Is Radar Altimeter working?

BIG, double-deck, four-engine, medium to long range, high altitude, high speed, commercial transport airplane
new reply
Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Is Radar Altimeter working?

Post by Avio »

Noticed the radar altimeter only function when below 4000 ft MSL. Above that, no matter how close to a mountain range top, it just would not show any AGL reading. Is that right?

User avatar
Jacques
Senior Master Sergeant
Posts: 2376
Joined: 26 Jun 2011, 17:54
Location: West Coast, USA

Re: Is Radar Altimeter working?

Post by Jacques »

You need to make sure that the pilot’s and co-pilot’s radio altimeters are identical in their settings for this to function correctly. Beyond that I’ll defer to TreeTops or another pilot who is still flying the Stratocruiser.

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Is Radar Altimeter working?

Post by TreeTops »

The captain and first officer's radio altimeter's are the same instrument type and independant.
Bottom left is the on/off button, top right is the range 400/4000 button with 400 or 4000ft maximum height reading. Mostly on approach you would use the 400 setting since you get the most needle movement for altitude change closer to the landing phase. If the airport was surrounded by terrain the pilots would have briefed the use of 4000 ft setting prior to the final approach. Perhaps the pilot flying would have a 400 setting (landing assistance) and the pilot not flying would have the 4000 setting (bigger picture).

The navigator radar altimeter is different.
Bottom left is the on/off button, top left is the range 5000/50000 switch with 50000ft maximum height reading.
Maximum reading at the 5000 setting appears to be 0 when above 5000ft. Switch to 50000 when above 5000 ft.
Having the ability to read ground height would assist the navigator mark the passage of the flight across terrain with the absence of all over nav sources.

I just did a test slewing from the coast across mountains.
The pilot and copilot do not need to have the range set the same, as they work independly.
Being radar, they are independant of the barometric altimeters.

Hope this is helpful
Cheers
Trev

User avatar
Jacques
Senior Master Sergeant
Posts: 2376
Joined: 26 Jun 2011, 17:54
Location: West Coast, USA

Re: Is Radar Altimeter working?

Post by Jacques »

Its kind of like one person says to hop on one foot...so everyone starts hopping on one foot. :lol:
Thanks for the correction, Trev!

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Is Radar Altimeter working?

Post by TreeTops »

Thats ok mate. I know you have helped me out plenty of times. 8)
Cheers
Trev

Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Re: Is Radar Altimeter working?

Post by Avio »

Thanks TreeTops.

What I did previously was I set it to 4,000 ft, and remember flying at 10,000 + ft over some mountains. Height above mountains was just a 1000 or 2000 ft or so, but yet this AGL was not registered and shown on the gauge. I did switch on the unit.

It did work correctly though when the plane was below 4000 ft MSL. Is there something else I need to do?

Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Re: Is Radar Altimeter working?

Post by Avio »

By the way, there isn't any DME readout. How does one shoot a VOR approach or conduct IFR flight without such?

Would like to do some IFR work with this one.

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Is Radar Altimeter working?

Post by TreeTops »

Without DME, the clock is your friend.
Fly out from the beacon, perform the reversal and hey presto, you are on the approach.
Cheers
Trev

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Is Radar Altimeter working?

Post by TreeTops »

Avio wrote: 08 Jul 2020, 01:16 Thanks TreeTops.

What I did previously was I set it to 4,000 ft, and remember flying at 10,000 + ft over some mountains. Height above mountains was just a 1000 or 2000 ft or so, but yet this AGL was not registered and shown on the gauge. I did switch on the unit.

It did work correctly though when the plane was below 4000 ft MSL. Is there something else I need to do?
Where were you flying? I want to replicate what you were doing.
Cheers
Trev

Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Re: Is Radar Altimeter working?

Post by Avio »

I think it was mountain ranges near KEGE

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Is Radar Altimeter working?

Post by TreeTops »

I have just setup at KEGE and slew south at 13500ft. All 3 radar indicators were indicating exactly as they should as they past over the mountains.
The 2 pilots were on 4000 ft, the navigator was on 5000 ft.
Cheers
Trev

Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Re: Is Radar Altimeter working?

Post by Avio »

That is strange ... would have to test again.

One more question ... the rudder is tied to steering like normal plane? I find it much easier turning with rudder peddals then turning the side wheel.

Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Re: Is Radar Altimeter working?

Post by Avio »

About navigation, wonder how they did it in IMC back in those days, especially without DME ! Would love to navigate realistically.

TreeTops
Master Sergeant
Posts: 1086
Joined: 07 Apr 2010, 06:13

Re: Is Radar Altimeter working?

Post by TreeTops »

For the sim you can use the rudder for taxi steering. I have a separate joystick setup just for this job.
Modern jets fly to the intersection of ILS approaches with GPS. I guess back in the day all they had was the single nav station. Once they flew over the nav station they would have performed manouvers to fly back over the nav station outbound on the correct heading such that they could do a standard course reversal after X minutes and then would be positioned at the start of an approach.
Remove precision from your mindset (of the GPS kind) and just follow needles, course, speed and time. An NDB approach plate is perfect for practicing this type of flying.
When flying remote and using the sextant, knowing your location within 5nm is plenty accurate enough to get you to a nav beacon 2000nm away.
Cheers
Trev

Avio
Staff Sergeant
Posts: 392
Joined: 20 Jan 2009, 01:59

Re: Is Radar Altimeter working?

Post by Avio »

Haha and throw in some wind and clouds and it is amazing they could get from points to points long distance !

new reply

Return to “Boeing 377 Stratocruiser”

Who is online

Users browsing this forum: Google [Bot] and 4 guests