Here is the Marquise SE climb chart.


There is no corresponding chart for the legacy jets that I can find. Instead, they have segmented takeoff engine failure charts but it isn't clear how you translate the charts into climb rates.

The turboprops lack such charts, so they only give you OEI climb rates when everything is all cleaned up and good, not how you get from engine failure on or near the runway to that point.

The key point is that for a jet to achieve the numbers requires very simple pilot actions, basically just fly the airplane on speed. For a turboprop, that is not so, pilots have to correctly manage the airplane configuration and also fly on speed.

If you look through the accident record, you will find dozens of mishandled engine outs in turboprops, and close to none in jets (in fact, I don't know of any myself). So the jet safety is not just the performance you get single engine, but the ease with which you achieve it.

Mike C.

Because that is appropriate to the thread subject for the number of people desired to be transported.


Yes, because you don't understand jet charts and how they measure takeoff performance, and because you don't have charts or graphs to cover the engine failure at liftoff scenario in your turboprop but I do for the jet.

You are comparing a jet lifting off the runway, one engine inoperative, with gear down, slow at V2 (not far from Vr), to a Commander cleaned up, gear up, on speed already in the air. Can you even tell me what your climb rate is gear down at Vr? Hint: it won't be anywhere near 650 FPM at 6000 ft, 30C, and it could well be negative, too.

Given the jet pilot has to make no config changes in 1st segment, it would be appropriate to ask what your climb rate is with both gear down AND prop in NTS and not feathered? Now that is almost certainly negative climb gradient.

The Mustang maximum takeoff weight for a Mustang at 30C, 6000 ft is 8240 lbs per figure 4-21 in the AFM, thus less than gross weight. This is precisely to give it positive rate on engine failure.

You also picked a wheezy jet with a low thrust to weight ratio and compared it to the best Commander with -10 engines. So your foot is on the scale a bit by picking the contenders. A Mustang isn't fitting the thread mission profile.

A Citation II (in budget for the thread subject) at 6000 ft, 30C, MGTOW (13,300 lbs) has a 1st segment (gear down, flaps up, V2) gradient of 1%, second segment (gear up, flaps up, V2) of 2.7%. With the jet, if you operate within the limitations, you can handle an engine failure at ANY POINT with assured positive gradient. You don't have that for your turboprop.

I seriously cannot recall a jet accident where the jet could not climb out on engine failure.

I also can't recall ANY airport in the thread subject service area that is at 6000 MSL.

Mike C.

I do have a chart for my Commander with gear down and there is very little affect on performance.

Gradient of 4.8
500 FPM Rate of climb
292 ft per nm

See chart below.



Again see the chart below! Commander climbs great with gear down and at only 4kts above VR!

Yes the comparison is with the gear down. What other possible configuration would he be at and have an engine failure on take off??

Mike in a jet it goes like this V1, hand off throttles, VR nose wheel starts coming up then you liftoff, quickly thereafter you are at V2. You are expected to maintain V2 through the first and second segment climbs.



The gear in the jet will be selected up or at least be in transit during the 1st segment. That is a significant configuration change that happens during the first segment.

I don’t have a chart for that configuration, gear down and prop NTSing? Do you? How much drag is there with a prop in NTS. There is not much drag that is my experience what about you.

There would have to be two major checklist items missed by the pilot, forgetting to retract the gear and not feathering the prop. Even still I believe the commander would outclimb the jet. Guess I will have to demonstrate that next time during training.

See my comment about getting trained up.


No kidding that’s the point!! A TP can do it at MGW and the jet cannot.

Those are limitations you get with a little jet. Got to leave early from your ski trip.



Are these supposed to be impressive numbers. Comparing a jet that is at less than gross weight to a TP at MGW and the TP still wins??

I don’t see it. Using a simple gouge to convert gradient to FPM (gradient x GS = Rate in fpm)
I am guessing the citation VREF is 110.

1st segment 110 fpm.
2nd segment 297 fpm.

Those number look pretty bad compared to the numbers for an old TP.

You picked the littlest one to make the point, not apples to apples.


13,300 lbs is Citation II MGTOW.

In the end, turboprops crash from engine failures and jets rarely if ever do. They are just safer.

Mike C.

You compared it to a Citation ll and it did not look too good against that. It’s not just the littlest ones it’s many of the older SP jets.



No in the end it’s about training.



My mistake I was looking at ones with GW increase mod.

American airlines flight 191

United airlines flight 232

Ethiopian airlines flight 604

Those are probably enough fatalities just there to eclipse (no pun intended) all the fatals combined in TP's from engine failure.

Severed hydraulic lines, caused slat retraction and stall. Absent the hydraulic issue, the plane would have flown.


Loss of flight controls due to severing all three hydraulic systems caused crash. Use of engines is what prevented a total loss of life.


Ingestion of pigeons took out both engines.

What your list shows is that it takes a LOT to bring down a jet. Simple engine failure is just not enough.


Not even close. Just the ATR has more death toll that your examples put together.

That includes TransAsia Airways Flight 235 where the crew feathered the wrong engine which can't happen in a jet.

Mike C.

Not sure about that?

509 fatalities in just those three accidents.

ATR 72 total fleet wide fatalities 332

Are we comparing net to net or net to gross here?

Andrew

All turboprops are not the same
All pistons are not the same
All jets are not the same

Each airplane has it's own numbers. Each one is unique. You can't lump them into groups.

All turboprops are not the same
All pistons are not the same
All jets are not the same

Each airplane has it's own numbers. Each one is unique. You can't lump them into groups.

AA191 _lost_ an engine; it departed the aircraft.

What??

Bogus comment Mike C - once the ECO handle has been pulled it can't be reset. There have been many cases where the wrong one was pulled, isolating and ending hydraulics, fuel, bleed air and electrics with valves, doors and contacts.

Props CAN be unfeathered easily, and a re-start is likely. For the jet - not possible after yanking that handle. Look it up. All it takes is a faulty sensor to start the ball rolling.

Bob

You can't feather a jet engine.


Can you provide accident reports from such occurrences? I don't know of any such accidents myself.

The key distinction is that when the jet engine fails, you don't have to do anything to achieve the OEI performance, just fly it. When it comes time to secure the engine, that is done without significant time pressure and by checklist. Mistakes are made when people rush (witness TransAsia 235).


Citation II has a restart procedure, in fact three of them:

EMERGENCY RESTART - ONE ENGINE - STARTER ASSIST

EMERGENCY RESTART - ONE ENGINE - WINDMILLING

EMERGENCY RESTART - TWO ENGINES

What would make an engine shutdown in a Citation II irrevocable? I can't find anything in the AFM to indicate that.


Yeah, the TransAsia 235 accident was one engine falsely going into auto feather followed by the crew falsely feathering the other engine. Basically, they had two good engines and neither was providing thrust.

Mike C.