MAYDAY issued over Irish Sea
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Growler:
Sorry, old boy, but it seems that they did'nt have the problem sorted, as they were referring to themselves as "Mayday BRT 903" all the way to MAN, and squawking A7700. They repeated that they were still having control difficulties on a number of occasions after they decided to divert to MAN.
Now, if they had the problem sorted, they would have cancelled the MAYDAY, "Full Stop", to quote your goodself, wouldn't they?
Sorry, old boy, but it seems that they did'nt have the problem sorted, as they were referring to themselves as "Mayday BRT 903" all the way to MAN, and squawking A7700. They repeated that they were still having control difficulties on a number of occasions after they decided to divert to MAN.
Now, if they had the problem sorted, they would have cancelled the MAYDAY, "Full Stop", to quote your goodself, wouldn't they?
Guest
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we had the same problem a couple of months ago on the 145 soon after take off at CDG.pitch trims, main and back up, were not operative.there is no way to trim the 145 manually -no wheel trim-
.airspeed was kept low and we turn back to CDG and land safely.
the concern is that landing would not have been so easy if the trim had failed at higher speed
.airspeed was kept low and we turn back to CDG and land safely.
the concern is that landing would not have been so easy if the trim had failed at higher speed
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Prune Radar
Sorry, must misread the Bally posting....thought it was a 146.
I believe however from my instructing days that it would pitch up anyway. Y'know, effects of power and all that. Don't think you can certificate them otherwise as it would be unstable. Power off, nose pitches up, speed bleeds off, aircraft stalls. Should have stayed in bed this morning. Any aerodynamicists out there?
Sorry, must misread the Bally posting....thought it was a 146.
I believe however from my instructing days that it would pitch up anyway. Y'know, effects of power and all that. Don't think you can certificate them otherwise as it would be unstable. Power off, nose pitches up, speed bleeds off, aircraft stalls. Should have stayed in bed this morning. Any aerodynamicists out there?
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Thanks Bally, that explains it 
Anyone able to offer advice on thrust and pitch change effects on something like the 145 ?
Just out of professional interest.
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PPRuNe Radar
ATC Forum Moderator
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Anyone able to offer advice on thrust and pitch change effects on something like the 145 ?
Just out of professional interest.
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PPRuNe Radar
ATC Forum Moderator
[email protected]
Guest
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Re_ERJ145 TRIM
/This is a known problem,and is caused if the trim is not correctly set during climb out due rough wx. The load against trim jack is to much to over come. Solution is to reduce airspeed to <200ias and re trim when the load is reduced,you can achieve the same result by triming in the opposite direction this will unstall the trim jack.
/This is a known problem,and is caused if the trim is not correctly set during climb out due rough wx. The load against trim jack is to much to over come. Solution is to reduce airspeed to <200ias and re trim when the load is reduced,you can achieve the same result by triming in the opposite direction this will unstall the trim jack.
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Sorry Bally,
Its entirely possible for an increase in thrust to cause a pitch down, it just depends where the line of action of the force is relative to the C of G.
If its above, increasing thrust causes a pitch down. If it below, causes pitch up.
Its just basic mechanics.
What happens next, for most aircraft most of the time, is that speed increases causing you to either start to climb or to have to trim nose down to avoid a climb. There may or may not be other factors mixed in (e.g. changes in prop effects, changes in downwash on the tail etc).
Don't confuse the effect of changing power with changing airspeed, nowithstanding that changing the former will also tend to change the latter.
CPB
Its entirely possible for an increase in thrust to cause a pitch down, it just depends where the line of action of the force is relative to the C of G.
If its above, increasing thrust causes a pitch down. If it below, causes pitch up.
Its just basic mechanics.
What happens next, for most aircraft most of the time, is that speed increases causing you to either start to climb or to have to trim nose down to avoid a climb. There may or may not be other factors mixed in (e.g. changes in prop effects, changes in downwash on the tail etc).
Don't confuse the effect of changing power with changing airspeed, nowithstanding that changing the former will also tend to change the latter.
