NDB approach flapless scenario

[abc1]

How would you fly this approach?
NDB approach in imc, no DME, timed only, max speed 180kts for initial,non normal develops into flapless(you find this out once you are outbound)flaps stuck between 0-1, aircraft B737NG, clean speed 205kts.
Non enough fuel to divert as you have diverted already. High terrain either side of approach corridor especially outbound.
Your thoughts please chaps.

[Capt Pit Bull]

where the wind coming from?

[BOAC]

.....and lift your feet off the floor as you go over the hills just in case:) Actually seriously there is nothing to stop you reducing below 205 with the built-in margins. Did you have any Leds?

[abc1]

Wind on landing, 30'deg of centerline at 20 kts.
Ridiculous I agree but if only this thought can be shared with the examiner.
Can you/would you adjust timing to that for a higher category aircraft(I know in a normal situation it is not allowed)however the higher category aircraft will have a different /extended area of operation?

[oceancrosser]

Well if you are stuck with higher speeds and there is a higher category profile existing, I would absolutely go with that one.

[Akrapovic]

Not enough fuel to divert, but how much remaining?? - I certainly wouldn't want to rush into a non-normal approach and landing without having 'run the checklist' and briefed everyone concerned.
Landing distance available, Wet/Dry runway, Affected systems, Missed approach considerations, Cabin Crew / ATC / Flight deck (re) brief.
Could you do all that while outbound, flying/monitoring the approach?

[Capn Bloggs]

I concur with a good brief: go around (fuel permitting), brief, then redo the approach. Go outbound on the wide side, within your tracking allowance (5° here), then if needed you can go 5° wide on the inbound turn until you get established and get back over onto track.

[SNS3Guppy]

Can you/would you adjust timing to that for a higher category aircraft(I know in a normal situation it is not allowed)however the higher category aircraft will have a different /extended area of operation?


Of course you're going to time for the approach category in which you're operating. Whether you're another approach category or not is irrelevant: use the numbers appropriate to the speed at which you're flying. Use the higher minimums, and the appropriate times.

Where is using the next highest category minimums not allowed? All you're doing is being more conservative, and in this case it's a necessity, because you're flying the approach faster.

With this in mind, do you know your landing performance flaps-up, and given the limitations already imposed, do you still have adequate runway?

[Capt Pit Bull]

Wind on landing, 30'deg of centerline at 20 kts

When I asked what the wind was doing, I meant aloft. Its pretty key really.

Your radius of turn relates to V^2, so flying 205 instead of 180 is going to tend to put you through the centreline, but as long as you track accuratley outbound and maintain your bank angle around the turn you'd probably be only slightly through and it would be correctable.

If you had say 30 knots blowing across the pattern, (i.e. tightening your turn) you'd be golden.

But if you had 30 knots the otherway, you'd be really struggling, and some sort of compromise of outbound tracking / speed / bank angle would be needed.

Its all about crosswind really.

pb

[411A]

First we have this...

... normal develops into flapless(you find this out once you are outbound)flaps stuck

then, this...Non enough fuel to divert as you have diverted already....

So, we have what might be called a not too favorable situation.

Then, we have had this suggested...
I certainly wouldn't want to rush into a non-normal approach and landing without having 'run the checklist' and briefed everyone concerned.
Landing distance available, Wet/Dry runway, Affected systems, Missed approach considerations, Cabin Crew / ATC / Flight deck (re) brief

IF fuel is really critical, no amount of 'briefing' is going to do much good.
Not time for committee meetings ....time for considered action on the part of the Commander.

Could you do all that while outbound, flying/monitoring the approach?

In a really critical situation (IE: very low fuel), I would suggest that if one cannot, the pointy end is not the place to be...especially for a Commander.

[galaxy flyer]

Reminds me of someone who proposed a similar scenario to an ancient sea captain in the Age of Sail. His answer: I would not have allowed the situation to get that bad.

GF

[bookworm]

Where is using the next highest category minimums not allowed? All you're doing is being more conservative, and in this case it's a necessity, because you're flying the approach faster.

Using the timing and tracks (which is what abc1 was referring to rather than minimums, I think) for a higher speed category is potentially an issue because of the greater effect of wind on an aircraft at a lower speed than intended by the procedure design. But if you're actually flying the approach faster, then of course you must use the procedure (timning, tracks and minimums) appropriate to the speed actually flown.

[bucket_and_spade]

Reminds me of someone who proposed a similar scenario to an ancient sea captain in the Age of Sail. His answer: I would not have allowed the situation to get that bad.Agreed! But, assuming you'd got yourself in to that Godforsaken place...

