"Center the Bug"

[HuggyU2]

I brought this topic up elsewhere with military pilots I know, and it turned into a pretty good thread.  A number of them are airline Captains and provided great perspective.   I doubt I'll see anything new here... but since it was quite a fun and lively discussion, I'll ask.  

"Center the bug"... it's what airline pilots do, right? When you roll out of the turn in LNAV, you put the heading bug at 12 o'clock. "A married bug is a happy bug."  "Heading to follow..."

In 28 years as a military pilot, I seldom cared where the heading bug was if I was navigating on something other than a heading.  In the U-2, I bugged my flameout heading.  On final approach, I could bug the go-around heading... but I'm mildly confident I can fly runway heading without a heading bug.  Call me crazy.  

But now... I'm an airline pilot... and in training, I was constantly being reminded to "center the bug" while in LNAV. So... I put on my "I believe" hat, and centered it.  

Now that I'm on the line, I find it has no useful purpose for me, so I don't do it anymore. The big difference is that recently, the Captain I'm flying with scolded me for being an "outlier" who needs to conform with the rest of the pilot community. He was pretty annoyed. He couldn't tell me why he does it, but he came just shy of insisting that I do it.  

I've flown with other Captains that, on my leg, will constantly adjust the bug 2-3 degrees as the heading changes over the course of the flight. Dude, knock it off! If I wanted the heading bug centered, I'd do it. And having YOU mess with my bug on my leg is non-SOP at my airline. Don't like that I'm not doing it? Then tell me you want it done. You're the Captain, and I'll comply!

So... what's the big deal? Is there a reason y'all "center the bug"? Will it save me from an FAA violation, or even death?? It certainly isn't "procedure"... but sure seems to be a big deal where I work.

 I've learned from others that the Airbus doesn't display a bug in LNAV, and neither does the MD-11.  I'm also aware that I have to center the bug before I mash down on the 737 HDG button... which will add 2-3 seconds to when the jet begins to turn.  Got it. I'm looking for a more earth-shattering reason than this sort of thinking.  

 

 

[ThreeHoler]

It has to do with some old school mode reversion stuff that modern airliners generally don’t have a problem with.

There are several good techniques for the bug. Leave it centered and you can always easily revert to it. Crossing the ocean? Turn it 45 off so you can detect an unintentional reversion or have your contingency turn set up.

My OCD says center it. But that’s just my disease. It is funny when you fly with someone who wants it centered and someone who doesn’t and the slap fight ensues.

[FourFans]

If it's your leg, do what you want with the bug.  If you're the Captain/AC, pipe up on how you want it run.  Don't mess with someone else's way of flying unless it's outside of procedure or it's a technique that can end in a violation death. 

I think it's just a stupid detail for sim instructors to be constantly harping on in order to browbeat the importance of a solid cross-check.  That may service a purpose.  Once on the line though...not helpful.

[raimius]

Ask everyone why they do it.  If they don't have a good answer, that's probably a hint at poor systems knowledge or that something that used to have value is now just useless habit.

...I can't tell you much, because we just got heading bugs in the last couple years, and they are just for personal SA.

Edited February 12, 2018 by raimius

[gearhog]

I was taught to always "bug up" at a previous airline to expedite a turn to any vector you may be given. Engaging HDG SEL without the bug centered was a crime, especially if the aircraft began a slight turn in the opposite direction while you twist in the correct heading. We now have course, not hdg, at the top of our map mode display. When given "turn 15 degrees left for spacing", I find it easier to go directly to the MCP, subtract 15, and twist/bang before the Capt can finish the radio call if the bug is centered.

My last trip, Capt would reach up center the bug on my leg, so I began to set in the next LNAV course drift killed HDG well before the turn point. When he reached up to change it, I'd say "That's the next heading" and twist it back. That created an incredible amount of tension (and personal entertainment).

[FUSEPLUG]

I just do it because it’s a good way to kill 1.5 seconds of a 5 hour transcon. 

[Danger41]

My favorite one is when I see guys move the heading bug 1 degree when flying a PAR instead of just flying the airplane. Few things get me from 0 to seeing red faster than that.

[UPT-hopeful]

I center the bug then throw it off a few degrees just to make the captain squirm

[Champ Kind]

I’d usually keep it centered for the vector reason listed above as well as having it in a somewhat useful position should we need to go to HDG mode and deviate for weather while at cruise. Setting it to the next leg’s heading on a low level in anticipation of off course maneuvering or the IP to DZ heading were also common techniques as well, but they were exactly that...techniques. Certainly nothing worthy of flipping your shit.

[Sneedro]

What else am I supposed to do during cruise? 

[JeremiahWeed]

10 hours ago, HuggyU2 said:

In 28 years as a military pilot, I seldom cared where the heading bug was if I was navigating on something other than a heading.  In the U-2, I bugged my flameout heading.  On final approach, I could bug the go-around heading... but I'm mildly confident I can fly runway heading without a heading bug.  Call me crazy.  

