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-   -   Coasting onto stand. (https://www.pprune.org/tech-log/522108-coasting-onto-stand.html)

nitpicker330 26th Aug 2013 10:23

If the APU fails you have 6 full applications of the accumulator mate....from 8 to 10 kts more than enough to stop.
Remembering that the accumulator is certified and good enough to stop the Aircraft from landing speeds according to Boeing...( significantly faster than 10 kts )

And besides, the APU generator is "put on the busses" and stabilized way before you "cut both" If you left it that late then you deserve a cluster f***

It's been done in the circumstances I describe many many times in 40 years on 737's 727's DC-9's etc WITH NOT A SINGLE INCIDENT ATTRIBUTED TO THE PRACTICE.

So, get a life.

Are you sure YOU are a real Pilot.

Uplinker 26th Aug 2013 11:03


It's been done in the circumstances I describe many many times in 40 years on 737's 727's DC-9's etc WITH NOT A SINGLE INCIDENT ATTRIBUTED TO THE PRACTICE.

So, get a life.

Are you sure YOU are a real Pilot.

Oh dear, handbags at dawn?


OK, let me ask you this. Is this "procedure" of yours certified and approved by the aircraft manufacturers?

I only ask because when the company I fly for were looking at single engine taxying in, they took it very seriously and carefully. They got permission from the manufacturer and took advice and wrote a checklist for the procedure. Even then, owing to an unknown hidden software fault on some aircraft; when the engine was cut, the brakes were immediately applied fully on without any command from the pilots - very nasty. This was obviously unintended, and investigation discovered the fault.

Their checklist for single engine taxying includes: the APU has to be on line and stabilised. The electric Yellow hydraulic pump has to be selected on. The main engine in question has to be sufficiently idled and cooled. The aircraft has to be taxying in a straight line and with feet off the brakes on a straight taxiway clear of obstacles. Only then can we cut one engine. (The electrical busses only transfer to the APU generator when the engine is cut).

So back to your procedure; How would you feel if one day the brake accumulator was faulty, or when you cut both engines, you had an engine tailpipe fire warning distracting you as you coasted onto stand, and you ran over a ramp worker? It's just not the sort of unnecessary risk one would expect an airline pilot to take.

fireflybob 26th Aug 2013 11:04

A debate on coasting in to stand on a Professional Pilots forum - some kind of oxymoron?

Shaman 26th Aug 2013 13:16

At any interview, the following question will be asked of both pilots:

"Is this an SOP?"

If the answer is "yes" and a company reference can be provided that all will be well. If not...

tripilot 26th Aug 2013 13:23

Let's face it folks - it's a donkey move to shut both engines down before arriving on stand. No question.
All your are trying to achieve is the miss-placed adulation of the person in the other seat - it ain't gonna save a significant amount of fuel or ANY time and all it could really increase is the risk factor in you day.
Thanks for all the opinions, I'm a little suprised to hear people who think it works though. Any response from our Emerald Isle colleagues? Is this an SOP? Is it taught on the line? From what I've seen of crew that have previously worked for them they are very good and don't stray away from SOPs in the least.

bugged on the right 26th Aug 2013 13:28

I am a retired FE and one of the things I was paid to do was to look at the scenario and try to anticipate the unforseen consequences of certain actions. Having seen and heard about the results of some smooth operator's non standard aviation tricks I can only advise pilots to keep it standard. When it hits the fan you will find your capacity is greatly reduced and you need a standard act to fall back on with the normal checklists while you concentrate on the abnormals.
Can you imagine in a court being asked by a lawyer why you saw fit to deviate from SOPs?
SOPs, checklists and limitations are there for a reason and it is not for the likes of us to bend them to suit ourselves.

myekppa 26th Aug 2013 13:31

This thread's quite hilarious.

I now understand why some aussie pilots have earnt the 'Austronaut' title, based on Nitpickers demeanour. Mate.

A bit unfair really as they usually make far better pilots than cricket or rugby players.

Basil 26th Aug 2013 15:28


they usually make far better pilots than cricket or rugby players.
Do you mean they're better at piloting than other cricket or rugby players are or they're better at piloting than they are at playing cricket or rugby? :}

Bas - didn't even remark last score to Oz DiL; she might hit me ;)

BARKINGMAD 26th Aug 2013 15:40

WHAT WAS THAT WARNING LIGHT?
 
This is a strange sort of behaviour to advocate.

My simple NG throws up all sorts of lights, blue and amber with MWS cautions even when only one is shutdown. I brief my oppo, as we decide to stop the appropriate (usually RH donk), to expect lights various, and as they occur they are all checked and accounted for.

So as you coast onto stand and even more system failure annunciators are lighting up, can you be absolutely certain NONE of them is something CRITICAL?

Methinks this profession's aptitude testing needs a radical overhaul to identify and isolate (chop!) those who wish to operate like this, or defend those who do!

