Don't fly on light twins advises Air Passenger Association!

[Cyclic Hotline]

I'm afraid that although this might be headline grabbing stuff in this story, the comment it ends with is accurate in my opinion and is advice I stick by personally.


Cessna 402, Frequent Work-Horse of Small Charters

WASHINGTON (Reuters) - The twin-engined Cessna that crashed killing U.S. singer Aaliyah and eight others this weekend is a work-horse of small commuter operations and well known to pilots.

The Cessna 402, with two six-cylinder piston engines and seats for up to nine passengers, can be found ferrying people from New York to Martha's Vineyard or island hopping in the Caribbean.

Aaliyah's plane crashed into swampy scrub and burst into flames just beyond the runway at Marsh Harbor airport in the Bahamas after taking off for Miami.

Local police said the plane had apparently experienced engine failure as it took off but there were also reports that the aircraft was heavily loaded.

Light twin-engined, piston-powered aircraft have a reputation for marginal performance if an engine quits on takeoff with a high-degree of pilot skill required to land safely.

"If there's any truth to reports they were overweight and they had an engine failure -- then they were just out of luck," said a pilot with a major airline who spent 500 hours flying Cessna 402s while working his way up to jets.

"I didn't mind flying the 402," said the pilot who requested anonymity, "but that was a while ago and they're not making any new ones."

Cessna, a unit of Textron Inc., built 664 of the 402B series between 1973 and 1978, said spokeswoman Jessica Meyer.

The company no longer makes a light twin piston-powered plane. Taking its place in the market is the Cessna Caravan, powered by a single turboprop.

National Transportation Safety Board data show 49 people killed in 14 separate Cessna 402 crashes the board has investigated since 1996, excluding the Bahamas crash.

The only other fatal Cessna 402 accident so far this year was an April 26 crash of Texas Air Charters Inc. plane which hit the ground on final approach to Del Rio, Texas killing the pilot who was the sole occupant.

NTSB data shows fatalities connected to two other light twins, the Piper Seneca made by New Piper Aircraft and the Beech Bonanza, made by a unit of Raytheon Co., at 44 deaths a piece since the beginning of 1996.

"We advise our members not to fly light twins," said Air Passengers Association President David Stempler.

[AMEX]

Hi CH long time no see.
Here in the UK we have problems to get Single Engine Turbo-prop (SET) certified for commercial OPS.
I understand that it is a new concept and the aviationn indusrty being cautious, conservative and wishing to maintain the highest standards of safety, we are reluctant to change.
However, SET like the caravan have a much higher safety record than many light piston twins and it has become increasingly more difficult for the Authority to justify its opposing position.
Not wishing to quote any figure because it is all to easy to manufacture or use manufactured numbers, I would rather you to search carefullyy all the datas available from various sources. But this new generation of single engine seem to have a much better safety record for more than one reason.
- the reliablility of a turbo-prop engine
-the lower approach speed of a single engine
after its engine failed.
-No critical engine
-whatever you know better than me

I certainly woudn't go as far as suggesting that twin engine aren't safe (since the operator is mainly responsible for its maintenance), but I want to stress the advantages of what modern technology has to offer.

[BEagle]

Perhaps it's time to re-examine the twin engined centreline thrust concept? Something like a bigger, quieter Cessna 337?

[MasterGreen]

But is this a Vcrit / Assym handling problem or a power available (on one) problem. I would rather have thought the latter. Putting two inadequate motors on the centerline just means you hit the ground without yaw.

Remember the old Varsity / Valetta brief ".... and the remaining engine will carry us to the scene of the crash..."..

MG

[Cyclic Hotline]

I agree, that an adeqately powered modern version of the 337 would be quite a seller. Two PT-6's, and you would have a tremendous machine.

The current efforts in this arena, are all focused upon twin (combined) engines and a single prop. The problems invoved in certification and completion of the product, seem to be driving at least two organisations to the wall.

Soloy has been working on the Pathfinder for many years and seems no closer to certification of a marketable product than he was years ago. The position change of the FAA and Transport Canada, seriously impacted their sales potential. In order to continue with any kind of viability, he has had to continually grow the aircraft in order to provide some basis for an operator to select it over a straight Caravan. Of course the drawback to a design of this nature, is that it grows in complexity by virtue of the drivetrain combination, exposing it to a degree of failure unlike the (relative) simplicity of the straight C208 Caravan. http://www.soloy.com/

The other product is the Ayres Loadmaster, similar concept, but a new and bigger airframe. The company is so embroiled in simply staying alive, that it's future is very uncertain. http://www.ayrescorp.com/loadmaster.html

Amongst various types, I have operated 3 and 4 series Cessna's and would not do so again. I do however currently operate a Caravan and would rate it as simply the most reliable and predictable model (of any aircraft or helicopter) I have ever operated. I do not think the current position of the CAA reflects the evolution and progression of modern aircraft types - not to say there are not limitations to the aircraft; but simply the current certification status is short-changing the aviation consumer.

