So I was looking at pictures and came across the picture below:

View Large View Medium

Photo © Michael Carter


And so I have a simple question that im sure can be easily answered by someone. What are static ports and what are they used for? So that's it, simple.

Thanks in advance

Tom

They are an opening to get outside air pressure to flight insturments. In large airliners, they would feed to an air/data computer that would take this and compute altitude, vertical speed, and use it in connection with ram air from the pitot tube to calculate airspeed.

In smaller aircraft, it may just be connected via rubber hose to the back of the altimeter, vertical speed indicator, and airspeed indicator.

Let's see if we can answer this in less than 100 posts...

Static ports provide a means to measure static pressure of the ambient air for use in air data instrumentation such as altimeters, vertical speed indicators, airspeed indicators (in conjuction with pitot pressure) and as refererence for pressurization and any other system that may require "static" pressure such as Flight Data Recorders.

Static ports are perpendicular to the airflow to avoid any error being introduced by variations in airspeed.

To add, your airspeed indicator and/or machmeter use BOTH pitot and static pressure. By measuring the difference in pressure between the two, you get your airspeed. OTOH, your VSI and altimeter only use static pressure.

Looks like Airplay beat me to it 

Thank you all, you have all done a very good job answering my question. Its greatly appreciated.

Thanks

Tom

Question to the experts: Is the static port subject to the Bernoulli effect, that means, is the pressure measured dependent on the airspeed? Should be in theory. In other works, is the altimeter readout dependent on the airspeed?

Regards and happy New Year,

OE-LDA

No, the static ports (as they are flush with the fuselage) will not suffer from the Bernoulli effect. And the positioning of the ports are usually positioned in areas where the boundary layer of air tends to be very stable, which lessens the effect of the static ports being hampered by turbulent flow.

A lot of effort is made to find locations for the static ports where they will measure as close to ambient static air pressure as possible, regardless of airspeed, angle of attack, slip angle and other unwanted disturbing factors.

This means they will be on areas where the air is largely unaccelerated from freestream velocity. Bernoulli will thus not be a large factor.

Of course, it is never perfect. That's why you have Indicated Air Speed and Calibrated Air Speed. What you see on the instrument might not be the actual airspeed, especially at high angles of attack and so on.

Cheers,
Fred

Pitot and Static system will be a thing of the past in 10 year years. Jet fighter technology is now making its way into commercial airlines and you will begin to see Intergrated Mutli-Functional Probes (IMFP). This system incorporates a Micro Air Data Computer, AOA probe, OAT probe, altitude and airspeed all incorporated into one probe, with no pitot or static system. This will greatly reduce wieght and down times. No more pitot/staic checks.

TechRep

Techrep- I think you are overly optimistic. Aviation can be very slow to adopt new technology sometimes. Also, IMHO, systems that combine many components into one unit result in one extremely expensive and complicated part. The outcome isn`t always an improvement. Anyway, given that aircraft from the 1940s are still in commercial service around the world, the old pitot/static system is here to stay!  

Techrep,
got a reference for that. I'd like to read up on it. Who makes'em, what aircraft and so on?

Cheers,
Fred

Let me clarify, all new aircraft manufactured 10 years from now will have this system or equivalent.

The IMFP is made by Honeywell and can be fitted to the new Primus Epic Avionics Suite or retrofitted to other avionic systems. The Dornier 728 was supposed to be the first commercial aircraft to have the probe but that project cratered.

Almost all major avionic manufactures are producing this probe for military use but Honeywell is now offering it for commercial use as well.

http://www.avionics-specialties.com/Products/IMFP/IMFP_Main.htm#Integration

Techrep

Techrep- I wonder how they will deal with the backup issue? As it stands, a completely mechanical, standard old ASI and ALT are common for backups. There are many electronic standby instruments out now, but unless I'm mistaken they too are plumbed the old fashioned way.
PS: Airplay, only 87 to go!  

[Edited 2004-01-02 22:54:38]

Let me clarify, all new aircraft manufactured 10 years from now will have this system or equivalent.

Not likely....you can put an entire new avionics suite in a Baron for what this probe costs. And the dependancy of electrical power and susceptibility to failure will preclude total system replacement.

Pitot and Static system will be a thing of the past in 10 year years.

This is just another manifestation of the pitot-static system.

This will greatly reduce wieght and down times.

Why do you say that? You are introducing a highly integrated multifunction device. Any single failure or suspected failure will cause this (likely) very expensive unit to be replaced more often than required as is the case with similar integrated components. This sort of modularization is good for military applications but has proven to be a financial nightmare for airliners.

No more pitot/staic checks.

Are you suggesting that air data calibration checks will no longer be neccessary?

The IMFP is made by Honeywell

Are you sure about that? I think Honeywell only makes the air data sensor inside.

Micro Air Data Computer

You have to be careful when you use the term "micro air data computer". An MADC is an acronym that typially describes a precision unit capable of meeting RVSM contraints. Not neccessarily a small or "micro" unit. "Miniature" might be the word you're looking for.

It is my belief that the Pitot/Static systems now ubiquitous in modern large commercial transport aircraft (30 Seat +) will experience a complete evolution in the next 5-10 years. The technology is already starting to emerge; "Military-Type" Integrated Multi-Functional Probes (IMFP) are now offered for large commercial transport aircraft with integrated flight decks.

These IMFP's are a manifestation or miniaturized version of the Pitot/Static system but nonetheless they are a huge technology progression. These IMFP’s do not require the system checks found in conventional Pitot/Static systems but have their own Built in Fault Awareness. The IMFP/ADS System coupled with an Integrated Flight deck may look something like this:

Primary air data system
- Three remote mounted multifunction probes including AOA
- Air data application (ADA) software on a DEOS processor module in the MAU
- Interface to the dual TAT (Airframe) via part of an I/O module in the MAU.
The standby air data system shall consist of:
- One combined altimeter/airspeed indicator system
- An Integrated Multifunction Probe (IMFP)

The IMFP’s shall sense and transmit static and total pressure to the ADA on an ARINC 429 bus to an MAU I/O module. The pressure signals from the IMFPs along with TAT, AOA, baro and discrete information shall be used to calculate the air data parameters. (Self diagnostic in other words)

In general, this ADS shall meet or exceed performance specifications defined by applicable ARINC specifications (ARINC 706) and regulatory TSOs (TSO-C106 and TSO-C88a) for traditional ADCs.

Conclusion

Since error correction and error reporting are real-time, the integrated cockpit can easily find/report unit failure. Less downtime/Less Manpower Consumption/Less Hassle.

Airplay, I am in fact saying that this system requires NO manual system calibration/re-certification found in the conventional Pitot/Static system. The units Built in Self Test Equipment (BITE), nullifies this requirement. Other than daily Power on self tests and yearly combined system testing are required. The requirements of FAR 91.411 will be greatly reduced if not nullified.

Honeywell does produce a complete IMFP and this probe is available for use with the Epic Primus avionics Suite. However the ADS system Embraer is using does not include the IMFP. To Date only the Dornier 728 was offering this LRU for installation to my knowledge.

I can’t emphasize enough the weight savings, lower production costs and long term cost benefits of this ADS.

Carbon fiber brakes and EFIS Cockpits, once considered military use only and to cost prohibited, eventually made there way into Commercial aviation, so too will this system.

I hope I was more specific with my wording this time, thanks for the great input Airplay.

TechRep