BBMF Merlins cleared to fly again

Hi all. Well, a lot of the ‘transponder talk’ went over my head but, during a visit to the Flight today the (excellent) guide informed us that the Merlin engined aircraft had briefly been grounded after the supercharger in one of the Spitfires had ‘exploded’ in flight……

An unusual visitor was also there during our visit, as shown in the attached photo.

hypersonic. No problem, thanks for clarifying. 

As far as I’m aware the only product that conforms to ACAS requirements and is accepted Worldwide is still TCAS II with version 7.1 software. 

Oracal – My ref to not using it in the USA was commenting on SkyEcho as a product. The FAA have not certified it. I can’t find any evidence of its certification in Europe either. However, other systems are available in the USA and all most certainly in Europe to cover the “gap”.

I have corrected my previous thread entry # 17 Jul 12:58.

Sorry!!

TCAS, also known as ACAS is mandatory for commercial aircraft and helicopters. For flight desk indication it can be as simple as replacing the VSI (s) with an electronic version (plus required black boxes and aerials to feed the info in/out, oh, and the small matter of certification). That’s what happened many years ago when the requirement became mandatory for commercial aircraft not fitted with EFIS screens. 

These days TCAS RA or TRAFFIC warning are all part of driving planes for a living.

I don’t follow your comment not to use TCAS in the USA, or are you referring to PFLARM? 

So it was an unplanned ……..

Whilst this equipment, SkyEcho, has been around for a few years now, I have not seen it before. A great aid to situational awareness. Developed for the GA market.

My background of fast-jets and the Chinook use a system under the generic title of TCAS (Traffic Collision Avoidance System). However, the limited space available in BBMF aircraft I suppose needs another – just as capable solution.

But don’t try using, SkyEcho, it in the USA!!! 

The Lancaster’s SkyEcho was accidentally loaded with the HEX code for Chipmunk WK518, hence both appearing to be in formation. The situation has been rectified. The Lancaster was “squawking” as normal on its Mode S transponder with the relevant ATC around the UK. SkyEcho is used to supplement PFLARM for situational awareness. PFLARM  – Power Flight Alarm Core, collision warning system.  

Jaguar34 – I’m not familiar with the SkyEcho system. Presumably the box is picked up by the Captain / Pilot when signing for the aircraft. Some how the Captain got hold of the wrong box or didn’t update it – if that is the correct procedure. Which causes more concern such an incident should never have happened. By default the Lanc was seen “by the world” as being Chipmunk WK518 with no top level clearance from the MAA.

Also of course how did the Lancaster get to the South West with nobody in the world of ATC noticing.

An unplanned deviation from a criteria based standard of competence me thinks!!

Oracal – earlier in this thread you were asking about SRIM activity at Leconfield. I will create a new thread tomorrow to answer your points.

Cheers….

Jaguar34 – that makes sense. It does seem a tad naughty procedure to use another aircraft’s ADS-B.

Thanks.

All BBMF aircraft have Mode S transponders which are not transferred between aircraft. The Lancaster had been flying with Chipmunk WK’s SkyEcho however, which has caused some confusion! The pilots fit the SkyEcho’s (a portable ADS-B) when they get onboard an aircraft.

No apologies needed , a fascinating read  ,Thank you 🙂 

hypersonic. Thank you for the info – most interesting, and you are correct about the Nimrod transponder issue being pre 2006. 

I don’t know if you ever encountered the SRIM Squadron during your career in the RAF? I was an involved in the team between 1972-75, thereafter it moved from Leconfield to Wyton. The time and cost to do the trial fit of new ‘electronic gizmos’ was enormous! Typical military. I wonder if it still exists? 

I see FlightRadar24 uses ADS-B for its info, so I guess Mode S Enhanced required? The Lanc / Chipmunk case does seem odd.

