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How Did Pilots Get By Without An FMC?  
User currently offlineGerry From Australia, joined Jul 1999, 241 posts, RR: 0
Posted (10 years 6 months 1 week 3 days 23 hours ago) and read 4113 times:

I know that before the magic boxes arrived in modern heavies that INS was used but how did that work exactly? Did you have to programme in waypoints only using Latitude and Longitude or could you put in VORs and NDBs? Checking the flight plan must have been a painstaking, slow and potentially risky procedure. When I look at an older DC10 or 727 panel you wonder how the hell they ever arrived any where with any accuracy particularly over longer routes over water or where there were very few navaids? Can anyone enlighten me?

20 replies: All unread, jump to last
 
User currently offlineShaun3000 From United States of America, joined Mar 2002, 445 posts, RR: 0
Reply 1, posted (10 years 6 months 1 week 3 days 19 hours ago) and read 4024 times:

The INS systems used in airliners is virtually identical to the ones used by Apollo astronauts to get to the moon.

Apparantly, they are EXTREMELY accurate.


User currently offlineAAR90 From United States of America, joined Jan 2000, 3465 posts, RR: 47
Reply 2, posted (10 years 6 months 1 week 3 days 18 hours ago) and read 3971 times:

Did you have to programme in waypoints only using Latitude and Longitude or could you put in VORs and NDBs?

Start by understanding that INS is not "gone" just hidden behind the fancy computer called FMS. Yes, the early INS' did not have large databases full of preprogrammed information. You aligned the platforms and entered the LAT/LONG of each waypoint by hand... labor intensive and error prone.

Checking the flight plan must have been a painstaking, slow and potentially risky procedure.

Yes. Still is slow today, just not nearly as slow.

When I look at an older DC10 or 727 panel you wonder how the hell they ever arrived any where with any accuracy particularly over longer routes over water or where there were very few navaids?

If you performed a good alignment you would see error of no more than 2nm/hour. A 10 hour flight would have you no more than 20 miles or so off course. Certainly close enough to pick up radio NAVAIDs for the terminal portion of the flight. Until the advent of FMS' most INS equipment was only certified for use "enroute." You were required to use radio NAVAIDs as primary navigation for departures and arrivals.



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineUadc8contrail From United States of America, joined Sep 2003, 1782 posts, RR: 9
Reply 3, posted (10 years 6 months 1 week 3 days 18 hours ago) and read 3963 times:

early days it was called adf......something a/bus does not have on their a/c anymore


bus driver.......move that bus:)
User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4488 posts, RR: 21
Reply 4, posted (10 years 6 months 1 week 3 days 17 hours ago) and read 3895 times:

early days it was called adf......something a/bus does not have on their a/c anymore

I don't believe that's true....



I got my head checked--by a jumbo jet
User currently offlineBuckfifty From Canada, joined Oct 2001, 1316 posts, RR: 20
Reply 5, posted (10 years 6 months 1 week 3 days 17 hours ago) and read 3873 times:

If I remember correctly, it was because the crew incorrectly input the waypoints in the INS that caused KE007 to stray off course, and ultimately get shot down by the Soviet interceptors back in '83.

Had to do manual INS transport error calculations for my ATPL's. Pain in the arse. Also had to do the INS displacement error calculations too. I don't know why in this day and age anyone would need to do these calculations still, but hey, it was interesting to learn.

early days it was called adf......something a/bus does not have on their a/c anymore

ADF for the NDB's? Sure Airbuses still use NDB information, they just don't autotune them in managed modes, that's all. But the INS and the ADF are not related systems, if you're implying that.


User currently offlineRiddlePilot215 From United States of America, joined Oct 2003, 318 posts, RR: 0
Reply 6, posted (10 years 6 months 1 week 3 days 17 hours ago) and read 3842 times:
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Besides the fact that NDB/ADF's are quite possibly the most inaccurate form of navigation known to man, besides stellar navigation....


