B737 SETO - Single Engine Taxi Out

[+TSRA]

Fortunately some of us work for airlines, where chief pilots take the downsides of SETO seriously, and steer cleer of it for those reasons.

What also needs to be taken into account is average taxi length - it's rare to taxi out for more than 15 minutes where I fly, making any potential gains quite miniscule, compared to all the risks. Now, if you fly in USA with the 3 hour conga lines instead of A-CDM... then it makes much more sense.

And that is why at the company I work for, the decision to conduct or not conduct SETO is left to the pilots in the moment. If a CP looks at their operation and identifies that, due to average taxi time, there is more risk than reward, then that CP should not implement the procedure. However, a CP working at an airline that does operate to airports with average taxi times that exceed 25 to 30 minutes with aircraft sitting in a line may come to a different decision. I've spent the better part of 20 years working for airlines where SETO was a well-established practice - turboprops to jets. At every company there were robust rules of when and when not to conduct SETO. Every year the ops office would examine the occurrence record for the fleet, and in some cases SETO was identified as a large enough contributing factor over the year to warrant the publication of additional rules. For example, when a new runway was added at my base airport, it became obvious to everyone at every airline that utilizes the airport that there was a hot spot at the intersection of four taxiways as the rate of taxiway incursions skyrocketed. A part of that was the poor design and signage of the intersection, but another part was that is where many pilots reported they were either just starting or just finishing an engine start. By this point they had been taxiing for about 10 minutes with another 5 minutes to go, so not unreasonable for using SETO. My airline started by publishing a guideline that if conducting SETO, the engine had to be fully started and checklist complete by that intersection or had to be started after passing through that intersection. That seems to have done the job as the rate of taxiway incursions at that airport has dropped back to what is considered the background rate.

[extreme P]

Originally Posted by olster

Yup, love it when pprune gets personal from all the experts out there. Firstly SETO has not been around for many years. Most CPs (sic) know the square root of foxtrot alpha. The fact that there has not been an incident does not mean that the procedure has been robustly risk assessed. I am not going down the road of saying which aircraft I fly or have flown as we are now in the standard willy waving pprune scene whereby x has eg 28,000 and ergo they are the fount of all wisdom. I have flown a mixture of Boeings including 737 and 747 ( including instructor / examiner) also Airbus A340 and instructor on A380. I currently work as an instructor for a well known manufacturer. Hope that helps. I don’t pretend to be the definitive expert but I have been around.

How many times have you done SETO with a B737?
Do you find your A380 instructor experience provides you a unique insight into B737 SETO ops?

[PENKO]

Originally Posted by olster

Yup, love it when pprune gets personal from all the experts out there. Firstly SETO has not been around for many years. Most CPs (sic) know the square root of foxtrot alpha. The fact that there has not been an incident does not mean that the procedure has been robustly risk assessed. I am not going down the road of saying which aircraft I fly or have flown as we are now in the standard willy waving pprune scene whereby x has eg 28,000 and ergo they are the fount of all wisdom. I have flown a mixture of Boeings including 737 and 747 ( including instructor / examiner) also Airbus A340 and instructor on A380. I currently work as an instructor for a well known manufacturer. Hope that helps. I don’t pretend to be the definitive expert but I have been around.

Yet once you become chief pilot somewhere, I’m quite sure you will not abolish the practice of single engine taxi operations. The argument that the aircraft might have to come to a complete stop necessitating ‘triple fuel flow’ on the live engine to start moving again will be negated by the hundreds of other crews who are able to sensibly shut down an engine taking all variables into consideration, coasting in beautifully and effortlessly to the gate.

But you have piqued my curiosity. How does your current employer (the aircraft manufacturer) regard single engine operations? Do they agree with you? Do they discourage the practice? And do they communicate that to the pilots of their aircraft?

[olster]

Penko, I am not able to answer that question. The thread dissolved into a personal and profane diatribe towards me for bizarre reasons. I completely understand differing opinions and accept the rationale for SETO in terms of fuel saving, which again personal opinion I believe is ‘risky’ for well documented reasons. As people are so interested the last 737 airline I worked for carried out SETI (including me) with many caveats. They risk assessed SETO and found it wanting. The main reason being SA on taxi was compromised and engine start is supposed to be monitored by both pilots. I am not at liberty to say what the manufacturer thinks of the procedure but a straw poll of colleagues were aligned with the view I have given. Hope that helps.

[framer]

I will do it when the rate of taxiway and runway incursions stops increasing, flatlines, and then starts decreasing.
We need to have our minds on the job folks.
We are splitting our attention between more and more things as technology increases and our attention is a finite resource.
Last week I was lining up at night, we had already been cleared for takeoff when my f/o told me that new weather had become available at our destination …..where was his mind? Were we on the centerline? Were the flaps set? Had the landing traffic cleared? Was the radar painting anything on our departure track? Were the packs ON? Were the FMA’s armed? Was the trim set? Was it the correct intersection? Was it the correct runway?What was our target attitude airborne? ……There is a long list of things you could use your limited attention for just prior to takeoff. At the moment, globally, we are not doing a good job of allocating that attention. Maybe this is because of the ability to update our iPads weather function or maybe it’s a combination of lots of things but we need to regroup, pair it back, and keep it simple or we are going to have another Tenerife on our hands.

[Rozy1]

I agree with my reluctant colleagues here and even though my bosses promote it, I rarely SETO because of the many risks and less desirable factors already described in this thread. Since my company operates more 737s than any other carrier, however, I do understand management’s desire to potentially reduce fuel usage on several thousand flights per day.

I won’t say no Willy waving, then do precisely that. That was interesting.

[172_driver]

It's up to every captain's risk management to assess whether single engine taxi out and/or in is appropriate, no right or wrong. I am no conspiracy theorist and if the fleet office says it's saving fuel I have no reason to believe otherwise.

[Say again s l o w l y]

We put SETO and SETI into the Ops manual back in 2013 and we all started to use it then. There wasn't a single incident or issue with it. It is so routine that I am genuinely amazed it is even a discussion point. Yes it has to managed properly, but so does everything.

[70 Mustang]

Something to consider…

I wouldn’t want to leave the gate area or have the pushback tug disconnect until I knew both engines and generators were working. A bit of a palaver if, after some single engine taxi, to approach the departure end of the active runway, only to then see that the other engine or generator would not operate properly.

it’s risky enough to shut down at a remote holding point, then hope they both start up when your slot comes up.