Bae 146 decompression ???

[First.officer]

Heard a rumour (strange that eh ?!) about a 146 from a South East operator having a decompression somewhere over the East of England ?? anyone know anything about it ?? just curious.......lol

F/o

[Basil]

Do they fly high enough for it to matter? :}

[First.officer]

Well, granted they may not fly at an altitude/FL that may cause huge concern, was just keen to know the story (if there is one...!!), just heard one or two rumours about this and was interested ! will wait and see i guess........

:ok:

[Graybeard]

I was told they were limited to FL290 because the skin was too thin to take more pressurization.

Pacific Southwest Airlines had a decompression in the 1980s at 270 when #4 engine came apart and sent hot shrapnel into the cabin. It missed everybody, but pieces were sizzling on the carpet as SLF kicked them around to prevent a fire.

rdr

[IrishJetdriver]

The 146 is certified to FL310 or FL300 depending on model. They're limited to FL280 simply because they are not RVSM capable. I think that the ASI is not corrected for compressibility and thus you have to level off approx 100ft below your planned FL and the aircraft will apparently "climb" the last bit as the speed increases.

I did a test flight once at FL310 in the 146 unpressurised. There was an almost overwhelming desire to take the mask off just to see what would happen.

[Basil]

There was an almost overwhelming desire to take the mask off just to see what would happen.
Good idea to have someone standing by to replace O2 mask :ok:
You just lose consciousness - there one second, gone the next.
No feeling of dizziness or other warning - I argued with the doc that I hadn't passed out - I had.

[390cruise]

Last evening I overheard guys talking about this event in my local pub!

The the gist of the story related to an airtest, problems with a hatch lock and the crew oxygen.

I just hope the flight was not being flown by a management pilot!!

390
Waiting for the final report!

[First.officer]

Thanks for the info. guys - most useful !

Interesting about the pub conversation 390cruise - guess that confirms my source is at least correct in that it happened ! lol - and totally agree, would be awfully embarassing i guess if a management pilot !

:ok:

[SkyKite69]

Rapid Decompression at 20,000ft, time of useful consciousness = 3mins. :eek:
Perhaps the CAA will deliver out 1000 lines to the individual concerned:

"I will do my checks before I start the aircraft"
"I will do my checks before I start the aircraft"
"I will.......

The fact I have to fly up in the air in the same airspace as this imbecile is simply abhorrent. It's a disgrace! :ugh:

[Smilin_Ed]

There was an almost overwhelming desire to take the mask off just to see what would happen.

Have you never gone "up" in a low pressure training chamber? :confused:

[remoak]

I was told they were limited to FL290 because the skin was too thin to take more pressurization.

and

The 146 is certified to FL310 or FL300 depending on model. They're limited to FL280 simply because they are not RVSM capable.

Utter crap!

The max operating altitude depends on the pressurisation system fitted.

If you have a BAe Dynamics analogue system, it's FL300 or FL310.

If you have an NGL analogue system, it's also FL300 or FL310.

However, if you have an NGL digital system fitted, the max operating altitude is FL350.

FCOM 2.2.13 for anyone who doesn't believe me...

And the airframe is plenty strong enough to go higher than that, being British... ;)

Also, the only thing you need to do to a 146 to get RVSM approval is fit proper digital altimeters. That fixes all the altimeter inaccuracies that have always plagued the 146.

[spannersatKL]

Agreed the 146 is one of the original Brick outhouses.....but take a look at one when pressurised on the ground!! (Maintenance Procedure). The fwd fuselage where there are few if any stringers and only the frames and skin the skin can be seen to bulge out between the frames!! A good machine to keep flying...:}

[Dash-7 lover]

I tend to believe Irish Jet Driver re RVSM. The elderly 146's we had in Citiexpress were limited to FL260 even on MAN-FRA and INV-LGW, probably because it was dangerous to fly them any higher lol. Mind you the most basic of machines G-MABR proved her worth many times over.

I thought the hairdryers would prove useless above FL260, then what do you expect from engines that worked better on helicopters...

And that brings me to the E145 that although limited to FL370 hit FL390 to clear the top of a CB and was briefly grounded on arrival for checks. No doubt there's redundancy built in all of these.

[JW411]

I can confirm that it was a relatively easy exercise to upgrade the BAe146's altimetry so that it would conform to RVSM requirements.

However, the mods were horrendously expensive and simply not worth the effort.

The reduction in fuel burn between F310 with RVSM and F280 without RVSM was pretty well negligble.

Don't forget that the average stage length was probably less than 1.5 hours so you weren't up there for very long.

From my point of view, the best part of flying the 146 was the fact that it ran out of fuel after 3.5 hours! (Sitting on your ar*e for 14 hours is not the best of fun once the novelty has worn off).

[AEUENG]

Once did ZAG-MAD and that was around the 4 hr mark. 146-300 could hit FL310 whereas the -100/-200 were FL290 limited from memory. Could not enter RVSM airspace due to the altimetry system originating from a sopwith camel! Aircraft without the TGT roll back (eng a/ice valve mod) being incorporated were limited to FL260 in icing conditions.

Still a pretty decent aircraft but it did keep us engineers busy, great for contracting though....lots of overtime!