The big difference is that recently, the Captain I'm flying with scolded me for being an "outlier" who needs to conform with the rest of the pilot community.

I've flown with other Captains that, on my leg, will constantly adjust the bug 2-3 degrees as the heading changes over the course of the flight. Dude, knock it off! If I wanted the heading bug centered, I'd do it. And having YOU mess with my bug on my leg is non-SOP at my airline. Don't like that I'm not doing it? Then tell me you want it done. You're the Captain, and I'll comply!

So... what's the big deal? Is there a reason y'all "center the bug"? Will it save me from an FAA violation, or even death?? It certainly isn't "procedure"... but sure seems to be a big deal where I work.

 I've learned from others that the Airbus doesn't display a bug in LNAV, and neither does the MD-11.  I'm also aware that I have to center the bug before I mash down on the 737 HDG button... which will add 2-3 seconds to when the jet begins to turn.  Got it. I'm looking for a more earth-shattering reason than this sort of thinking. 

I'll take a shot at this.  Before I do, I will caveat everything by saying I think Boeing's approach to heading bug logic is extremely flawed and I share your frustration with this tedious routine we follow as we fly.  My frustration lies in the poor design of the system.  However, I do feel that the technique of matching the bug is a necessary evil for a few reasons.  I've flown four Boeings (737, 757, 767 and currently fly the 777).  I've also flown the A320 and the MD-11.

Without getting unnecessarily aircraft specific, I'll just say that there are far better ways to skin this cat and the heading select logic found in other aircraft is vastly superior in my opinion.  As you mentioned, the logic includes removal of the bug when not in use.  Some systems also can "remember" which direction the heading knob was turned prior to actually engaging the heading mode.  In addition, some systems put the heading bug in a dormant state once the aircraft has captured the selected heading.  By this I mean it's not always "hot" like on a Boeing and turning the knob to a new heading will not create an immediate turn.  The button must be actuated again to begin the turn. 

I offer this info only to illustrate that someone's background in other aircraft can set up the potential for errors when "muscle memory" and former habits potentially surface at the wrong time during high workload situations.  So having everyone start on the same page and keep them on that page when things get busy has huge value in my opinion.  Also, FWIW, matching the bug to current heading is procedure at FedEx and was at United when I worked there - not sure about now.  You may not be able to find that specifically addressed in your books but I would argue that's it pretty much procedural with most Boeing operators whether they put it in print or not.

So, one of the big reasons we do this is standardization.  We successfully put two (or more) pilots who've potentially never flown together and only met an hour or two prior together on flights routinely.  A major reason this happens uneventfully every day is standardization.

You didn't care about the U2 heading bug at times and at others you chose to do something with it you found helpful.  In a single seat aircraft you have that luxury since your techniques and opinions are the only ones that matter.  At "brand-X" you don't have the same leeway without creating the potential for confusion.

I'm not trying to make matching the bug to your heading a bigger deal than it really is, but not doing it can lead to other issues - some big, some small.  Maybe it's in the sim or out on the line, but depending on who you're crewed with, what seems like a little thing can turn into something big in rapid fashion.

For example:

While we all know assumptions are bad and making mode changes without verifying the variables is bad technique, I'm sure you've seen someone just reach up and push the heading knob when ATC clears you to "maintain present heading".  Their assumption is the bug is matched - which at many airlines is a valid assumption since it's procedural (not excusing not checking first - but we are dealing with fallible humans).  So, you get rushed and give the jet to the other guy in the descent so you can load and brief the approach.  Today, you left the bug "over your shoulder" and it's not even visible on the ND.  So, he attempts to comply with ATC's instructions and assumes the bug was matched.  When the unexpected turn starts, he realizes it isn't and now has to recover.  Recovery techniques are going to vary from rapidly dialing in your old current heading (if he remembers), using heading hold, going back to LNAV momentarily, etc.  That doesn't even account for the startle factor which will vary based on proficiency level, fatigue, distraction, etc. and may delay the recovery attempt while he tries to figure out what happened.  The bottom line is, a matched bug or even something close is going to be more forgiving of bad technique and avoid potentially bigger issues.  On a side note - I highly recommend using "Heading Hold" when complying with "maintain present heading" for this very reason (technique only).

Since your technique means the heading bug could be anywhere at any time prior to you using heading select, by definition, you have to select something you want with the MCP knob before you engage Heading Select ("center the bug before you mash down" as you put it).  On the other hand, those who match the bug can immediately engage Heading Select and then turn the knob to the desired heading.  That distinction is important.  Since your technique involves an extra step, EVERY TIME you use Heading Select, that's something the pilot monitoring has to be looking for as well.  Since it's non-standard, that's going incumbent on you to make sure he's aware that needs to be in his cross-check.  For example, ATC gives you a 220 degree heading change "the long way around" to the right.  Any heading selected on the left of your compass rose when the button is pushed is going to command a turn to the left.  So, are you going to dial in your current heading, THEN engage Heading Select and then command the turn to the right?  Every time?... no matter what?  Would it ever be possible (habit, task saturated, fatigue, etc) you might first select the desired heading and then engage heading select commanding a left turn you would then need to reverse?

