Today's mystery acronym: 'T6NL'

[Dr. Red]

Quick question.

Can some wise individual tell me what the acronym T6NL means?

Context: CVR transcript. "T6NL" is announced by GPWS computer in aircraft suffering engine trouble.

Can't find anything on Google; seems a bit cryptic.

Thanks in advance...

[NigelOnDraft]

T6NL was (is) a major "Oh ****" caution in the Hawk (Adour) - I think.

"T6" meant excess Temp somewhere (presume point 6 in the engine). "NL" meant LP Fan overspeed - I think. "T6NL" meant one or the other - invariably the former, and therefore a surge / mech fail / not your day.

Tends to occur frequently in the Sim and Accident Reports. Fortunately for me, not in the aircraft... :)

OK for 16 years since I flew it ???

[BobZyurUnkl]

Have a look at this, If you say the hawk does this, could this be the guys at NFTC in Moose jaw.





http://www.fazed.org/video/view/?id=47#boidie



PS-Nice British Accent

[Blacksheep]

By the GPWS = Ground Proximity Warning Computer ()?
I think not.
More likely from a Central Warning System Computer.

In general, 'T' represents temperature, 'N' shaft rotation speed and 'L' Low Pressure. The number 6 would be Stage 6 so we have a warning concerning Stage 6 Temperature and the LP shaft speed. Possibly a compressor surge. I say 'in general' but unfortunately the actual acronyms used in different aircraft electronic systems are getting very type oriented these days.

[Dr. Red]

Sorry, it was imprecise of me to call it the "GPWS computer", but the warning was reminiscent of GPWS.

I must say it seems to be poor human factors design for the system to announce some pseudo-cryptic code, "T6NL," instead of something more intelligible -- e.g. "Warning, Engine Overheat" (for instance). But perhaps I'm being too picky.

The video of that CT-155 incident is impressive. With a student and instructor onboard, it suffered a bird strike at 200 feet after a touch-and-go. Engine appears to fail, instructor takes control, and a few moments later they abandon the aircraft. The crew were extremely professional throughout the incident.

Both ejected safely but sadly the instructor damaged his spine.

The whole incident is over in about 30 seconds - it just shows how quickly things can turn to custard!!

[NigelOnDraft]

Dr Red...

I must say it seems to be poor human factors design for the system to announce some pseudo-cryptic code, "T6NL," instead of something more intelligible -- e.g. "Warning, Engine Overheat" (for instance). But perhaps I'm being too picky. I think you are being a bit too picky... The T6NL is a "caption" extermely well known to any Hawk pilot (must be if I can remeber it all after all thes years!), and all "bitching betty" does is restate the (prioritised) illuminated captions. Since the pilots would "know" well what T6NL means, seems fine. "Engine Overheat" is misleading, since there are other "overheat" type cautions often present, and why confuse with the "panel" saying one thing, and bitching betty another? In addition, any Hawk pilot will have heard and practised the consequences of T6NL every Sim trip... I certainly did (albeit pre the voice call out).

Incredible video of an extrmely well handled emergency... Just watch the flying pulling up to, and then maintaining exactly 125K - 130K, whilst trying to restart, turning back, briefing other pilot, R/T call and ejection. The "pitch down" at ejection is interesting to those of us (still) flying "light jets" when considering the effect of 1 ejection on the remaiing pilot / seat v parameters... an education :)

[Dr. Red]

Thanks everyone for your helpful replies.

[normally right blank]

Many years ago (1976?) after Belenko defected in a MiG-25, there was a feature in Readers Digest about the incident. When he ran low on fuel a female voice "reminded" him. He was very surprised at that. Which surprised me a lot. (That he was not aware of the system.) (Or did it only surprise the "ghostwriter"?)
Was the B-58 the first American type with the system? (female?)
Digressing again. The (deep) stall warning of the Trident was so infernal, that it was mentioned in the "Staines" accident report as a possible contributory factor.

[McDuff]

I think you are being a bit too picky... The T6NL is a "caption" extermely well known to any Hawk pilot (must be if I can remeber it all after all thes years!), and all "bitching betty" does is restate the (prioritised) illuminated captions. Since the pilots would "know" well what T6NL means, seems fine. "Engine Overheat" is misleading, since there are other "overheat" type cautions often present, and why confuse with the "panel" saying one thing, and bitching betty another? In addition, any Hawk pilot will have heard and practised the consequences of T6NL every Sim trip... I certainly did (albeit pre the voice call out).

I was on the first Hawk course (11 Cse) at Valley in 1977. The T6NL warning was supposed to indicate that the temp- or NL-limiting system had failed so that you could take corrective action. It was simpler than the myriad warnings that might have been produced if the engineers had had their way ;-)

I, too, am impressed by the calm way the IP handled this emergency. I shall show it to my students on a ground training day.