Engine response time

[JoeDiamond 67]

On 2/28/2017 at 2:32 PM, Chock said:

they even tell pilots to put the wheels down later on final approach these days so that there is less thrust required to maintain speed when still a few miles from touchdown.

I have a difficult time believing this is accurate information.  What is your source?

The trend in the airline industry has been in the opposite direction placing more emphasis on stabilized approaches.  The carrier I work for has certainly never suggested this technique, nor have I heard it from anyone I know working at other carriers.  We are actually encouraged to put the gear down early if you think you need the extra drag to ensure a stabilized approach.

[Chock 17,769]

2 hours ago, JoeDiamond said:

I have a difficult time believing this is accurate information.  What is your source?

The trend in the airline industry has been in the opposite direction placing more emphasis on stabilized approaches.  The carrier I work for has certainly never suggested this technique, nor have I heard it from anyone I know working at other carriers.  We are actually encouraged to put the gear down early if you think you need the extra drag to ensure a stabilized approach.

It varies between carriers, some are told to leave it later, some not. My source would be from personal observation and from the SOPs I've produced for a few airlines over the years, which vary between carrier even in the same SOP manual. For example, in the A320 SOP's I did for MyTravel and Viking airlines a few years back, many procedures in those SOPs would have stuff listed which might say in brackets after it (not MYT) or (not VKG), so SOPs differed even between sister companies using the same types and sharing the exact same SOP manual. It was al sorts of things, such as one airline's crews being allowed to use Expedited Climb mode on their A320s and the other airline's crews told not to do it since it increased wear on the engine.

Back to dropping the gear though, you will have some SOPs insist you have it all hanging out at no later than the the FAF, some before that, some at specific minimum altitudes or DMEs. I know many new first officers these days are trained to have everything stabilised a long way out from the runway threshold, but that is probably to ensure they don't have problems when lacking in thousands of hours on type, so more experienced pilots might frown upon such a waste of fuel and excess of noise on approach. Having it all out early, whilst definitely helping with a well stabilised approach, definitely uses more fuel and it may also incur the wrath of the surrounding householders at some airports, when there are strict noise abatement procedures in place, since having those Dunlops dangling and all the flaps out early is going to require considerably more thrust, plus of course an aircraft in dirty config itself makes more aerodynamically generated noise too. As far as I know, most airports are going to want airliners to be keeping about 160 knots on the clock until fairly late into the approach; in some aircraft that is easier to do with the gear up, some it is easier with the gear down.

One thing is for sure, I know I used to see a lot more airliners coming into Manchester airport with everything hanging out as they passed over the town centre of Stockport (I'm talking in the Seventies here), but nowadays - especially Ryanair and Easyjet - 737s and A320s will be popping the gear down well after they have passed over the town, which is maybe a mile or two later into the approach, than was commonplace thirty or forty years ago. It's not going to be the exactly same in terms of stability and such for a 'Bus versus a Boeing though, since the 737 has a higher approach speed than the A320, so an A320 will lend itself more to getting the gear down later.

If you ask about among a wide variety of pilots, you will probably find about as many 'we are told to do it like this' opinions as there are carriers.

[skelsey 765]

Just to add - as Alan will know, the Airbus factory SOP calls for flap 2 and gear down by 2000ft AGL. The Big Airline has a "low noise supplementary procedure" published which allows, basically, for gear extension to be delayed provided a bottom line for extension is briefed such as to permit the stable approach criteria (at 1000R) to still be met. I imagine other airlines will have similar.

Not sure about the form of wording for the 737 in particular but I would be surprised if there wasn't some similar provision there to permit some flexibility whilst ensuring the stable approach criteria are not exceeded.

Edit to add: Meant to say - Airbus do also stress that the gear is the greatest form of drag available on the aircraft and that crews should not hesitate to take the gear early/out of sequence if necessary to slow down/stabilise the approach.

[ALF1 15]

2,000 feet seems the standard for GS intercept at which time you would extend gear, arm speed brake, and flaps 15 speed down to 160 or so, bout 7-8 miles out. Most conservative carriers I've heard want the approach stabilized by the OM, or 5-6 miles out. A large carrier in Europe I've heard places a 6 mile ring around the airport in the MFD as a reminder to extend the gear. I guess SOPs are different all over.

[Andrea1 6]

Hi,

the Big European low-cost airline employing the B737-800 has a "low-drag" (fuel saving) approach policy mantaining flaps 5 (i.e. 170 kts/flaps 5 configuration) till (usually if others considerations are not relevant) 5 miles from the rwy (VMC) or 6 miles (IMC) . 

As Alberto has pointed out: there the pilots have to place a 6 miles ring around the rwy in their CDU FIX page to "draw" this circle showed in their navigation display as "reminder" for flaps extension .

Happy Easter to Everyone!

Ciao

Andrea Buono

[Driver170 42]

14 hours ago, Andrea1 said:

Hi,

the Big European low-cost airline employing the B737-800 has a "low-drag" (fuel saving) approach policy mantaining flaps 5 (i.e. 170 kts/flaps 5 configuration) till (usually if others considerations are not relevant) 5 miles from the rwy (VMC) or 6 miles (IMC) . 

As Alberto has pointed out: there the pilots have to place a 6 miles ring around the rwy in their CDU FIX page to "draw" this circle showed in their navigation display as "reminder" for flaps extension .

Happy Easter to Everyone!