[Captain-Crunch]

God I loved the low alt 146. With ALF 502/503's, we were blowing engines left and right on the 100, so the company took us out and three-engined takeoff qualled all of us in the actual airplane! They figured we were all going to be at an out station and would need to ferry it back to a mtc base sooner or later! Interesting procedure. We wouldn't spool up the asymmetrical engine until 80 kts.

That was my first clue to update my resume....

Solution was to throttle back to .75 cruise according to Avco Lycoming. Of course, on a busy corridor in the cheap fuel days that made us very unpopular. We started having to file for FL260 and often got much lower because ATC got tired of vectoring us off the airway to let everybody by.

But with those big beautiful picture windows on a new airplane at low altitude over the mountains it was a shear delight, even if it wasn't particularly profitable. Next job was old 74 freighters where most of the windows were so crazed I couldn't see out at all!

Ah the 146. Small gas tanks, pretty girls, home all the time... :ok:
Not sure now why I wanted to commute just to fly the big iron.... :confused:

[ozineurope]

In early 1990s a BAe146 suffered a total (yep all 4) engine failure/s due icing. The aircraft was operating at FL310 between Karratha and Perth when the crew called mayday.

Engine restart was achieved when the aircraft was around 10,000ft. VH-JJP was the reg operating as Airlines of WA flight. Since then all Australian 146s have been limited to below FL290.

I am pretty sure the limitation is still in effect. ATSB report should be available on the ATSB site.

[Capt Pit Bull]

Solution was to throttle back to .75 cruise

<cough> Mmo 0.72 iirc (for the RJ ayway, I doubt the 146 was higher)

[DutchBird-757]

On th RJ100 and RJ85, with a digital press sytem max alt is FL350. With the analogue system it's FL330. VMO .72, typical .70 crz speed.

[ozineurope]

Bral - ta.

I was on APP in Perth the night it happened. Very quiet room when he made the call and for the next 20 minutes or so. Was most pleased when he got them going again, not as pleased as the people on board though!!

[remoak]

I am pretty sure the limitation is still in effect

No, it hasn't been for a long time now. It was only in effect until engines were fitted with a de-ice mod in the engine splitter. That mod was mandatory every time an engine was stripped, and there was a time limit. The last one would have been done quite a few years ago now.

From memory, there were quite a few issues surrounding that event, and the crew were at least partly to blame for what happened. There is a pretty good instructional video about it, that was made by the airline after the event.

[safetypee]

Engine rollback – ‘the crew(s) were partly to blame’.
With hindsight this view is bit harsh. The icing phenomenon was previously unknown and only after the statistics from events was it associated with very large Cbs. More recently Boeing and Airbus have encountered problems.

There were some human aspects, particularly after the initial warnings not to fly anywhere near Cbs, but also there were more general circumstances. Many of the incident aircraft were relatively light, thus cruised at a (relatively) higher altitude; crews believed that no return on radar was the same as no threat due to mismanagement/misunderstanding of WXR – corner cutting near Cbs, and some of the engine air-bleed tolerances were at minimum - maintenance.
In at least one event a crew ‘induced’ depressurisation (four engines shut down – not in Oz), presented an interesting dilemma between descending relatively fast (for lack of O2/pressure), pausing at FL200 to obtain a relight, or to reduce altitude loss to maximise the much need overwater glide range. Again, with hindsight, a compromise at FL200 provided a balance between risks and needs; at least the engines relit.

In many aircraft, crews over reacting to a depressurisation warning; pilots are taught the depressurisation drill in association with an emergency descent, thus they become automatically sequential. Whereas in reality after donning the O2 masks, there is time to check the actual cabin pressure and cabin rate, and possibly some fault diagnosis.
The more experienced 146 Captains would look at the overhead panel and check the outflow valves, which under manual control had a sluggish response and lacked feed back of the selection except for air pressure on the ears. Many pilots did not have opportunity to gain this knowledge from annual airtests (now discontinued), and the simulator was ineffective.
Depressurisation; a quick response required for O2 masks, no rush to descend … check … then act accordingly.

[JW411]

The other quadruple hush (caused by rollback) happened to a Flip I Lino crew (JP was the captain). They got the first engine running again about 3500 ft above the sea north of Brunei and finally made it to Singapore with three engines running.

Like the Oz crew, they were flying close to large Cb activity at high altitude.

The interesting thing (to me) was that both crews were cruising with the TMS in TGT/SYNC mode.

Now, we abandoned this mode of the TMS as worse than useless right at the beginning in 1987 for it was a contradiction in terms. (In effect, it only regulated TGT on the master engine and allowed the other three to float whilst regulating SYNC).

The Flip I Lino crews were initially trained by us in UK and were warned about using TGT/SYNC. However, whilst they were waiting for their aircraft to be delivered, they were given further training in OZ.

I have often wondered, if having one engine roll back in icing conditions and having TGT/SYNC selected, dragged the other three back with it?

In any event, all the engines have since have been modified and I am now retired so I suppose I don't give a stuff one way or the other!

[john_tullamarine]

the crew were at least partly to blame for what happened

I think that you need to provide some evidence for your contention.

As far as I am aware, Phil was considered to have done a pretty good job at the time.