RAF aircraft used Smiths Attitude/Heading Reference system?
 

Hi and sorry, if my question is off-topic or to technical: Anyone here knows whether
any RAF aircraft of the 1970ties and 80ties used an analog attitude heading reference system?

It is not from Tornado and probably not Harrier (used INAS and later digital systems) and
not Jaguar (NAVWASS and later FIN1064).

The reason for the question is, that I am interested in vintage UK made avionics and
I am maintaining some navigation equipment from this era. Recently I acquired a test
set from Smiths Industries (dated 1987 and last caled until 2001, RefNo 6C/6641376)
and I'd like to know which equipment this was used on:

https://cimg0.ibsrv.net/gimg/www.gmf...aaf80280a9.jpg

The test set obviously plugs between the LRU (or LURs) and the displays and can either
simulate the LRUs and/or genrate stimuli to the LRUs:

https://cimg0.ibsrv.net/gimg/www.gmf...888448e24b.jpg

Any hints are welcome and would help to preserve and/or reactivate this equipment. If interested
in my other activites, look at and Tornado-PEC-Page

Thanks, Erik.

Just in case someone recognizes the part numbers: Smiths Test-Set, Ref 6C/6641376 NSN 4920-99-664-1376, 4920996641376 TEST SET AND CABLES

Or the stickers applied to the unit:

https://cimg8.ibsrv.net/gimg/www.gmf...fcfacb38d3.jpghttps://cimg1.ibsrv.net/gimg/www.gmf...9c5b46623f.jpg
https://cimg4.ibsrv.net/gimg/www.gmf...aa464009f7.jpg

The Tornado's SHAR according to my research and some article in FlightGlobal
from the 1980ties was made by Litton and yes, this also uses/used mechanical
gyroscopes. This system is quite similar to the Litton LTN-51 inertial platform a
French seller wants to sell on eBay right now (search for "centrale inertielle" on
eBay). Nevertheless: Thanks for viewing and for the answer!

Thanks for the input so far - I asked at the Lightning preservation group whether they
recognize part number or the test set. But considering MFG date of the test set (1987)
and last calibration (2000) I think it is to late for the EE Lightning...

Very nice - and true :ok:

Just got a private email (many thanks!!) that the part number NDN looks like a Louis Newmark
product. Searching the internet one quickly locates an article in Flight Global pointing to the
venerable Siddeley Hawk as candidate using the Louis Newmark series 6000 AHRS system.
Cockpit photographs of the early Hawk show knobs for drift/latitude very similar to the ones on the
test set. So any Hawk / Louis Newmark experts out there?

Other options may be the Sea King or Wessex 3 helicopters according to the message I
got - but the Hawk matches the BFG date of the test set somewhat better...

Hi

i worked for Smiths in Cheltenham for many years. That is a piece of kit from Newmark , a firm Smiths bought in the 80s / 90s. Their factory was in New Addington. Most of their product was fitted to helicopters, so this may be a fruitful path to explore

edit I see you have the info - my post crossed with the one above!

Potentially Hawk MK1. My foggy memory from commodity avionics seems to think that.

Good luck

Thanks to Terry and to "Herc-u-lease" - I am pretty sure now, the test set is for the
Louis Newmark Series 6000 Attitude and Heading Reference System. Here is a picture
of the early Hawk's AHRS panel in comparison to the relevant section of the test set -
they look pretty similar:

Hawk:
https://cimg5.ibsrv.net/gimg/www.gmf...cf44b4abbe.gif

Test set:

https://cimg6.ibsrv.net/gimg/www.gmf...72a94de27d.gif

So I assume, the test set plugs between the black box and the aircraft on the
black box side (plugs are bigger than for example the HSI's) and I will try to get
hands on the AHRS hardware via eBay in the next months... I will post updates
here later - thanks to all for the help!

Hi Baigar,
As I remember it, the BAe Hawk T Mk 1 in RAF service had the "AHRS" as an upgrade to the flight instrumentation in about 1981. The fit was referred to as "A-hars" by the aircrew, and was a very good upgrade of the original Hawk attitude system which toppled in aerobatics. Generally, the aircraft with the A-hars upgrade were much preferred by the pilots. Cheers

OAP

My only experience of the Hawk was in pre-AHRS days in 1980-81 at Valley and Heaven-in-Devon. The compass system was dreadful and fundamentally unfit for purpose and the attitude indicator wasn't much better. I recall reading some flight safety comic which stated "The deficiencies of the Hawk compass system were known before the aircraft entered service" :\ I can't see that being acceptable today.

But why was the 'student's friend' never fitted? By which I mean the superb offset TACAN system fitted to the Gnat. It would only have needed a couple of potentiometers and a switch...

When was the dorsal fin trailing edge extension fitted? The jets I flew were never so fitted; according to the exponents of triggernometry (the QWIs) that's why the sight was such a bugger to keep steady during strafe sessions.

Still, a nice little jet though, without the quirks of the Hunter fuel gauging system or the short legs and complex longitudinal control system of the Gnat.

Hi there - many thanks for the reminiscences. So we obviously have real users here ;)
OK, the AHRS had a forerunner before 1980/1 did this also control the attitude indicator
AND the HSI as the AHRS 6000 did later on or was it compass-only? Was the panel
changed in 1980/1 during the update so that the earlier panel was different from the one
shown above?

Checking eBay for Newmark parts I found some stuff from a Buccaneer system which
also looks little similar, but this (I guess older system&) seems only to be a gyro
compass system (no erect button and GYRO COMPASS written on panel)...

As the test set was used until 2000 I guess it was the later A-HARS / HARS 6000.
Some far fetched question: Does any one have got part numbers of the gyro and
amplifier boxes or some form of air-publication on this system?

Ahh, just found some more parst from the Buccaneer compass-only system on eBay
at the same seller: Directional Gyro and an Amplifier which was probably part of a
bigger box.... But I believe those are NOT from the AHRS 6000 above...

To increase the chance to get in touch with an expert on these systems
I started a new thread in the keypublishing's forums asking specifically
for the Hawk's AHRS.

BEagle,
Not too sure what you refer to. You could rush around in a great jet and when the Bingo light came on it was time to go home.

Climb to height, fix position and if tight on gas - stop cock and Precautionary 1 in 1.

Worked every time.

Thanks for this comment - it lead me to do some reading into the Hunter's systems
and it was quite interesting to learn how it worked and what the "Bingo light" is ;-)

Those who can properly remember that far back will recall that "the Bingo light" was two lights - one for each forward tank, set at 650 lb per side.

Indeed - and the call of 'Piccadilly' to inform the rest of the formation when they came on...

Quirks? Vapour vent release failure, transfer failure, gauges which were useless except in straight and level unaccelerated flight.

Great jet though!

The top photo in Post#10 is how I remember the panel in the VC10.