God is good, all the time. All the time, God is good.
User currently offlineDeltaGuy From , joined Dec 1969, posts, RR:
Reply 7, posted (10 years 6 months 1 week 3 days 17 hours ago) and read 3837 times:

Still the way it's done in the Boeing 737-200 and 727-200....VOR's and radials....sorta like you do in your cessna. The B732 has almost nothing in the way of modern automation, save for the standard autopilot functions (VOR, ALT, SPD, etc etc etc etc)...no INS or FMS. Pilots have to manually tune the VOR and intercept the inbound course...sounds like fun for a 4 hour trip right? Sure is  Big grin

In spite of all this glass...there's still some old fashioned dials and gages.  Big thumbs up

DeltaGuy


User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4488 posts, RR: 21
Reply 8, posted (10 years 6 months 1 week 3 days 17 hours ago) and read 3838 times:

Besides the fact that NDB/ADF's are quite possibly the most inaccurate form of navigation known to man, besides stellar navigation....

As I was told back in my early instrument training days:

It's that inaccurate piece of junk that will bring you home when all your fancy gadgets fail.

Shoot, at the very least, you can listen to the ball games (or gospel music) while futzing around in the air  Smile/happy/getting dizzy

May be a shred of truth to that  Big grin



I got my head checked--by a jumbo jet
User currently offlinePositive rate From Australia, joined Sep 2001, 2143 posts, RR: 1
Reply 9, posted (10 years 6 months 1 week 3 days 17 hours ago) and read 3829 times:

Regarding the old cockpits on 727's,DC-10's,L1011's and 747 classics- how did the pilots know exactly where they were at all times of the flight? These days the track is displayed on the EHSI with a magenta line representing the active track and all the waypoints are displayed along with the ETA for that particular waypoint. Back in the days of the "steam driven cockpit" did the pilots have to work all this stuff out manually? And could the track be displayed or not?


Thanks


User currently offlineUadc8contrail From United States of America, joined Sep 2003, 1782 posts, RR: 9
Reply 10, posted (10 years 6 months 1 week 3 days 16 hours ago) and read 3807 times:

jbird,
there are no ADFs on the bus............at least the ual a/bus



bus driver.......move that bus:)
User currently offlineJBirdAV8r From United States of America, joined Jun 2001, 4488 posts, RR: 21
Reply 11, posted (10 years 6 months 1 week 3 days 14 hours ago) and read 3747 times:

UaDC8...

Guess you might just be right....what a concept!!  Laugh out loud

This pic from mid-2002 shows the ND switches on the glareshield with ADF selectable:


View Large View Medium
Click here for bigger photo!

Photo © Nicky van Hassel



However, these two from slightly later seem to show INOP stickers over the ADF side of the display switch.


View Large View Medium
Click here for bigger photo!

Photo © William Jenkins
View Large View Medium
Click here for bigger photo!

Photo © Ben Wang




I got my head checked--by a jumbo jet
User currently offlineGordonsmall From UK - Scotland, joined Jun 2001, 2100 posts, RR: 22
Reply 12, posted (10 years 6 months 1 week 3 days 5 hours ago) and read 3589 times:

ADF sets on the 'buses is still a customer option.

Even boeing only have it as an option nowadays, I beleive the AA 737NG's have no ADF sets.

Regards,
Gordon.



Statistically, people who have had the most birthdays tend to live the longest.
User currently offlineAirplay From , joined Dec 1969, posts, RR:
Reply 13, posted (10 years 6 months 1 week 3 days 5 hours ago) and read 3583 times:

It really depends on the operational rules of the responsible civil airworthiness authority. Here in Canada you need to be able to conduct a non-precision approach at the destination after any single failure. For many destinations here that means having a funcational ADF or dual ADFs.

GPS is slowly becoming accepted as an alternate means but not all GPS installations are approved for "primary means" navigation. The vast majority of GPS systems on aircraft flying domestic service in Canada are "supplementary means" installations only. That means that in order to provide service to an airport with only an NDB approach, you need 2 ADF systems.

Some countries such as Kenya, rely almost exclusively on GPS navigation. This however is an economical issue rather than a systematic responsible risk assessment.


User currently offlineAAR90 From United States of America, joined Jan 2000, 3465 posts, RR: 47
Reply 14, posted (10 years 6 months 1 week 3 days 4 hours ago) and read 3580 times:

I beleive the AA 737NG's have no ADF sets.

