Weather Radar Usage Boeing question

[stilton]

With all due respect to the real Engineers out there I do think the term has been a little corrupted and overused.


In the UK on a layover once I discovered my toilet was blocked, after calling the front desk they sent their (you guessed it) 'Engineer' with the requisite plunger.


He did do a good job though..

[Jaun Huw Nose]

Seconded Greybeard,maybe we should put it to the BALPA tech people to push the CAA?

[john_tullamarine]

I do think the term has been a little corrupted and overused.

Indeed, in Australia the only State which provides some control over the term (in this case for PEs) is Queensland via the Board of Professional Engineers.

Otherwise, generally the term is used for whatever you want it to represent ... I believe that the problem is quite widespread.

[PappyJ]

Multi-scan radar

I love this thing!

[PappyJ]

Your unblocker was probably a mechanic or a technician, not a licensed engineer, but he COULD have been.

I seriously doubt it! At a hotel! I believe the term would be "Janitor" or maybe "Plumber"

[forget]

Hugh amount of operating info here

http://rockwellcollins.com/content/pdf/pdf_3344.pdf

[M2dude]

Very good info, the WXR-2100 is a nice piece of kit.

[kijangnim]

Greetings

This picture was taken by the FO on a flight in the Far East, it is a typhon and they were entering it
two raisons, the first one they probably did not have a look at the weather chart, the second one both nd for Radar display were fully dimed, I am sure they will not forget again, this was a close call.

[M2dude]

I seriously doubt it! At a hotel! I believe the term would be "Janitor" or maybe "Plumber"

Oops. Sorry PappyJ, I'll RTFQ next time. I'm off to unblock my toilet.

[NSEU]

In the UK on a layover once I discovered my toilet was blocked, after calling the front desk they sent their (you guessed it) 'Engineer' with the requisite plunger.

Maintenance Engineers are multi-talented Or rather, the airline, in the name of efficiency, have highly educated people cleaning ovens and trash compactors, washing windscreens, greasing nipples , removing chewing gum from carpet, etc.

[BigGrumpyAlien]

Well ladies and gents, thank you for the posts......I have made some further ground and post the following. It is by no means definitive and is a hopefully brief overview with some interesting points....

I knew I had covered some of the stuff but it has been good to refresh some of those old brain cells....

It has gone some way to answering my questions.. I have produced it below and hope that it is of help to some......



The GPWS provides alerts based on radio altitude and combinations of barometric altitude, airspeed, glide slope deviation, and airplane configuration and is operative between 30 ft and 2450 ft RA. The alerts are for:

1. Excessive descent rate
2. Excessive terrain closure rate a. With Flaps NOT in landing position. b. With Flaps IN a landing position.
   
3. Altitude loss after takeoff or go-around
4. Unsafe terrain clearance when not in the landing configuration a. Landing Gear NOT down AND Flaps NOT in landing position. b. Landing Gear NOT down OR Flaps not in landing position.
5. Excessive deviation below an ILS glide slope
6. Altitude Callouts
7. Windshear Detection

The GPWS takes Input from:

• Air Data System
• IRS
• ILS
• RAD ALT

For Look Ahead Terrain Alerts additional Inputs from;

• NON Pegasus FMC
• Pegasus GPS

Notes
GPWS

• Monitors Terrain using an INTERNAL WORLDWIDE DATABASE. It does not account for manmade objects.
• Terrain display is generated using a build in ‘sweep’ on the display. It IS NOT a radar display. This display is computer generated from the database in the GPWS and correlated to GPS position.
• Altitude callouts are made based on the setting of the Captains Rad Alt.
• Does not provide an alert for flight toward vertically sheer terrain or slow descents into terrain while in the landing configuration.
• Uses WGS-84 data(be aware not all countries are WGS-84 compliant)

Terrain ahead of the airplane may exceed available climb performance. A ground proximity caution or warning does not guarantee terrain clearance.

WINDSHEAR
Can be more easily described by breaking it down into two distinct parts.

1. Windshear
2. Predictive Windshear.

Windshear
Windshear alerts are available during takeoff, approach and landing. GPWS provides a warning when the airplane is in a windshear.

• Excessive windshear at the current airplane position detected by GPWS.
• Enabled below 1,500 feet Radio Altitude.

GPWS Windshear detection begins at rotation.


Predictive Windshear

Weather radar provides “predictive windshear alerts” for excessive windshear ahead of the airplane and these are annunciated on the HSI.

The weather radar

• Uses radar imaging to detect disturbed air prior to entering a windshear.
• Provides windshear alerts for windshear events containing some level of moisture or particulate matter.
• Detects microbursts and other windshears with similar characteristics.
• Does not provide alerting for all types of windshear.

Note: The automatic function of the GPWS provides “pop-up” displays for predictive windshear and terrain. If neither pilot has weather radar on, and a predictive windshear caution or warning occurs, the weather display and predictive windshear symbol automatically show on the HSI. If neither pilot has terrain display on, and a look-ahead terrain caution or warning occurs, the terrain display will automatically show on the HSI.

Warnings(Predictive)

Windshear

• Windshear close to and directly ahead of the airplane detected by the weather radar.
• Enabled during takeoff, below 1,200 feet Radio Altitude.

Go Around Windshear Ahead

• Windshear within 1.5 miles and directly ahead of the airplane detected by the weather radar.
• Enabled during approach, below 1,200 feet Radio Altitude.

Monitor Radar Display

• Windshear within 3 miles and ahead of the airplane detected by the weather radar.
• Enabled during takeoff and approach, below 1,200 feet Radio Altitude.

The weather radar automatically begins scanning for windshear when:

• Thrust levers set for takeoff or
• In flight below 2,300 feet Radio Altitude (predictive windshear alerts are issued below 1,200 feet Radio Altitude).

Alerts are available approximately 12 seconds after the weather radar begins scanning for windshear. Predictive windshear alerts can be enabled prior to takeoff by pushing the EFIS control panel WXR switch.

If windshear is not detected, weather radar returns show only after pushing the EFIS control panel WXR switch.


During takeoff and landing,

• New predictive windshear caution alerts are inhibited between 80 knots and 400 feet Radio Altitude.
• New warning alerts between 100 knots and 50 feet Radio Altitude.

These inhibits do not remove existing predictive windshear alerts.

[kijangnim]

Greetings
Water in Liquid form has to be present, so on wet snow you will have Predictive WS, Wet Hail....

GPWS gets its input from Number 1 side (Captain's side) so radio altimeter 1 fail you will loose some functions, when on the ground, swapping Radio altimeters will enable GPWS to be back watching

[forget]

........ swapping Radio altimeters will enable GPWS to be back watching.

Not necessarily. There's more to RadAlts than a black box. Degraded antennas etc etc.

[kijangnim]

radio altimeter 1 fail where is antenna mentioned, I really dont understand why there is always someone reading things that are not written...

[forget]

Someone else explain, please. My English is, apparently, limited.