Arrow PA-28 Experienced In-Flight Break-Up

[sternone]

NTSB Says PA-28 Arrow Experienced In-Flight Break-Up

Tue, 13 Nov '07

Outboard Wing Sections Broke Off, Ailerons Also Separated

An airplane that went down in southwestern Utah in October, killing two brothers, broke apart in mid-flight, according to the National Transportation Safety Board.
The NTSB has released a preliminary report into the crash that killed Benjamin and James Timpson of Centennial Park, AZ. The single-engine Piper Arrow crashed the evening of October 26 near Colorado City, AZ.
According to the prelim, the airplane was flying from Bountiful, in Davis County, to Colorado City when it experienced an in-flight loss of control, broke up and then crashed into mountainous terrain about 21 miles southeast of Cedar City.
"The airplane was destroyed during the in-flight breakup and post-impact ground fire," the report said. "The entire instrument panel, cockpit and cabin were destroyed by fire, along with several acres of adjacent native vegetation on the mountainside, elevation 6,400 feet mean sea level."
An NTSB investigator examined the crash scene and noted the "outboard portions of both wings separated from the inbound span of the wings, which remained attached to the fuselage."
"The ailerons were found separated from the wings," the report said
The NTSB said recorded air data showed the plane left Bountiful at 6:15 pm on October 29, heading south toward Colorado City's airport.
"Thereafter, the rate of descent increased as the airplane reversed its course. The main wreckage was located about 1/3 mile from the airplane's last radar recorded position," said the preliminary report.

May they RIP... we might not know what happend, but no Arrow plane for me please...

[Kiltie]

Yes, be warned everyone; all Piper Arrows break up in flight, Mooneys of course never do.

[smarthawke]

Sternone

How about nipping off and getting some experience in the world of GA (flying and time) before posting such ridiculous comments.

Your posts are normally written as one of great knowledge but are normally flawed to those who know a tad more than you. I'm sure if you look you'll find Mooney's and cessnas and all sorts of machines that have suffered structural failure in flight - it doesn't necessarily mean that there is a design flaw or the aircraft is weak.

Perhaps you could go off and find out how many hours have been flown by PA28Rs without having the wings fall off.....

[yawningdog]

I remember reading about another Arrow that broke up within the last few years. The reasons given were that full control movement over stressed the airframe.

Just speculating, but if the weather was poor or IMC around rising ground, its feasible that this recent breakup could have been as a result of over stress due to over control. Ie: disorientation or panic.

Arrows are great aircraft. If there was an inherent structural problem with Arrows, it would be happening all the time as there are so many.

[The Nr Fairy]

yawningdog:

Well remembered. AAIB accident report (PDF) here.

[Contacttower]

we might not know what happend, but no Arrow plane for me please...

Arrows are perfectly safe provided they are operated within their envelopes and maintained to the right standard. But as you have said before (and I agree with you) they are not as solidly built as some aircraft and may once having departed its safe envelope prove more vunerable to inflight break up than say a Beech Bonanza.

Personally I think the PA28 is a great aircraft and has given many years of sterling service to the FTOs of the world. And as someone who has flown nearly all the PA28 models there are and have about 150 hours on them I feel qualified to comment.

[Tony Hirst]

One thought that struck me is the potential for a constant speed retractable gear aircraft to quickly exceed at Vne with the confusion that can follow a nose down unusual attitude. Although possible, the potential is generally substantially less with a fixed prop and fixed gear.

[sternone]

How about nipping off and getting some experience in the world of GA (flying and time) before posting such ridiculous comments.

Besides the fact that i feel sorry for these 2 unfortunatly pilots i would like to ask you, would it have been breaking up when it was a mooney or a beechcraft ? Maybe yes, probably no.

Hihi, Also i feel quit sorry for you that the only argument you can tell me is that i'm low houred not yet PPL rated.. comon, please do better than that, i could actually learn something from you guys.

[BackPacker]

Also i feel quit sorry for you that the only argument you can tell me is that i'm low houred not yet PPL rated.. comon, please do better than that, i could actually learn something from you guys.

Have you done the aircraft performance test yet? Because I think you don't give enough credit to this comment:

The reasons given were that full control movement over stressed the airframe.

All aircraft, without exception, have a Va limit, which depends, to a large extent, on the strength of the wing spar. In fact, in order to certify, the aircraft structure has to be strong enough to survive certain "g"'s at MTOM, and Va is a direct result of that. (For a normal category aircraft, I think the positive g limit is 3.8. Not a lot actually.)

If you fly faster than Va (and Va changes with actual mass) and apply full and abrupt control deflections, you will exceed the design parameters of the airplane. If you also exceed the safety margin that manufacturers built in, then you will break off the wings (or the tail section). Doesn't matter whether the aircraft is built by Mooney or Piper.