Ciao

Andrea Buono

4 VMC and 5 IMC

[Piepal 1]

8 hours ago, Driver170 said:

4 VMC and 5 IMC

Yes landing gate of 1000 ft for 5 NM IMC or 500 ft for 4 NM VMC

[Driver170 42]

Range Ring in the fix page (3x Cruise level / 10nm / 4/5nm)

Passing 10nm you need to be 3,2,1 = 3,000ft, 200kts and Flap 1. (10nm Rule)

500’ continue/go-around call

All used to Prevent HEA (High Energy Prevention)

[Andrea1 6]

20 hours ago, Driver170 said:

4 VMC and 5 IMC

Hi Vernon,

you're right..5 IMC/4VMC

Best

Andrea

[achutchison 26]

Why does there have to be a stupid rule for everything? Trust in experienced pilots' judgment and let the new guys learn from that.

[ALF1 15]

Because when it comes to flying a fleet of airplanes airlines need to be consistent. The less you leave to subjectivity the better and safer everyone will be. SOPs are an absolute necessity.

[scandinavian13 5,192]

21 minutes ago, ALF1 said:

The less you leave to subjectivity the better and safer everyone will be. SOPs are an absolute necessity.

There is a fine balance, here, though.

If you drag too much into the realm of black and white, if you find a grey situation, the black and white may not address it, and someone who's too used to having a black and white answer will be too mentally reliant on having an answer, instead of using judgment.

I'm in agreement for having an SOP, but I also feel that there's a lot in aviation that needs to be left open to judgment calls. As an example, control facility SOPs can be extremely detailed, but in the end, they all usually have some clause related to "or as necessary to handle the operational situation."

An example is runway selection. By default, if the wind is calm, Dulles will be in South Ops (landing on the 19s; departing on the 19s and 30). If a bunch of European departures were going out all at the same time (would need to be vectored around to the north), it may be operationally more efficient to 'break' SOP and use North Ops (landing on the 1s; departing on the 1s and 30) until all of the heavies are out of there.

The inverse may also be true. The highest throughput at IAD is about 110 aircraft per hour using 19L, 19C, and 19R for arrivals and 30 for departure. If I have a bunch of arrivals in a compacted time slot, and very few departures, even if the wind is from the north at 5-6 knots (ish), I may still use South Ops to get all of those planes in relatively quickly without backing things up at the Center or TRACON level. That's a judgment call though. If you remove that, you remove efficiency from the system, and you condition people to simply be computers. If X, then Y. If A, then B.

...but what happens if you get Q?

[downscc 1,327]

1 hour ago, scandinavian13 said:

If you drag too much into the realm of black and white, if you find a grey situation, the black and white may not address it, and someone who's too used to having a black and white answer will be too mentally reliant on having an answer, instead of using judgment.

There was once a pilot at the USAF Combat Flight Training school at Nellis AFB (the AF Top Gun School) that had a running bet that he could shoot down any pilot in less than 15 min.  No one ever won the bet, and as you can imagine there were many takers.  What he did was simple, he simply thought outside the box and the trainees trained to respond to A or B simply didn't know what to do when Q happened.  He probably saved a lot of pilot's lives with this lesson.

[ALF1 15]

Agreed many things are best left to pilot's discretion. Otherwise you would be making robots out of human beings and the pilot in command is the final authority. That said though I am a big believer in SOPs and internal regulations. FAA regs may not be enough for safety. A while back in a field I will not disclose a flight was to land on a fairly short runway. It had just rained and the runway was wet. Further, the ceiling and topography would force the pilot to land with a 10 knot tailwind and the runway had just been resurfaced. This made for poor to nil braking action. The airplane skidded off the end of the runway. My belief is that an internal airline regulation should have existed  prohibiting the pilot from attempting this landing, instead of leaving it to discretion. When an internal regulation exists, the airline is relieving the pilot from a very tough call--one he might even feel pressured to take reluctantly and ill adviced.

Then you have insurance requirements. For example, I don't know if this actually followed but if I were the insurance underwriter I would set forth conditions such as this one for coverage eligibility.

[skelsey 765]

8 hours ago, scandinavian13 said:

If you drag too much into the realm of black and white, if you find a grey situation, the black and white may not address it, and someone who's too used to having a black and white answer will be too mentally reliant on having an answer, instead of using judgment.

I'm in agreement for having an SOP, but I also feel that there's a lot in aviation that needs to be left open to judgment calls. As an example, control facility SOPs can be extremely detailed, but in the end, they all usually have some clause related to "or as necessary to handle the operational situation."

A good summary as usual.

The one point that I would make (and it's an interesting discussion, though only peripherally related to this thread) is that on the specific point of approach gates -- the problem is that, as you and others who have commented on that his this thread will know, unfortunately the data says that high energy approaches and ensuing landing overrun accidents are all too common. Whilst of course the Captain must always retain the authority to deviate from SOPs where safety is an issue, there clearly remains an issue with guys and girls flying high energy, unstable approaches on the premise that 'we've done it before/seen it done before and it'll be OK'. Setting clear boundaries in this arena in particular is very useful if for no other reason than empowering an FO observing a cluster of an approach to speak up with clear authority rather than enter in to a battle of 'my judgement against yours' during a critical stage of flight. If you're not in the slot, you're not in the slot: it's as simple as that.

I don't know that much about the airline in question's procedures, but I would imagine that the gates above are most likely guidelines  - in other words, if you're missing them, alarm bells should start ringing -- and the actual 'hard' gate at which the criteria must be met else the SESMA goes off etc will be a little further down (ie 1000/500 aal).