Cheers! (and apologies to the OP for the drift)

With apologies to trumper, the thread has changed somewhat. Oracal, in some respects the answer, to your question, is actually within the question. Mode-C is a basic system and therefore changing the box between aircraft over a decade ago wouldn’t have been a problem. There are no unique codes built into Mode-C. The activity you speak of almost certainly pre-dates the Military Aviation Authority which was formed on the back of the loss of Nimrod MR2 XV230 in Sep 2006. At that time Mode-C was the standard. Mode-S boxes are very much an individual aircraft allocation. They have an embedded 24 Bit Address code in the contained software. ATC and flight tracking sites see that code as 40xxxx for UK registered civil aircraft and 43xxxx for UK registered military aircraft.

Looking back on FR24 and using a bit of grey matter I drew the conclusion that the Lancaster normally 43C392 was pretending to be Chipmunk WK518 AKA 43C38E. Others in this thread had observed unusual activity around that point.

Having been in the military side of UK aviation for over 3 decades I don’t know of any such aircraft still flying, on the military register, with Mode-C. If the Chipmunk was on Mode-C switching its box to the Lancaster (PA474) would not have required, the Lanc to use the call-sign of WK518. As Mode-C boxes, if that was what was in use, are not uniquely coded ATC would have seen an airborne aircraft – but not its “true” ID / type.

The chipmunk, of course, is not normally used for display activity being used by the BBMF in a support role only.

Hope that clears up your question.

hypersonic – if the BBMF Chipmunk has a mode S transponder it would be worth more in £££ than the airframe. I remember the Nimrods at Kinloss has so few of them that they were rumoured to be swapped from aircraft to aircraft. Do you know if it is a mode C or S in the Chippy. Just interested…

Wearing my avionics hat – the Mode-S code 40xxxx or 43xxxx is inbuilt into the transponder box. It responds when “pinged” by ATC radar with the unique code to ID the aircraft. Also providing speed / heading / altitude / call-sign etc.

I spotted “WK518” flying over Exeter, the other day, on FR24. However, I did become a little confused at the speed the “Chipmunk” appeared to be doing!!

I think what happened is the Lancaster was using the Chipmunk transponder box – I hope with permission from the Military Airworthiness Authority. Otherwise very naughty. PA474 was using the WK518 call-sign at that time.

Anyhow, good to see all the Merlin powerd aircraft previously grounded back active again.

DH Chipmunk normal cruise is 90kts, – slower than a Lancaster.

Other than a few exceptions the ‘squawk’ code is allocated by ATC for each flight by the aircraft. The other details you would see on a mobile app (call sign, aircraft type etc) are stored by the ATC system and are bought-in (£££) by the app developers/owner for you to see.

The use of more than one transponder by aircraft in a formation is discouraged. Back in the 1980s the ATC computer system had software to detect ‘merging’ (getting close to each other) and would set off alarms to the radar controller. We discovered this when doing a photo shoot in a Shorts 360 and formatting with a Cessna. Today the modern mode S transponders communicate with each other and with ATC to alert and provide warning/vertical manoeuvring instructions in a system known as TCAS or ACAS. Trying to formate two or more aircraft fitted with and using with TCAS/ACAS would be a nightmare! 

I’m hoping to visit the Flight’s visitor centre soon. If I remember, I’ll try to find out…….

I did wonder if the Lancaster actually did have the Chipmunk in tow for a while; something to do with the engines (but I couldn’t imagine what) or maybe air-to-air photography?

I wasn’t sure if a Chipmunk could keep-up with a Lancaster?

I can only guess it was an ‘air-test’ of the transponder hardware?

I’m not really sure of the mechanics of transponders; where is the ‘identity’ assigned between the aircraft hardware and my mobile-phone?

Tanks? I understood what you meant (but I’m equally happy to talk about tanks all day)!

normally only one aircraft squawks if the are flying as a flight, BBMF you will sometimes see just the Lanc and not the fighters

Tanks? Oh I love predictive text on phones and having aging eyes! I did, of course, mean ‘Thanks!’……