If you challenge me, I would be willing to take up a Mooney and demonstrate that it is indeed possible to fly its wings off. Mind you, I'd want to do an emergency egress course and a parachute free fall course first. But then I'd just dive a Mooney to Vne (or beyond) and pull up sharply. (On second thoughts, never mind.)

Edited to add that it's not uncommon to have a Va that is *lower* than the typical cruise speed. So even if you apply full and abrupt control deflections in the cruise, you might break the wings off.

[Mark1234]

i would like to ask you, would it have been breaking up when it was a mooney or a beechcraft ? Maybe yes, probably no

A conclusion reached how?? For my part, I'll say the answer is YES.

There's a design requirement to meet 50% more than design G loadings (so 5.7G) before failure.
[edit to add having flown a very few aeros 4+G is actually rather a lot to most pilots - really, it's not the sort of limit you just creep up on not realising! try it some day ]

The reported details give no clue as to *why*, however, exceeding those limitations, suggests loss of control in some fashion, however induced (or doing something really daft, but let's leave that).

If out of control, it's most likely that the aircraft would exceed whatever the actual limits of the airframe were, EVEN if there was a little more margin in other types than the arrow - there's nothing to suggest the outcome would be different in any type.

[yawningdog]

Don't worry about that comment sternone, that's the nature of forums.

I think its a good subject to raise, and anyone who hasn't flown much in Arrows might well be put off by an accident like this. But if there is anything to learn from the limited amount of information available here is that, excessive deflection of the controls above or around the max maneuvering speed could cause structural damage in almost any aircraft.

That doesn't mean you should be scared of performing steep maneuvers, you may need to perform some to avoid a collision or something. But be aware that there are limitations.

My understanding of the definition of max maneuvering speed is that full control deflection is not permitted.

[dublinpilot]

If I remember correctly the accident investigators, investigating the UK arrow accident, had to try extremely hard before they could get sufficient g forces to break the wing.

The took the cruise speed (which is above Va on an Arrow) and applied a sudden and abrupt full control deflection, but didn't get anywhere near the needed forces. So they then tried a sudden and abrupt control deflection from one extreem to the opposite, and got nowhere.

So then they tried a sudden and abrupt full control deflection in two axis, and got nowhere. Then they tried a sudden and abrupt full control deflection in two axis from one extreem to the other and got nowhere.

In the end, the only way they could break it was, a sudden and abrupt control deflection from one extreem to the other, in two axis, and then and instant full and sudden reversal back to the opposite extreme.

If you try hard enough you can break an airplane, but the Arrow is by no means an easy aircraft to break.

dp

[deice]

Sternone, I think that you're proving yourself to be perhaps a bit too interested in jumping to quick conclusions without any factual base at all, and unfortunately for you, you're conclusions and ideas are wrong, hence strong words from other posters. If you had elected to say, "this and that happened, would it have made a difference in a Mooney?" instead of offering completely outrageous remarks, then perhaps we would indeed be more inclined to teaching you a thing or two...

VA has been described and I'd like to add that for most aircraft it is indeed lower than cruise speed and many times much lower even. A Malibu for example cruises at 180 knots with a VA at 130 or so. That's a 50 knot spread. Have you checked the Vcruise/VA spread of a Mooney lately? It's about probably even greater as the VA for the M20 is around 130 knots and cruise is upwards of 200 knots.

I wouldn't call myself an experienced PA28 pilot with only about 250 hrs in them myself, but I'm pretty sure you need to pull some massive Gs at high speed to break anything off of them. But it can be done.
Many years ago there was a relatively spectacular crash with a Malibu in Sweden. They popped vertical out of a cloud heading for the ground and likely pulled themselves silly as they managed to break the tail off, which from testing takes a massive 9G load before failing! Piper knows their business no doubt.

[Brooklands]

and may once having departed its safe envelope prove more vunerable to inflight break up than say a Beech Bonanza.

The Bonanza isn't (or wasn't) exempt from in flight break ups. In its early years in V-tail form, it acquired the nickname The fork tailed doctor killer due to a number of in flight breakups.

As others here have said, if you take an aircraft outside its normal opertaing envelope and overstress it, then you shoulnd't be surprised it bits fall off.

Brooklands

[Mark1234]

As an aside, I believe it's far easier to break an aeroplane through overspeed than over-G - if my memory serves, VNE is only 10% less than max flight tested, rather than the 50% on G-loading. I may be thinking about sailplanes though, which I would expect to be more flutter prone than shortwing tin (and have higher G limits).

[IO540]

If you want a plane with no known case of in-flight failure, get a TB20

One thought that struck me is the potential for a constant speed retractable gear aircraft to quickly exceed at Vne with the confusion that can follow a nose down unusual attitude. Although possible, the potential is generally substantially less with a fixed prop and fixed gear.

