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Airspeed bugs on standby altimeter

Started by Will, Tue, 7 Oct 2014 02:42

Will

Just curious, what sort of various airline (and/or Boeing) recommendations are there for the three airspeed bugs on the mechanical standby ASI? Both takeoff and landing configs, of course.

Thanks.
Will /Chicago /USA

Holger Wende

Hi,

Quite old question and I am actually wondering about the same since quite some time :) But I did not find an answer.
Normally I set the standby airspeed indicator bugs as follows, but I have no clue whether this is correct.

Takeoff: I position them at V1, Vr and V2.
Cruise: ? (I do not touch the bugs).
Approach: Speed limit below 10000 (i.e. typically 240), landing flap speed (flap25 or 30 as required), Vref.

Thanks, Holger

G-CIVA

Take Off

V1, V2 & VREF 30 + 80 (FLAPS UP SPD or MIN CLEAN SPD)

Cruise

Max Maneuvering SPD (Upper Yellow Hockey Stick on PDF SPD Tape)

Minimum Maneuvering Speed (Lower Yellow Hockey Stick on PDF SPD Tape)

Current VREF 30 as shown on the APP REF Page

Descent/App

VREF 30 or 25 + 80 (FLAPS UP SPD or MIN CLEAN SPD)

VREF 30 or 25 + 40

VREF 30 or 25 (dependent on Flap Selection)

My rationale is that should your primary Airspeed Instrument fail is that by using your STBY ASI & some of the INFO in the FMS you have all the info you need to get the aircraft CLEAN after departure & then 'dirty' again & correctly configured for a safe landing.

During the CRZ segment as the numbers change the three bugs are periodically changed i/e. at hourly fuel checks/WPT checks &/or FL changes - thus if things go wrong suddenly the 'ballpark info' is correct.

Not so sure how this would work with an ISFD?  Although the total failure of all the SPD Reference Systems must be a pretty rare event?
Steve Bell
aka The CC

United744

I wondered that with the ISFD too - it doesn't seem to know even basic limits.

John H Watson

Looking at some aircraft on airliners.net, some airlines don't even have bugs on their old type Standby Airspeed Indicators. Some have four bugs.

double-alpha

No recommandations from my Airbus FCOM...
Some pilots use bugs, some don't...

mark744

One company QRH for FMC Failure has the item:

14 Set Standby ASI bugs to VREF, VREF+20 kts,
VREF+40 kts, VREF+60 kts and VREF+80 kts for
approach and landing. Manoeuvring speeds are the
bugged speeds

( in preparation for the other FMC also failing )

There are therefore 5 Standby ASI bugs fitted to each aircraft in this company.

Hardy: it would be good to have 5 fitted to PSX or an option to do so, thanks

Hardy Heinlin

1 speed bug costs 500 bucks, thanks

mark744



Holger Wende

Thanks all for the replies.

Bugs for bucks  :D
In fact I started searching whether the term bucks is used for various currencies, not only $$$, hoping to find one with a cheap(er) exchange rate  ;) But quickly gave up, didn't want to trick Hardy   :-\

Regards, Holger

localiser

I never came across any recommendations for setting bugs on a conventional standby ASI in any company I've worked for. Using the bug function on electronic standby instruments has been discouraged though.

Like Double Alpha said, some pilots use them and some don't. If I'm on an aircraft that has them, honestly I don't set them for take off or landing. I think it's a bit too much detail for the day to day. I suppose you could set V1, V2 and up bug, but the takeoff speeds will normally be in your head anyway. However, at top of climb I think it's reasonable to have a quick look in the QRH or relevant FMC page and get the minimum clean speed/up bug/green dot (single bug) and Vref/Vapp (double bug) for the sector's take off weight. This way you know whatever your weight you're always covered relative to your clean and landing speeds and you always have them on there should the FMC fall over.

Jeroen D

Quote from: Holger Wende on Thu,  2 Nov 2017 12:12
Thanks all for the replies.

Bugs for bucks  :D
In fact I started searching whether the term bucks is used for various currencies, not only $$$, hoping to find one with a cheap(er) exchange rate  ;) But quickly gave up, didn't want to trick Hardy   :-\


The Indians use bucks for rupees (INR) sometimes.
Confused the hell out of me the first time I heard it.
So it looks we can have our additional bugs for the price of a decent cup of coffee then!

mark744

#13
So, two extra bugs for two cups of coffee
   
Deal  ;)


Quote from: localiser on Thu,  2 Nov 2017 23:06
I never came across any recommendations for setting bugs on a conventional standby ASI in any company I've worked for. ............................

BA  QRH  action for "FMC L/R"    is to set all 5   as stated in previous post
VREF,  VREF+20,  VREF+40, VREF+60, VREF+80   for flap manoeuvring speeds  in case of further FMC failure

localiser

@mark744....sure, I saw saw your earlier post. I was rounding out the picture. The airline you mentioned is a special case. As you probably know, they have blue lines of text in their FCOMs which add company inserted extra SOPs, in addition to the manufacturers' standard. Other companies have more, fewer or no modifications to their manuals. Depends on who you work for  :)

mark744

@localiser
Very true
BA obviously know best though  ;)

I don't know why every company doesn't just use Boeing manuals

Hardy Heinlin

There are many different opinions within the Boeing staff. There are many different opinions within an airline's staff. In total, there are many many different opinions. Which one is the best one, in your opinion? :-)

torrence

That's n! opinions, where n is the number of staff.  This can trend toward infinity.

Cheers
Torrence
Cheers
Torrence

Will

I took a ride in a UAL 737 sim a while back, with a UAL instructor. He said, very authoritatively, "United always uses a five-bug takeoff." I've always wondered what really meant. He didn't explain.

One of these days I want to say to some students in a sim "we always use a 57-bug takeoff. We bug 30 knots, then every 10 knots from 30 until V1, then V1, VR, V2-5, V2-3, V2, V2+3, V2+5, every flap retraction speed minus 5 and minus 3, plus Vmax minus 5, 10, and 15, and Vmin plus 5, 10, and 15, and Vso plus and minus 10, 5, and 3, and Vs1 plus and minus several speeds, Vno, and Vno-no, and Vno-no-no, and randomly 137 knots. And 287 knots. Plus the V speed closest to the serial number of the #2 engine."
Will /Chicago /USA

ScudRunner

I'd avoid flying on any aircraft with that many bugs.