Go-around (you should have enough fuel for the full procedural missed approach - the skipper could modify the published if needs be to reduce burn) and put in as much prep/thought as you can until it becomes critical to start the approach (fuel-wise)?

Running the checks may well get the flaps/slats moving to where they should be, allowing a normal config for the approach.

[Akrapovic]

IF fuel is really critical, no amount of 'briefing' is going to do much good.

Not having enough fuel to divert might not necessarily mean you're on vapours - theoretically you might have a couple of hours endurance left in the tank. I appreciate what you're saying but so don't be so fast to shoot down the idea of briefing. This example is useless unless we're given more facts.

[ReverseFlight]

Of course you'd have to make allowances for speed and if unable to slow down maybe cut the time outbound a little bit and try and progressively reduce the intercept to the inbound in the circumstances.

If I were PIC, I'd declare an emergency right away so that Tower can clear the runway or vector you for a safe approach as appropriate. Strange nobody has thought of this - are you on FlightSim ?

[Shaunny]

I think it goes with out saying that you would declare an emergency...

Maybe its different in other parts of the world but where I fly if im doing a procedural NDB approach that usually means they aint gonna be able to vector me anywhere :sad:

As mentioned earlier though without more infomation we're just speculating!

[Mach E Avelli]

I disagree that this is an unlikely scenario, as I have experienced it twice in my career; albeit without the NDB approach speed being limiting.
If you have no fuel and you are at a destination where the flaps fail, you have no choice but to carry out the best approach available to the best runway available. If that's an NDB to circle to some short strip covered in water, so be it. If you are some place that requires an NDB approach, of course the runway will be wet and it won't be grooved.
The regulations don't require you to consider flapless performance; the emergency you need to consider for planning purposes is one-engine-inoperative capability for the entire route including landing and/or missed approach.
So, keep it simple. Depending on the approach design, terrain etc, either reduce timing outbound or knock 25 knots off the recommended clean speed and restrict bank angle to 15 degrees, or do both if it is really restrictive in terms of turning radius. It won't stall unless you do something really stupid like pull 'g' while turning. Ditto if the runway is too short for a flapless landing. In the scenario, you don't have the luxury to divert so you ARE going to land. So, if the runway is less than required, kiss goodbye to the wind/gust additives to flapless Vref and fly very accurately. Dumping it on the numbers and apply aggressive braking, reverse etc will get it stopped within the confines of the runway.
Manoeuvering speeds are very conservative. Compare V2 for any flap configuration with Vman for the same flap e.g. B737 flap 1 V2 could be 155 knots at your weight but Vman typically 190, so that says you can safely pull 15 degrees of bank at 155 knots whether taking off OR approaching in that flap configuration.
Every ops manual and every state regulatory body either does state, or should state, that the Captain can step outside the rules, AFM , SOP or whatever else if necessary to save the ship.

[fat'n'grey]

The tolerances built in to NDB and VOR approaches, both for width of the track overhead the facility, the angle it splays out, for track error and timing, pilot reaction times, acft reaction time, an omni-directional wind allowance etc, are pretty big. You would be surprised. Have a look at ICAO PANS-OPS doc 8168.

For me, fly as close as possible to acft/procedure limiting speeds, adjust timing, expect that you may fly through the final app course and regain it asap.

So easy to say from the comfort of a chair and hindsight. Not nice on the day with no notice however!

Oh dear!

[Mach E Avelli]

Good point about the approach design tolerances because they have to allow for a certain wind strength (I forget what it is but one authority used to apply 60 knots in the most adverse direction to any procedure that was time-based only). If the wind is 60 knots it is NOT your day!
However, a snippy sim examiner may have a go at you if you deliberately exceed a published limit. But of course you are allowed plus 10 knots on any speed, so technically he could not fail you for flying at 190 knots in this case.....

[411A]

I think it goes with out saying that you would declare an emergency...


Get a grip, Shaunny, it's not an emergency...it's an abnormal.
Fly the procedure and land, applying braking as necessary to stay on the pavement.
ATC won't help you as well (in fact they cannot do much...except call the fire services to stand by if needed:rolleyes:) so apply your training to best advantage.
Rocket science it ain't.

[OzExpat]

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! :}

[JAR]

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

[DFC]

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.

----------

Get a grip, Shaunny, it's not an emergency...it's an abnormal.

It would be some emergency if the aircraft ATC puts ahead blocks the runway. :eek:

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.

[KIGONYE]

What is this NDB u Speak of? ;)

[Love_joy]

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