Correct, which is why I can't find game scores no matter how many times a pax asks.  Crying



*NO CARRIER* -- A Naval Aviator's worst nightmare!
User currently offlineMandala499 From Indonesia, joined Aug 2001, 6761 posts, RR: 76
Reply 15, posted (10 years 6 months 3 days 3 hours ago) and read 3339 times:

DeltaGuy,
Well, how about slapping a GPS on the 732/722 and then steer direct to the waypoint using HDG mode. That's how they do it here on the waypoints, and use VOR when it's available. Yes, do it from waypoint to waypoint. The waypoint is installed the GPS database. So they just select and steer. Fun for a 4 hr trip? Well bring your enroute chart with you Big grin

Positive_rate...
How ? Bring a jepp chart, and the HSI with the CRS set. You would be able to calculate the ETA by looking at your GSpeed and your distance to go.

Mandala499



When losing situational awareness, pray Cumulus Granitus isn't nearby !
User currently offlineSlamClick From United States of America, joined Nov 2003, 10062 posts, RR: 68
Reply 16, posted (10 years 6 months 3 days ago) and read 3303 times:

Shaun3000

You can't exactly infer that the Apollo spacecraft were navigated to and from the Moon by INS. A more accurate statement is that they were propelled in a direction by use of timed rocket burns. After that, Isaac Newton took over and they mostly coasted along a trajectory that had been caculated for them.

I'm sure that intertial was part of, but not the only, means of determining when the craft was in the right position to fire the rockets.




Happiness is not seeing another trite Ste. Maarten photo all week long.
User currently offlineContact_tower From Norway, joined Sep 2001, 536 posts, RR: 1
Reply 17, posted (10 years 6 months 2 days 23 hours ago) and read 3286 times:

As long as SIDs based on NDBs are still around, and the SIDs are needed for obstacle avoidance, they are quite essential. Since the obstacle avoidance is often dependent on "climb to xxxxft, turn to intercept QDR...etc" it's not allways possible to replace NDB signals with INS waypoints. The presicion RNAV procedures goes a long way to remendy this problem.

Have experienced ABUS crews that have requestet a climbout on first part of a SID (VOR radial) until passing MSA, then fly dircect to next waypoint in SID. They where not allowed by company procedures to fly the next section, because it involves a tracking to intercept a QDR from a NDB station.
Was happy to help offcourse! Big grin


User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 18, posted (10 years 6 months 2 days 21 hours ago) and read 3244 times:

In the beginning...

aircraft were navigated over long overwater routes with astro navigation.
During WWII, LORAN (a) was developed, and generally provided accurate navigation fixes, within about one nautical mile, provided the operator knew how to read the screen properly, and lane skip was not a factor.
During this time, Doppler navigation sets were developed, and provided track and groundspeed readings to the crew, updated with either astro or LORAN.
In addition, during the early fifties, pressure pattern navigation was used extensively on Pacific and North Atlantic flights. This system of navigation used a high range radio altimeter to ascertain the proper (curved) path around high/low pressure areas, so as to provide the best tailwind/least headwind. Of course, not suitable for fixed tracks used today with jet aircraft.
Also, during the fifties/early sixties, Ocean Station vessels, operated by the USCG were on many Atlantic/Pacific routes. These ships steamed in a (broadcast) grid pattern and were equipped with a 2000 watt NDB, for positive position fixes.
The first INS units were generally quite accurate, offering navigation with a radial error not to exceed two nautical miles per hour of operation.


User currently offlineBuckfifty From Canada, joined Oct 2001, 1316 posts, RR: 20
Reply 19, posted (10 years 6 months 2 days 15 hours ago) and read 3184 times:

411A, you forgot to mention DECCA, though it was mainly used by the Brits (much more problematic than LORAN), and the entire network is decommisioned now. And I'm not sure if any commerical operations used the Doppler Janus system, but that was prone to errors dealing with flying over water, and was replaced in due course.

User currently offline411A From United States of America, joined Nov 2001, 1826 posts, RR: 8
Reply 20, posted (10 years 6 months 2 days 7 hours ago) and read 3206 times:

Yep, sure did forget DECCA.
Had one set fitted to an aircraft I was flying in the mid-sixties, and it worked quite well.
There was also Consolan, a development of the British Oboe system that was used in Europe to guide bombers to their targets.

Recall on a transpacific flight years ago in a B707, mentioned to the Navigator that if he could get me within five miles of BEBOP (then on the Woodside 236 radial, enroute SFO), would buy him dinner at Fishermans Wharf.
When Oakland established radar contact, he was actually one mile off...and the smile on his face was worth the price, for sure.
Astro navigation could be VERY accurate, if done properly.


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