CPB
Guest
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Is there not a story of a DC10 that lost pitch control through the control column....crew used power from wing engines to pitch up - and power from (high mounted) tail engine to pitch down?
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Hunting is bad!!
Support the right to arm Bears!!
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Hunting is bad!!
Support the right to arm Bears!!
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Bear Cub, you are referring to the accident at, if I remember correctly, Sioux City. It was indeed a DC-10 where the crew had lost all pitch control after an uncontained failure of the No 2 engine.
The crew did a fantastic job and managed to get the aircraft down using the pitch effect of the underslung Nos 1 and 3 engines. There were unfortunately casualties.
The industry learned a whole raft of lessons about both CRM and system redundancy after that one.
The crew did a fantastic job and managed to get the aircraft down using the pitch effect of the underslung Nos 1 and 3 engines. There were unfortunately casualties.
The industry learned a whole raft of lessons about both CRM and system redundancy after that one.
Guest
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Thanks Capt Pit Bull and BIK_116.8. The wise old aerodynamics professor’s aeroplane sounds like the unachievable perfection of the designers art. Or is it?
Just out of interest and before the thread gets consigned to the Tech Log forum. Does anyone know of a large aircraft which pitches up when thrust is decreased? Saw a bizzare (German?) aircraft recently with the pods mounted on top of the wing. Surely that must.
Finally, and most importantly. How does one get those little dancing smiley faces to appear in a post?
Just out of interest and before the thread gets consigned to the Tech Log forum. Does anyone know of a large aircraft which pitches up when thrust is decreased? Saw a bizzare (German?) aircraft recently with the pods mounted on top of the wing. Surely that must.
Finally, and most importantly. How does one get those little dancing smiley faces to appear in a post?
Guest
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Float Planes are predominantly trimmed in this manner.
With there being a relatively low positioned drag vector due to the parasite drag on the floats and the engine being mounted considerably above, there is a large nose down couple whilst under power, this requiring a large amount of nose up trim to balance the couple. Should the thrust drag couple now be reduced i.e. reducing power, the nose up trim will now have more effect on the aerodynamic forces.
The way around this is to fly inverted but I still haven't mastered the landing this way.
In order to have the Smiley faces enabled, make sure Smilies is not disabled at the bottom of the posting text and read the smilies legend for the character sequence which will activate the animation (under smilies legend).
Stick
With there being a relatively low positioned drag vector due to the parasite drag on the floats and the engine being mounted considerably above, there is a large nose down couple whilst under power, this requiring a large amount of nose up trim to balance the couple. Should the thrust drag couple now be reduced i.e. reducing power, the nose up trim will now have more effect on the aerodynamic forces.
The way around this is to fly inverted but I still haven't mastered the landing this way.
In order to have the Smiley faces enabled, make sure Smilies is not disabled at the bottom of the posting text and read the smilies legend for the character sequence which will activate the animation (under smilies legend).
Stick
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I am not a design or certification engineer BUT I understand that FAR23 and FAR25 (certification standards for civil aircraft) require that the thrust/drag couple is arranged such that a reduction in thrust will cause a nose pitch down moment, and an increase in thrust will cause a nose pitch up moment. This is achieved by having the average thrust line BELOW the average drag line.
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Must add an amusing side to this subject.
My collegues were involved with one of the E145 "pitch/trim" incidents. Apparently the pilot asked for a long, dry runway that was into wind (this was the weekend of the storms/high winds/rain). Somebody in the tower suggested "Tenerife"! What's more - the suggestion was Genuine!
My collegues were involved with one of the E145 "pitch/trim" incidents. Apparently the pilot asked for a long, dry runway that was into wind (this was the weekend of the storms/high winds/rain). Somebody in the tower suggested "Tenerife"! What's more - the suggestion was Genuine!
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Smoketoomuch. Yes Im aware that it is illegal to listen to certain radio-frequencies without a licence. I read the report on one of the many news wire services that we use in our profession. Thats how we are alerted to certain incidents. So Im afraid your censure was wasted on me.