The old question of whether a single or twin engine aircraft is safer, in the instance of aircraft unable to sustain flight in all regimes on a single engine; comes down to the statistical probability that with 2 engines you are twice as likely to suffer an engine failure - and it's consequences!

On the topic of 337's, thought you might like to read this story! http://canadianaviation.ca/forums/ub...c&f=2&t=000431

[Basil]

During my air taxi days I noticed a cavalier attitude to weight displayed by one or two operators (you know who you are! and at least one of you no longer has an AOC - hooray!). Amongst other things, they used standard weights when carrying oil rig workers; I think about 80kg - for a rig man?
You should weigh pax and baggage or estimate their weight and use actual figures.

I was in the fortunate position of being able to refuse to operate illegally but not all pilots can so lightly tell the boss to shove it - so, yes, I'd agree - I wouldn't be happy to fly as pax in a light twin unless I knew for certain that I was dealing with a respectable company.

[HugMonster]

Overload any aircraft and you will have major problems if a donk quits.

I'm not sure if the article is claiming that any Perf C aircraft is inherently unsafe, and it has to be admitted that they're not as safe as a Perf A aircraft. However, once again, the paying public have to examine the safety=price equation. A higher margin of safety = a more expensive flight.

Certainly there are aspects of centreline thrust that make it preferable if operating one engine out. But that is very far from being the end of the story.

I have to admit that the C402 is not a very forgiving aircraft. I have known worse, however.

Once in Union Island (south end of the Grenadines), a mate and I saw a French-registered Caravan land from Guadeloupe. He expressed distaste at the idea of operating single-engine over water. I pointed out to him that the Caravan driver was in a safer potition that we were. My friend couldn't understand why. I pointed out that with two engines you have twice the possibility of one failing. Our aircraft's single-engine stabilising altitude was sea-level. So if we lost one, we were going in. He lost his, he was going in. However, he only had one, not two to give up the ghost. Plus, with the track record of different engines, I'd trust a PT6 to keep going much more than I would a Lycoming IO-540.

[Vsf]

1. I've never lost an 0-540. I have lost PT-6's; they're good, yes, but not *perfect*, contrary to some claims.

2. Light piston twins are borderline dangerous. They don't have to be able to climb out after an engine failure on takeoff. Yikes.

[HugMonster]

I've never lost a PT6 - I have lost an O-540. What does that prove? Not a lot. However, the PT6 is one of the best turboprop engines ever for reliability.

[Steepclimb]

I think we have to be careful, as ever about prejudging accidents like this.

Condemming light twins out of hand on the basis of this accident is a little unfair.
As usual if an aircraft is operated within it's limits by a current pilot, then you minimise the risks.

I read a news report today, quoting another pilot who overheard the pilot arguing with the passengers about the amount of camera equipment they were loading. Eventually apparently he gave in. I suspect the argument applied against him was that the aircraft that brought them in had no trouble carrying the load.
There was also a comment that he had trouble starting one of the engines. As anyone who has flown pistons (ie all of us, nearly)knows. Sometimes they don't like starting, it has no bearing on how they run. There is talk of an engine failure, but no one knows yet. It's all too soon.

People are jumping to conclusions.

[TowerDog]

H M:

I think the C-402 has 2 IO-520s made by Continental, not Lycs.

I memory serves me right, the Aztecs sport the 540s, but rated lower: 250 HP vs 300 or 325 for the 520s, depending on type of Cessna 402: B or C model.

The C-402s are good planes if ya don't push 'em as far as load.

Never flew the C-208 Caravan, but have a couple of thousand hours on the DHC-6 with PT-6s. Super engines IMHO.

[HugMonster]

TowerDog, you're probably right about the engine type in the C402. I don't know it well, but a company I used to work for in the Caribbean had one, on which I have a few hours.

As for Continental vs. Rolls Royce vs. Lycoming - basically, they're all the same family of engine. I don't want to be picky, but there are many versions of the PT6A as well.

My point was that, if you examine the records I am sure that you will find far fewer PT6A failures than you will on IO-520's, IO-540's, TSIO-540's, whatever.

The main drive of the article is that light twins ar per se unsafe. My contention is that sure, they're less safe than a Perf A aircraft, which is designed to be able to lose an engine at V1 and still get airborne, but also that any aircraft is unsafe if loaded incorrectly.

But if people only want the price of a C402 they're unlikely to stump up for a KingAir.

[ 28 August 2001: Message edited by: HugMonster ]

[Epsom Hold 2]

Perhaps this should be in the Questions forum but since it's on the topic, could someone please explain what the advantage of two engines is on a light aircraft? Surely the only reason for two engines instead of one is to take-off/initial climb after an engine failure - but if the aircraft isn't required to do this to get it's CofA, what is the advantage of the second engine (especially considering the increased - doubled? - odds of a malfunction)? Everything I've learned about light twins makes me quite nervous about getting back in my mate's Aztec; although I was onboard when he revalidated his Aztec type-rating and this included chopping an engine to zero thrust [forgive the probably incorrect terminology] and I couldn't tell when the engine was cut. This was performed twice very shortly after leaving the ground and we completed the circuit normally and landed both times.