Ozlander1 26th Aug 2013 17:12

Me thinks I'll start coasting into the garage, save a bit of fuel, don't you know. :ok:

Trackdiamond 26th Aug 2013 18:29

roller coaster risk management
 
Here is your gotcha!

Imagine taxiing in heavy with a tailwind, Engines fuel cut off, roller coasting in with a smug grin...and RingRing!!! APU fire..AND some ramp vehicle is about to intercept your path...and need I add some unruly passengers at the sound of engines being shut down decide to stand and remove luggage from over head bins...and Mr.Murphy decides to thrown in a brake failure scenario or nosewheel deflation...that cockpit ain't gonna smell too good! Now imagine in command is ...Mr. Bean!

DownIn3Green 27th Aug 2013 06:05

So in reply to Uplink...He is exactly correct...My experience with a major US carrier (Eastern Airlines) was shut down an engine on taxi in...But I was on the 727 and it was always #2...to lessen the footprint.

As far as powerback goes...yes we did that also...but only on certain gates at certain airports...Reason? Powerback requires a trained ground crew (with goggles) to direct you. Additionally, all GSE needs to be secured...lots of wind hitting the terminal, gate area...

Another issue was 2 engine powerbacks...we did it but only if taxi wgt was less than 160,000 lbs...(MGTOW of some of our 727's was 191,000)

It is always a physics vs cost over-ridden by safety

Sometimes good piloting, sometimes foolish...

Mach E Avelli 28th Aug 2013 23:55

I have flown two types where power-backs were both approved in the FCOM and allowed by SOP. Other SOPs that I have operated with permitted one engine shut down during taxy-in and my current four engine type allows two engine shut down - but the engines that run the hydraulics must be kept running until brakes are parked. This is called CDF (common dog f...).

I have never flown a type where coasting with all engines off was permitted. Doing this is called a CLM (career limiting move).

nitpicker330 29th Aug 2013 08:12

Ok, let me put this in CAPTIALS so you guys can read it. :sad:


I HAVE NEVER DONE OR NEVER WILL "COAST IN " TO THE STAND. I DON'T CONDONE THE PRACTICE AS I AGREE IF SOMETHING GOES WRONG YOU WILL BE IN A SPOT OF BOTHER OPERATING OUTSIDE SOP's :ooh:

ALL I'VE SAID IS THAT IT HAS BEEN DONE MANY TIMES IN 40 YEARS IN "SUITABLE " CIRCUMSTANCES WITHOUT INCIDENT THAT I'M AWARE OF.

Ok?? :ok:

nitpicker330 29th Aug 2013 08:18

Trackdiamond:-----don't forget to add the Earthquake occurring at the same time you enter the stand or the piece of space junk re-entering the atmosphere and then hitting you as you pull in to the stand as well as a sneezing fit...!!

Anymore scenarios you'd like to think about????!!!;)

Uplinker 30th Aug 2013 07:34

No, you actually said more than just that:-


1/ I haven't ever done it and won't
2/ I never suggested being daft and doing it in a wide body entering a confined area to an Aerobridge!!

3/ for smaller 737 ops in quiet open un-congested aprons ( with steps ) with a serviceable RUNNING APU I don't particularly see the serious problem if you cut both 60' before the stop point.

Silly and pointless? Maybe..........Dangerous? No.
You also said the accumulator gave you 8 applications of the brakes, but then you changed that to 6.

When you're in a hole.... stop digging !

nitpicker330 30th Aug 2013 08:04

Haven't flown the 737 for 20 years so sorry if I changed the accumulator from 8 to 6 after I researched the books. You must have been bloody quick as I changed it no more than 5 mins later!!!

My opinions haven't changed and I think I've been pretty consistant throughout, pity some here can't read.:ugh:

aviatorhi 30th Aug 2013 10:27

Coasting into the gate is a dumb idea at best. Never do it myself (and I'm usually a gung ho type), apart from fooling around in the sim, and in that case I shut the engines down when clearing on the high speed at 80 knots to see if I can make it to the gate.

Can it be done? Yes, absolutely, but you leave yourself potentially one failure away from no steering or brakes.

Also, the tools bragging about the accumulator, what's your recourse when the leak is in the brakes themselves, or a return line (has happened to me). On the 727 we at least have pneumatic brakes.

Additionally, when doing single engine taxi I strongly advise to keep the engine which pressurizes the HYD system on which the NWS is to be the last one shut down after a complete stop.

Citation2 1st Sep 2013 13:54

Another cowboy undocumented and invented procedure .

Boeing 77W 1st Sep 2013 18:21


However I really would like to know if this is something that has been suggested within the airline to save fuel and time. Further to this, the same low cost airline only uses 1 minute cool down time for its engines rather than the Boeing time of 3 mins - sad I know but I've timed it!
It has not been suggested by the company. This sounds like individuals going outside of the SOPs. I've spoken to a couple of guys, one of whom has seen it done several times.

The company also uses a 3 minute cool down period in it's SOPs as per the Boeing recommendation, one of the considerations for single engine taxi. So again. Sounds like people operating in their own fashion.


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