longhaul67
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737 Cockpit Instrument Question

Sun Mar 18, 2007 1:08 am

The 733 had roll out and first flight in 1984. I believe at the time all of the cockpit instruments were the old fashioned analogue ones, and not electronic/digital indicators.
But browsing through the a.net photo database I see that 734s and even some 735s have the same analogue indicators as the 733. These models had first flight/roll out in the late 80s.

When did Boeing start digitalizing 737 cockpit indicators?
Did Boeing lag behind Airbus at the time in modernising their cockpits?
 
EGBJ
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 1:17 am

Not sure when Boeing started to digitilize things but some airlines actually chose to not have the updated cockpit (EFIS displays etc.) to maintain commonality with their older 733's and 732's. WN took this option I believe so the same pilots could fly both.
 
IAHFLYR
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 3:11 am

CO had a few 733's that were EFIS but primarily their 735's ushered in EFIS into their B73X fleet. The 735's came along into the CO fleet around 1993 time frame. The 733's with EFIS for CO have left the fleet from what I was told due to the lease agreements they had with those.

I doubt any of the US 734's had EFIS and I know the WN 735's were and I believe still all round dial, UA's 735's IIRC are EFIS as well.
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OPNLguy
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 3:22 am

Quoting Iahflyr (Reply 2):
I know the WN 735's were and I believe still all round dial,

All 194 of the -300s and all 25 of the -500s are "round-dial". There have been rumors that some will get an upgrade to the flat panels that the -700s use, but nothing definite.
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Curmudgeon
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 3:46 am

Australian Airlines, which later merged into Qantas, had EFIS in all of their 733's. The first was delivered in 1986.
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wing
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 3:57 am

Quoting LongHaul67 (Thread starter):
Did Boeing lag behind Airbus at the time in modernising their cockpits?

Around the same time Boeing made the "great innovation of digital engine instruments" the rivaling Airbus made the A320.You make the comparison.
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Jetlagged
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 5:38 am

Quoting Wing (Reply 5):
Around the same time Boeing made the "great innovation of digital engine instruments" the rivaling Airbus made the A320.You make the comparison.

Not exactly true. Boeing first put digital engine instruments on EICAS on the 767 (first flight 1981) and 757 (1982). Both had EFIS too. The contemporary Airbus A310 also had EFIS but retained round dial engine instruments. EICAS was a big step forward conceptually.

Of course the A320 completely revolutionised flightdeck design (all glass cockpit). Fokker had an all glass cockpit in service soon afterwards (Fokker 100). Boeing weren't far behind Airbus with their 747-400.
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longhaul67
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 9:35 am

I guess whats puzzling me is that the 734 and 735 both had roll out and first flight in the late 80s, so they should have digital indicators from launch. I suppose commonality is the key word here, not every airliner saw the immediate benefit.

At the time I remember there was a lot of controversy about digital cockpits, most of the pilots were trained using standard analogue indicators. The Air Inter accident comes to mind where the pilots didnt fully understand how modern digital instruments functioned
 
KELPkid
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 9:54 am

As I understand it,

Aren't the "steam gauges" in the 737-300 through -500 actually electronic instruments? (Meaning, they aren't actually direct-measuring instruments as they would be in the instrument panel of most GA planes, but rather the needles are commanded to move electronically)  Wink Correct me if I'm wrong, but I could've sworn I read this somewhere...
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OPNLguy
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 3:00 pm

Quoting KELPkid (Reply 8):
Aren't the "steam gauges" in the 737-300 through -500 actually electronic instruments?

Ref: http://www.airliners.net/open.file/0987653/L/

I was always under the impression that they were purely mechanical, with the possible exception the engine indications (N1, N2, F/F and EGT) since those also incorporated yellow-ish/green digital readouts in addition to a pointer.

The original fuel quantity indicators looked mechanical, and they later started coming from Boeing with Simmons LCD-style FQIs. Also, the old IVSIs were mechanical, IIRC, but were replaced by units that incorporated the TCAS displays, so all that would have to be electronic.
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fr8mech
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 9:42 pm

The indicators were mechanical but were fed information from transmitters from their respective systems. More modern aircraft feed the information through a computer to convert from analog to digital.

The only transport aircraft I've ever worked on that had direct read indicators was (is) the DC8 and that is manifold pressure indicator.
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RE: 737 Cockpit Instrument Question

Sun Mar 18, 2007 11:41 pm

The 737 Classic is basically an analogue aircraft, so the scope for fitting an all digital cockpit was limited, given the technology of the time. Originally it didn't have EFIS either, though the FMS was standard. The 737NG re-design allowed a more extensive cockpit re-vamp.