Not sure I agree re the CS prop bit. A CS prop gives you better pitch stability, because IAS variations (due to pitch changes) do not translate into RPM (and thus fuel flow and thus thrust) changes.

The fixed gear is also a redherring. A slippery airframe will speed up more than a less slippery one. A Lancair is quite slippery despite its fixed gear.

However, this stuff can be well overdone. When I was looking at the TB20, I was still hanging around the flying school scene and the instructors were giving me dire warnings about busting Vne within seconds of pitching down. It's a complete load of b011ocks. The TB20 is a piece of cake to fly and one would have to totally lose it first to hit Vne accidentally, in a spiral dive of some sort. Otherwise, a nose down pitch just makes it speed up and then it wants to climb back again...

I do think the PA28 family isn't particularly sturdy but they aren't designed to be. They are slow plodders, flying mostly at ~ 100kt.

[BackPacker]

having flown a very few aeros 4+G is actually rather a lot to most pilots - really, it's not the sort of limit you just creep up on not realising! try it some day

True. I just finished an aeros course and the first few times I pulled 4g to enter a loop I scared myself to death. But it's becoming routine now. Just to the point where I feel I might be dangerous in a non-aeros plane...

Anyway, your comment reminded me about another story, which happened some years after WWII in a DC-3 or something. The captain on this regular commercial flight had flown the same type in the war. On this particular flight it so happened that one of his old war buddies was a passenger, and he was quickly invited into the cockpit for a chat.
While exchanging stories, the passenger quietly slipped the gust lock over the controls - a practical joke they played every now and then in the war on inexperienced flight crews.

When trying to correct a flight path excursion, the pilot would find his controls frozen leading to brief, hilarous moments. Only in this case, the pilot (now operating under a different SOP) did not correct the flight path excursion with the control column, but by adding a little downwards trim. A few seconds later the captain noticed that this did not have the desired effect, so added more trim. And more. And more. The passenger, seeing that his practical joke did not fly, decided at this point in time to remove the gust lock.

The results were horrendous. The aircraft all of a sudden pitched down with something like minus 1 or minus 2 gs. Both the captain and the passenger, which were not properly strapped in, were smashed against the ceiling of the cockpit. In the cabin the result was even more dramatic, with several cabin crew and passengers breaking limbs and getting cut.

The day was saved by the young co-pilot who had remained strapped in properly, and been keeping an eye on his captain. He managed to pull the aircraft out of the dive, reset the trim, adjust the throttles (which, in this particular aircraft, were mounted on the ceiling, where they met the captain on his way up) and get the aircraft back on its proper flightpath.

I don't remember the exact outcome, but I would not be surprised if the aircraft was bent beyond repair in the process anyway. (Wish I had made a bookmark on where the original story can be found...)

Edited to say that Google is your friend... http://www.airlinesafety.com/Unions/Sisto.htm I got some of the details wrong. Oh my.

[deice]

I do think the PA28 family isn't particularly sturdy but they aren't designed to be.
I know several mechanics that say the same about the TB, but I account it to their years of Piper/Cessna indoctrination. They take a beating from students and survive, so they're not that badly designed. We've had two accidents where the main gear poked through the top skin though so there may be some dinky bits in the design...
I know for a fact that our ex TB10 had its moments but in general was pretty nice. Having said that, the flying Citroen is no match in sturdiness against my ex mount, the Commander 114B. Talk about over engineering!! I believe they had aircraft carrier operations in mind when it was developed.
Is that a GT you're flying IO540?

[wsmempson]

So, just to recap some of the opinions voiced by Sternone on this thread and one or two other recent ones;

1. Piper Arrows are very dangerous because they are renowned for having their wings fall off.

2. DA42's are rubbish because there isn't a P1 armrest, and you have to endure your right arm in your lap.

3. Beech Bonanza's are great for getting in and out of short grass strips.

Those of us who actually fly these machines are learning something new every day.

[Fuji Abound]

When trying to correct a flight path excursion, the pilot would find his controls frozen leading to brief, hilarous moments. Only in this case, the pilot (now operating under a different SOP) did not correct the flight path excursion with the control column, but by adding a little downwards trim. A few seconds later the captain noticed that this did not have the desired effect, so added more trim. And more. And more. The passenger, seeing that his practical joke did not fly, decided at this point in time to remove the gust lock.

The results were horrendous. The aircraft all of a sudden pitched down with something like minus 1 or minus 2 gs. Both the captain and the passenger, which were not properly strapped in, were smashed against the ceiling of the cockpit. In the cabin the result was even more dramatic, with several cabin crew and passengers breaking limbs and getting cut.

Cracked me up, anyway.