you have already diverted and fuel is tight - the approach you briefed has just gone out the window.
Still have time? Get PNF to check the perf and adjust (bodge...) the timing, ROD and outbound track (terrain permitting).
If you pull it all together, you should be in a good position to make a visual at or before minimums. If you really are tight on fuel, you might have to keep it going with the RA as a reference to terrain. [I know how crazy that sounds - but remember, if its that bad "all bets are off".
The only thing guaranteed, you are coming down! One way or the other
In your situation, you have already diverted and fuel is tight - the approach you briefed has just gone out the window.
Still have time? Get PNF to check the perf and adjust (bodge...) the timing, ROD and outbound track (terrain permitting).
If you pull it all together, you should be in a good position to make a visual at or before minimums. If you really are tight on fuel, you might have to keep it going with the RA as a reference to terrain. [I know how crazy that sounds - but remember, if its that bad "all bets are off".
The only thing guaranteed, you are coming down! One way or the other
