All Engines Go Around from runway well below Vref

[A37575]

B737-Classic Recent simulator exercise. Heavy landing and bounce and delayeed action by startled PF means airspeed below Vref by 15 knots by the time the thrust levers are fully opened up and N1 reached GA thrust or more. Flap 40 Vref was 130 knots.

As this situation is similar to stall recovery with ground contact imminent, what is the minimum speed the flaps should be retracted from Flap 40 to flap 15 assuming the gear is still down and the aircraft has attained a positive rate of climb? No windshear - just a ballsed up landing requiring a GA.

[GlueBall]

There is no hurry to retract flaps after a bounce in any airplane, so accelerate first in level flight over the pavement, ground effect will help you do that, initiate a shallow climb at Vref, then retract flaps to your go around setting. [I'm not a B73 jock].

[Old Smokey]

I thoroughly concur with Glueball on this, although, like him, I'm not a B737 jock any more - the principals are the same.

To put you in the comfort zone, 15 Kt below Vref for a B737 should still be above the stall, so the aircraft is flyable.Remember that Vref is 1.3 X Vs, whereas V2 (min) is 1.2 X Vs, so, although we don't have V2s for Landing Flap, a speed a bit below Vref should be no more dangerous (from a stall point of view) than for a Takeoff. If for example, Vs was 100 Kt, V2 would be 120 Kt, and Vref 130 Kt, so 10 Kt below Vref is totally survivable.

For all of the techniques Glueball describes, use them, they'e good value.

Regards,

Old Smokey

[A37575]

Thanks for good gen. There had been some discussion over coffee that the min speed to retract from Flap 40 to flap 15 was when the airspeed had reached Vref plus 15. Seems however from advice by Rainboe the correct min speed before going to Flap 15 is Vref Flap 40. Thanks again.

[stue]

I only fly the 737NG, so forgive me if I speak out of place.

the min speed to retract from Flap 40 to flap 15 was when the airspeed had reached Vref plus 15


I agree with Rainboe. On a standard app, you would be flying Vref40 + 5 anyway. When the decision is to Go Around the standard call is “Go Around, Flap 15” In that time, although TOGA has been pressed you haven’t increased your airspeed by 10kts, so why in this situation would you wait till Vref40 + 15 until you retracted to flap 15?

If below Vref however, I don’t think I would ask for the flaps to be moved until I had got the speed back to Vref.

Just my thoughs……

[PENKO]

Airbus have a procedure for this, TOGA 10. TOGA, rotate to 10 degrees pitch, keep the configuration. Once safely climbing away you do as per normal go around. But again, that's Airbus.

[Mad (Flt) Scientist]

To put you in the comfort zone, 15 Kt below Vref for a B737 should still be above the stall, so the aircraft is flyable.Remember that Vref is 1.3 X Vs, whereas V2 (min) is 1.2 X Vs, so, although we don't have V2s for Landing Flap, a speed a bit below Vref should be no more dangerous (from a stall point of view) than for a Takeoff. If for example, Vs was 100 Kt, V2 would be 120 Kt, and Vref 130 Kt, so 10 Kt below Vref is totally survivable.

I won't presume to debate the techniques, but one caveat on the comment comparing Vref-10 to V2: For the takeoff case your engines are already running at the power you want - if you've ended up well below Vref, there's probably a good chance that your engines have been brought to idle, or close to it. As a consequence, the engine response will be rather sluggish on many jets, especially turbofans.

As a result, if you fly the balked landing like a takeoff, you're going to be very short on energy. This accident in Fredericton (http://www.tsb.gc.ca/eng/rapports-reports/aviation/1997/a97h0011/a97h0011.asp) contains some of those elements. (Section 1.18.1.4 discusses the go-around/balked landing specifically)

[c100driver]

The instructor might have been confused with
Vref Flaps 40 is equal to V2 Flap15 with 15 AOB and another 15 kts is 25 AOB

or

Vref Flaps 40 + 15 is equal to V2 flaps 1. (engine failure in the go-around)

[mustafagander]

This scenario is quite doable.

The engine response could well be a little slower than you want, but you are over a nice flat surface and have ground effect to help. As soon as you have TOGA thrust you are laughing. It will make certified gradients on 1 and you have 2 as well as a lot less weight.

On the B744, we can fly away on 3 @ 412 tons, so a 4 eng G/A at MLW, 288 tons, is a piece of the proverbial. Even on 3 it's no big deal.

As for flaps, I would stay with landing flap until Vref achieved, then as per SOP.