The 737 digital engine displays use exactly the same transducer inputs as the round dials. Only the presentation is digital. The biggest difference was that mechanical pointers were replaced by LED segments. Digital readouts were unchanged. Hydraulic gauges were replaced by simple digits. Some would argue that the electronic engine displays added nothing, but subtracted some of the dynamic cues the traditional round dials give. There's certainly a loss of pointer resolution, and the secondary instruments are not as clear. The display format was a factor in the Kegworth accident.

In their day, the 737 Classic round dial instruments were a step forward, as they had dot matrix rolling digits. The engine instruments originally designed for the 757/767 had non-rolling LCD digits.

Quoting LongHaul67 (Reply 7):
I guess whats puzzling me is that the 734 and 735 both had roll out and first flight in the late 80s, so they should have digital indicators from launch.

The digital indicators quickly became the standard fit, but round dials were still available as an option for commonality.

Quoting KELPkid (Reply 8):
Aren't the "steam gauges" in the 737-300 through -500 actually electronic instruments?

They certainly weren't like the engine instruments on the older 737-200's, exactly like those on the 727, very simple instrumentation. 737-200adv had more sophisticated electronic indicators, but no digital readouts, unlike the 737-300.
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Tristarsteve
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RE: 737 Cockpit Instrument Question

Mon Mar 19, 2007 12:16 am

Quoting Jetlagged (Reply 11):
The digital indicators quickly became the standard fit, but round dials were still available as an option for commonality

BA and KL both specified round mechanical engine instruments on their B737-400, as both were ordered just after the British Midland crash at Kegworth which was blamed on misreading the digital display.
Later on we had some seconhand B734 with digital instruments and I must admit I never liked them.
I always wondered why Boeing didnt put the B757 type EICAS on the B734? It was much easier to read.
 
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Jetlagged
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RE: 737 Cockpit Instrument Question

Mon Mar 19, 2007 1:22 am

Quoting TristarSteve (Reply 12):
I always wondered why Boeing didnt put the B757 type EICAS on the B734? It was much easier to read.

I suppose because the 757 EICAS requires a lot of information on ARINC 429 busses, not present on the 737 Classic. They would have had to have added ARINC transmitters for the engine parameters as a minimum. Developing a reduced form of EICAS for the 737 was probably not thought worth the effort. The solution they adopted for the 737 NG still doesn't include the Caution and Advisory part of EICAS, so it is really an EIS.  Wink I suspect that was more for the common type rating than anything else, because a true EICAS would certainly have been possible. Some discrete and status info is presented though.
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wing
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RE: 737 Cockpit Instrument Question

Mon Mar 19, 2007 2:32 am

Quoting Jetlagged (Reply 6):
Not exactly true. Boeing first put digital engine instruments on EICAS on the 767 (first flight 1981) and 757 (1982). Both had EFIS too. The contemporary Airbus A310 also had EFIS but retained round dial engine instruments. EICAS was a big step forward conceptually.

The question was about the 737 thats why I mentioned the A320.One can not compare the 737s in the 80s and the A320s in the 80s.A320 was light years away from the 737-200,years away from the 737400 and still away from the 737NG from the pilots point of view.
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KELPkid
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RE: 737 Cockpit Instrument Question

Mon Mar 19, 2007 4:07 am

Quoting Fr8mech (Reply 10):
The only transport aircraft I've ever worked on that had direct read indicators was (is) the DC8 and that is manifold pressure indicator.

Do you mean EPR? I don't know what manifold you'd be measuring the pressure of in a DC-8  Wink
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fr8mech
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RE: 737 Cockpit Instrument Question

Mon Mar 19, 2007 6:56 am

Quoting KELPkid (Reply 15):
I don't know what manifold you'd be measuring the pressure of in a DC-8

Pneumatic manifold.
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Jetlagged
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RE: 737 Cockpit Instrument Question

Mon Mar 19, 2007 11:24 pm

Quoting Wing (Reply 14):
The question was about the 737 thats why I mentioned the A320.One can not compare the 737s in the 80s and the A320s in the 80s.A320 was light years away from the 737-200,years away from the 737400 and still away from the 737NG from the pilots point of view.

Sorry, but with great respect, the instrumentation on a derivative aircraft (737 Classic) compared to a clean sheet of paper design (A320) is hardly fair and does not show that Airbus was significantly ahead of Boeing overall. I agree that the 737 Classic flightdeck is pre-historic compared to the A320 but the question was:

Quoting LongHaul67 (Thread starter):
Did Boeing lag behind Airbus at the time in modernising their cockpits?