To summarise, Can a light twin at max t/off weight climb away if an engine fails at the point of liftoff or not, and if not, what is the advantage of the second engine?

Thanks.

[HugMonster]

Epsom, a light twin (mostly they're in Performance Category C) cannot take off if an engine fails at takeoff. It can, however, continue to climb away if an engine fails at, say, 200' agl. (Thus goes the theory, and some of the practice.)

The mnemonic I was taught when losing an engine at that sort of height is based on the first word that comes to mind at such moments:-
Firewall everything
Undercarriage up
Correct the yaw
Kill the dead engine

Larger aircraft (those in Performance Category A) can still take off if an engine fails at V1, the most critical point of the take off roll.

Put simply, in a twin-engined aircraft, the joke is that the second engine will see you safely to the scene of the crash. That's a crude way of putting it, but the second engine will generally give you a far better glide ratio at worst, and at best you will be able to feather the dead propeller and fly yourself to a safe landing at a suitable airfield.

Depending upon temperature and pressure, the altitude at which you will be able to fly after an engine failure (the single-engine drift-down altitude) you get from a table in the Flight Manual for the aircraft.

For aircraft such as the Islander, in conditions found in the Caribbean, the above figure is sea-level. Therefore, if you lose an engine, you're going in. If you're significantly overweight, you're probably going to spin in. One is probably survivable. The latter almost certainly is not.

This is not to say, however, that there is anything significantly dangerous about flying in light twins (or any aircraft). Even in the case of a Piper Navajo a few years back in which the left engine decided it was bored with the company of its associated propeller and wished to lose it, when one blade went through the nosebay compartment, taking the entire engine on the opposite side off the wing, the pilot still managed to get it down.

[ 29 August 2001: Message edited by: HugMonster ]

[denachtenmai]

Maybe the companies that operate these twins should give Burt Rutan a call and find out when(or if?) the "Boomerang" is going to be certificated,from what I have read about it most of the handling problems of light twins have been overcome.Ref. Pilot Feb.1997
regards Dinsdale.

[N380UA]

No aircraft is really a problem ever. If the owner/operator is moving his aircraft beyond the operational limits set forth by the manufacturer and/or the crew is not as proficient as they perhaps should be, than these tragic accident may happen. Be it for the most recent crash or any yet to come. As we all are well trained in determining our W/B and judging the flight safe or not, we all know what to do during an engine failure, whether we operate an IO 520 or a PT6 has no influence. That something may go awry during a flight and technical installation onboard quit their service at no particular time of any operation is not new to the industry either. To ensure that those risks are minimized we fully and often regretfully rely on our regulatory authorities setting maintenance, flight and other operational parameters. Within those set standards, we should not be worried about the type of equipment being used, rather question the integrity of the operator should any doubts arise.

[aztruck]

I dont think the accident report is in yet is it? General observation about GA twins concerns the number of fatal accidents after engine failures. its important to separate the failure itself from the subsequent loss of control that usually kills everyone.
lose you one engine in a single and you have a glider which can be controlled down to ground level and dead sticked. if you do it right then people walk away, if not and terrain/water/night/bad vis intervenes then you are equally stuffed. people still lose control and stall/spin in singles even with the engine working.
i shut an engine down in a 400 cessna between greenland and goose bay and the aircraft was a perfect lady and behaved just like the book said drifting down from 230 to 7000 feet, but then again we were only 2 people and a load of rubber suits!
I believe that the 402c has 325 hp engines, down from the 375 horses on the pressurised C421 model. the 402 is unpressurised.
Max tow 402c is 6850lbs or6300 for a 402b
Maxzfw 402c 6515lbs or 6165 for the 402b(which also has only 300hp engines)
fuel burn at take off approx 300lbs per hour and then 200 lbs in the cruise.
I echo the sentiments above. Operate within prudent limits and stay safe.
nasty business. very sad

[rightbank]

Whilst there is no doubt about the theoretical reliability of turboprops, they are still at the mercy of their ancillaries. I once had to shut down a PT6 simply because a pipe came lose on the oil cooler and it lost all its oil and consequently its oil pressure. Even the most reliable of engines won't run forever without lubrication.

BTW, anyone any idea how long?

[Onan the Clumsy]

Would you care to explain a little more about those rubber suits?

[TowerDog]

Aztruck:

Agree on yer observations.
Been there, done that as well.

As for the accident in the Bahamas:

(From a legal stand point: This is pure fantasy and have no relation to reality, the following is all Bull Sh@t)

1) The C-402 was over loaded by 800 to 1000 pounds.

2) Most of the excess weight was aft of the CG.

3) The pilot was brand new, only second day at work and was not properly trained. (Read: Not trained at all: He came up North from a third world country claiming 3000 hours of flight time....)

4) The pilot did not have a current Medical Certificate.

5) The aircraft had a history of low fuel pressure on one of the engines. The company did not spend the money to replace fuel pumps.

6) The owner of this company will most likely go to jail. (Hope so)

Such a waste of human lifes.

Screw the cheap operators, if ya cant't do it right, get a paper route or whatever, just stay out of aviation.