I'd guess it's unlikely these issues are going become life or death matters.  If they snowball thanks to a really bad day or just Murphy's law, they could still turn ugly with the FAA.  Is it really worth any issues arising because you want to make a point?  Most likely your airline pays you a pretty good bit of money to fly their jets and they want them flown their way.  Why not make it easy on yourself and your crew members and play along?

Edited February 12, 2018 by JeremiahWeed

[gearhog]

I really want you two guys to fly together so I can be on the jumpseat with a bag of popcorn.

[Buddy Spike]

Man I miss the days we were all talking about cool stuff like killing bad guys and how WSOs aren't real people.  Now we're all airline pilots and this is our life.  Ugh.

With that said, it was explained to me by a CKA while flying down to Managua is that on the 737, when LNAV fails it reverts to HDG. That's fine, until you're in the low altitude environment flying a STAR around mountains (Latin Terrain specifically) and LNAV fails and the aircraft takes off hard left or right while you're trying to figure out what just happened in the weather and at night.

 

[JeremiahWeed]

2 hours ago, torqued said:

I really want you two guys to fly together so I can be on the jumpseat with a bag of popcorn.

I think you'd be disappointed.  I don't care that much about it.  I've just seen it screwed up enough and flown with certain folks who absolutely lack any level of mental flexibility to work outside the lines occasionally.  Huggy asked and I tried to provide a semblance of a valid answer.  Buddy Spike added another one.

[SurelySerious]

1 hour ago, Buddy Spike said:

Man I miss the days we were all talking about cool stuff like killing bad guys and how WSOs aren't real people. 

Of course. 

[SocialD]

Eh, I found that being a chameleon is helpful.  I don't have a "valid" reason for where I put the heading bug, so I just do whatever keeps the Captain (or other FO), from freaking out.  As long as it's not dumb or dangerous, then life is too short to worry about such bullshit.  If either of the others pilots are dickheads, then I may screw with them and do whatever they don't like, just for my entertainment.  1 degree off for the OCD types is pure entertainment.   

[ThreeHoler]

I like the Airbus setup. Push (hdg sync) pull (hdg sel) turn (aircraft turns in direction selected by the way you spin the knob to the selected heading).

[Hacker]

At my current airline and in my jet, they are fairly militant about keeping the bug centered.

In all my years of military flying, I never did this.  Like Huggy, I used the heading bug for other stuff (like "pie in the sky" MOA maintenance, yeah baby!!).

I don't have a preference or opinion contrary to that, so I just do it.

Edited February 12, 2018 by Hacker

[Hacker]

18 hours ago, HuggyU2 said:

 the Airbus doesn't display a bug in LNAV

Not sure which "the Airbus" you're referring to, but the one I'm on has a heading bug regardless of the status of modes.

[gearhog]

2 hours ago, SocialD said:

Eh, I found that being a chameleon is helpful.  I don't have a "valid" reason for where I put the heading bug, so I just do whatever keeps the Captain (or other FO), from freaking out.  As long as it's not dumb or dangerous, then life is too short to worry about such bullshit.  If either of the others pilots are dickheads, then I may screw with them and do whatever they don't like, just for my entertainment.  1 degree off for the OCD types is pure entertainment.   

Yea, same here. There's a thousand different ways to fly the plane and I'm not so set in my ways that I can't adapt. You want me to do your technique? Fine.

I was told just last week to never use LVL CHG in a descent. Always use VERT SPD because LVL CHG is a violent maneuver for the FAs in the back. Never heard that before.

Also, set zeros in every MCP window before leaving the aircraft because... well just because.

[Buddy Spike]

35 minutes ago, torqued said:

Yea, same here. There's a thousand different ways to fly the plane and I'm not so set in my ways that I can't adapt. You want me to do your technique? Fine.

I was told just last week to never use LVL CHG in a descent. Always use VERT SPD because LVL CHG is a violent maneuver for the FAs in the back. Never heard that before.

Also, set zeros in every MCP window before leaving the aircraft because... well just because.

What airplane?

[Shamrock]

I hate this too. It’s always fun when you get a Captain that can’t go 30 seconds without talking about the SOP reach up and touch your panel. 

Roughly every 2 months I get an unexpected heading at cruise. I somehow survive with my super advanced skills of being able to turn the bug to the assigned heading. 

[gearhog]

36 minutes ago, Buddy Spike said:

What airplane?

737

[Buddy Spike]

4 minutes ago, torqued said:

737

That hasn't hit AA yet. LVL CHG when out of VNAV (usually on vectors) is normal.  And we usually don't do anything with the MCP when we leave. 

[HossHarris]

Same in the military. 

 

Currently flying a maddog. It will drop into heading hold or heading select unannounced (among other fun things). 

Having your heading bug in the general direction your going is useful when it goes crazy ivan.