Note, Boeing and Airbus cockpits in general, not the 737 in particular. You answered:

Quoting Wing (Reply 5):
Around the same time Boeing made the "great innovation of digital engine instruments" the rivaling Airbus made the A320.You make the comparison.

I merely pointed out that Boeing had put digital engine instruments on their 767 (clean sheet of paper) while Airbus did not on the A310 (derivative). The "great innovation of digital engine instruments" was not a claim Boeing made for the 737 that I remember. Airbus were certainly ahead, but maybe only by a year or so in terms of new designs, not derivatives.
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Steelyman
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RE: 737 Cockpit Instrument Question

Tue Mar 20, 2007 4:38 am

As OPNLguy said before, some airliners got the upgrade of their avionics displays into flat panels. As an example I could give Virgin Express (TV/VEX). I'm not sure which one was, but for sure that 2 of the following have flat panels: OOVBR /OOVES/OOVEK/OOVEP.
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SansVGs
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RE: 737 Cockpit Instrument Question

Tue Mar 20, 2007 4:52 am

I recall some of the really late model 737-200's flown by Western and later by Delta actually had the same "baby EFIS" available on 3/4/5 series.

As an aside US Airways ordered all "hard ball" planes in 3/4 series. For what reason I don't know.
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Valkyrie01
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RE: 737 Cockpit Instrument Question

Wed Mar 21, 2007 10:18 pm

Quoting Iahflyr (Reply 2):
I doubt any of the US 734's had EFIS

They had EFIS
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Jetlagged
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RE: 737 Cockpit Instrument Question

Wed Mar 21, 2007 10:38 pm

Quoting SansVGs (Reply 19):
As an aside US Airways ordered all "hard ball" planes in 3/4 series. For what reason I don't know.

Probably cost and spares commonality. EFIS display units (and the associated symbol generators) are expensive items. If you have mixed EFIS and clockwork aircraft you would need to hold spares for both. With an all clockwork (or all EFIS) fleet you may might be able to hold fewer spares overall. Spares on the shelf do not make money for the airline. Also on the 737 the EADI and EHSI are not interchangeable so no savings there.
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Starlionblue
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RE: 737 Cockpit Instrument Question

Wed Mar 21, 2007 10:43 pm

Quoting LongHaul67 (Reply 7):
I guess whats puzzling me is that the 734 and 735 both had roll out and first flight in the late 80s, so they should have digital indicators from launch. I suppose commonality is the key word here, not every airliner saw the immediate benefit.

At the time I remember there was a lot of controversy about digital cockpits, most of the pilots were trained using standard analogue indicators. The Air Inter accident comes to mind where the pilots didnt fully understand how modern digital instruments functioned

As you say, commonality.

Quoting KELPkid (Reply 8):
Aren't the "steam gauges" in the 737-300 through -500 actually electronic instruments? (Meaning, they aren't actually direct-measuring instruments as they would be in the instrument panel of most GA planes, but rather the needles are commanded to move electronically)

Depending on version yes. The instruments are round dials but instead of a needle they have lights that illuminate and move around in a needle like fashion.

Quoting TristarSteve (Reply 12):

BA and KL both specified round mechanical engine instruments on their B737-400, as both were ordered just after the British Midland crash at Kegworth which was blamed on misreading the digital display.

That accident was a big wake-up call. The wrong engine was shut down because the pilot not flying misread the engine instruments. They are small, all look alike, and are not entirely intuitively organized. IIRC, the pilot not flying changed his mind when reporting which engine was malfunctioning.


Here's a pic showing the digital needles:

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Photo © Florian Joachim

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Jetlagged
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RE: 737 Cockpit Instrument Question

Wed Mar 21, 2007 11:12 pm

Quoting LongHaul67 (Reply 7):
The Air Inter accident comes to mind where the pilots didnt fully understand how modern digital instruments functioned

It wasn't the crew's fault that the autopilot FPA/VS display was confusing or that GPWS was not mandatory in France at the time. Approach flight path angle (-3 degrees) would have been displayed on the autopilot FCU as

- 3.0

and the -3000 ft/min vertical speed they actually had selected was displayed as

- 3 0

Only a decimal point to indicate the difference. They had about four times the descent rate they wanted. They should have checked that FPA was selected, of course . GPWS might have warned them in time. Add to that everybody "knew" the A320 could not be crashed, the computers would see to that. Airbus subsequently added two more zeros to the VS display on the FCU.
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