[A37575]

There had been some discussion over coffee that the min speed to retract from Flap 40 to flap 15 was when the airspeed had reached Vref plus 15

Just to reiterate; it was only a small discussion, chaps. :)

[BelArgUSA]

Again, a Pprune storm in a cup of tea...
Go around as described in situation above (below Vref) is -
xxx
GO AROUND THRUST
FLAPS XX (say setting for your airplane)
PNF announces "POS RATE"
GEAR UP
Go around at Vref
xxx
Since none of you seem to know the Boeings...
The flaps position for go around is a gated flaps position.
So, if your memory is short, move your flaps handle into that gate.
xxx
That is for 707, 720, 727, 737, 747... shall I continue...?
I just crashed my rocking chair in final...
:}
Happy contrails

[FE Hoppy]

slot 9 = post number nine of this thread

MS = Mad (FLT) Scientist

TSB = Transport safety board (of canada)

TC = Transport Canada


I did some work with Air Canada a few years ago and they are mad keen on low energy go arounds. Mad keen on understanding the problem that is, not on doing them!!

[BOAC]

Just to reiterate; it was only a small discussion, chaps. :) - not to fret, A37, you'll get used to this here. Within a few minutes we have blood pressures raised, exclamation marks, shouting and a single-engined g/a in answer to your query on a 2-eng g/a. Imagine what the cockpit would be like for real with these characters......

Out of interest, I'm sort of with Stue on this and I would leave the flap until I had a positive rofc. The odd F/O's bounce below Vref I have experienced generates a fairly busy state of activity in the cockpit and the original 'startled' PF is probably sitting like a 'startled' rabbit anyway so you'll probably be calling for flap for a while until it sinks in. You may just finish up moving the flap yourself. Don't forget you can always have another free 'bounce' on the runway if you need it (just as you might on a g/a in the flare in CatIII) so a good idea to keep it lined up:)

[Roadtrip]

Power. Maintain landing attitude. Don't try to prevent ground contact again. Do not change configuration. Normal go-around when aircraft is stabilized and climbing away.

[411A]

Power. Maintain landing attitude. Don't try to prevent ground contact again. Do not change configuration. Normal go-around when aircraft is stabilized and climbing away.

Yup, pretty standard stuff, at least on the heavy jets that I have flown.

[Tee Emm]

Again, a PPRuNe storm in a cup of tea...
Go around as described in situation above (below Vref) is -
xxx
GO AROUND THRUST
FLAPS XX (say setting for your airplane)
PNF announces "POS RATE"
GEAR UP
Go around at Vref


The initial scenario described the situation where the speed had decayed up to 15 knots below Vref when the go-around was initiated. A bounce or extremely long high float comes to mind. In other words a low energy go-around. It would be incorrect and potentially dangerous to immediately select Flap 15 from Flap 40. It is not a normal go around procedure under the scenario presented and would not have been published in the AFM.

In fact the situation as described is approaching a stall recovery. In that situation you do not touch the flaps or landing gear while ground contact is imminent which it certainly is here. Only when the aircraft is climbing away from ground contact and speed at Vref or more would the normal go-around procedure apply.

While the remark was light-hearted I would not refer to the whole thread as a Pprune storm in a tea-cup. A low energy go-around with full flap and landing gear extended especially on instruments at night, is deadly serious flying and requires careful handling.

Read another recent Pprune post linked to a Canadair CL-5 crash after a low energy go around from idle thrust in IMC fog. A comprehensive report from Canada that recommends manually flown IMC go-arounds from the flare are important simulator training exercises. Most IMC go-arounds are from Cat 1 ILS minima or on full automatics via Cat 2 or Cat 3 ILS.

[BelArgUSA]

Sorry you dislike my "storm" in a tea cup, Tee Emm -
xxx
Whatever you want the maneuver to be called, we fly both in simulators.
One is called "Go around, all engines missed approach"...
The other is called "Stall recovery, landing configuration"...
xxx
Tell me which one you want me to fly. A, or B...?
I can also design a new hybrid procedure.
For me, the more training, the more money I made. Hooray...!
xxx
:D
Happy contrails

[FE Hoppy]

There is a certification requirement for this. This doesn't prescribe a procedure nor does it consider starting the manoeuvre at Vref-15 but it's called a landing climb and you must have landing climb speeds in the AFM. You may find that it's the same as VREF as one trick used in certification is to increase VREF to a speed that meets the climb requirement. Hence in some AC it's called Landing climb and reference speed. The gear is down and the flaps in the landing position.


CS 25.119 Landing climb: all-enginesoperating
In the landing configuration, the steady gradient of
climb may not be less than 3·2%, with –
(a) The engines at the power or thrust that is
available 8 seconds after initiation of movement of
the power or thrust controls from the minimum flight
idle to the go-around power or thrust setting (see
AMC 25.119(a)); and
(b) A climb speed which is –
(1) Not less than –
(i) 1·08 VSR for aeroplanes with
four engines on which the application of
power results in a significant reduction in
stall speed; or
(ii) 1·13 VSR for all other
aeroplanes;
(2) Not less than VMCL; and
(3) Not greater than VREF.