bragi
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Tomahawk. Why does it have a bad safety record?

Thu May 06, 2004 11:37 pm

Hi all,

Does anyone know whether the Piper Tomahawk has particularly bad safety record? (one of the mechanics in my Flightschool refers to it as Traumahawk Wink/being sarcastic.)
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KYIPpilot
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Tomahawk. Why does it have a bad safety record?

Fri May 07, 2004 1:38 am

Try searching for tomahawks on the NTSB's site. Their records go back to 1962. You will be able to see what the cause of the accidents were.

http://www.ntsb.gov/ntsb/query.asp#query_start
"It starts when you're always afraid; You step out of line, the man come and take you away" -Buffalo Springfield
 
jwenting
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Tomahawk. Why does it have a bad safety record?

Fri May 07, 2004 3:07 am

Like all trainers they're used hard by inexperienced pilots.
That's bound to cause mechanical problems as well as crashes due to inexperienced handling.
Then there's a lot of flightschools that don't take safety (and especially maintenance) all that serious causing more problems.

I think if you take Cessna 150s and 152s you will find similar figures (though those are more docile aircraft which are more forgiving to pilot error).
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G4Doc2004
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Tomahawk. Why does it have a bad safety record?

Fri May 07, 2004 7:39 am

The Tomahawk had a bad habit of entering a deep stall due to the T-Tail design. The wings would blank the airflow to the tail, rendering it ineffective, and making recovery more difficult than should be for a trainer. Ask those who've flown a Tomahawk what the tail is doing even in a conventional stall.............it shakes and shudders quite a bit!! IT is a good flyer though if flown by the numbers and within the guidelines set forth in the POH.
"Failure to prepare is preparing to fail"--Benjamin Franklin
 
Illini_152
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Tomahawk. Why does it have a bad safety record?

Fri May 07, 2004 7:55 am

The certificaton testing the FAA did on the Tomahawk was done with a preproduction model built at the Lock Haven, PA plant. When that plant was destroyed, production was moved to Vero Beach, FL, but not before significant changes were made to the wing.

The new design included the removal of a number of ribs from the wing, reducing it's rigidity, and it was NOT put through new stall and spin testing by the FAA, despite being certified for intentional spins.

After a number of accidents and near misses involving spins, the NTSB reccommended that the FAA reevaluate the aircraft's performance in 1997
http://www.landings.com/_landings/ganflyer/jul25-1997/New-Tomahawk-Tests.html

FWIW, the Tomahawk's stall/spin accident rate is roughly 3 to 7 times higher than that of the 150/152, as discussed in this NTSB letter to the FAA-

http://www.ozaeros.flyer.co.uk/tomahawk/ntsb.htm

Interesting reading, I may fly one, but I sure as heck don't want to stall one, let alone spin one!

Added-
Another interesting read (if you have a spare day)
http://www.geocities.com/cfidarren/r-mccabe.htm
--
Mike

[Edited 2004-05-07 00:59:55]
Happy contrails - I support B747Skipper and Jetguy
 
stall
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Tomahawk. Why does it have a bad safety record?

Fri May 07, 2004 7:00 pm

I will follow my instructor's advice.

Don't fly in a Tomahawk, they have bad safety records.

Don't walk below a Tomahawk practicing spin recovery. There is a fair probability it won't get out of the spin. Period.

Fly safely.
Flying is fun
 
L-188
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Tomahawk. Why does it have a bad safety record?

Fri May 07, 2004 10:09 pm

Ah the Trama-hawk.

Never flown one, but knew a guy that trained on one, hated it.

One other thing, Piper was really big on marketing the "Laminar Flow Wing" on that aircraft. Which was one of the buzz words in the 1970's.

But how do you get a laminar flow section with round head rivits holding the wing together and prop wash over it  Confused
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QantasA332
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Tomahawk. Why does it have a bad safety record?

Sat May 08, 2004 6:06 am

But how do you get a laminar flow section with round head rivits holding the wing together and prop wash over it?

I don't know the Tomahawk, but if the round-head rivets are far back along the chord of the wing, them causing transition to turbulent flow isn't much of a worry. After all, depending on exactly how far back they are, they would be past the normal transition point of the wing. Usually flush-head rivets are used up at the front, but if this isn't the case on the Tomahawk, the laminar-flow airfoil wouldn't be accomplishing as much as possible, and consequently skin friction drag would be higher than necessary...

As for the stall/spin issues, again, I don't know the aircraft, but this might help...

Cheers,
QantasA332
 
flightsimfreak
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Tomahawk. Why does it have a bad safety record?

Sat May 08, 2004 3:28 pm

I did my private in a skipper, which is the brother to the traumahawk, and I liked it... I'm going to bed right now, otherwise I would go more in to it.
 
Mr Spaceman
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Tomahawk. Why does it have a bad safety record?

Sun May 09, 2004 4:27 am

Hi guys.

In an attempt to entertain myself, I decided to use a bit of the grey matter between my ears and study the NTSB accident reports for both the Piper PA-38-112 Tomahawk and Cessna 150/152's.

The following info isn't intended to compare the two different aircraft, especially since a total of 31,289 Cessna 150/152's were built and only 2497 Piper Tomahawk's were produced. Plus, I don't know how many of these aircraft are flying in the USA.

These are simply the facts listed in the NTSB reports and are based on a one year time period between May 5th 2003 and May 5th 2004.

During this time period there were 67 Cessna 150/152 accidents of which 10 were fatal. There were 9 Piper Tomahawk accidents of which 1 was fatal.

Here are the NTSB's preliminary accident reports for the Piper Tomahawk........

July 7/2003. Cause - Engine failure.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030710X01062&key=1

August 7/2003. Cause - Engine failure. (August 2003 was a bad month!)

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030811X01297&key=1

August 23/2003. Cause - Engine failure.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030829X01428&key=1

August 29/2003. Cause - Engine failure.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=20030911X01519&key=1

August 30/2003. Cause - Loss of control during takeoff.

http://www.ntsb.gov/ntsb/brief.asp?ev_id=1009X01700&key=1

March 2/2004. Cause - Precautionary landing.

http://www.ntsb.gov/ntsb/brief.asp?_id=0308X00290&key=1

March 18/2004. Cause - Crashed for unknown reasons. (Fatal)

http://www.ntsb.gov/ntsb/brief.asp?_id=20040325X00371&key=1

April 9/2004. Cause - Engine failure.

http://www.ntsb.gov/ntsb/brief.asp?_id=20040422X00497&key=1

April 25/2004. Cause - Crashed during takeoff for unspecified reasons.

http://www.ntsb.gov/ntsb/brief.asp?_id=20040428X00523&key=1

It appears to me that the accident on March 18, 2004 could have been caused by a stall/spin scenario.

The causes of these accidents are based on my own opinion. Big grin

This post is not an attemp to dismiss the "unpredictable stalling characteristics" of the Piper Tomahawk ...... which is well documented.

However, I am trying to point out that if you believe a Cessna 150/152 has a much better safety record than a Piper Tomahawk, well, unfortunately there's a lot of them going down too!


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[Edited 2004-05-08 21:46:12]

[Edited 2004-05-08 21:50:05]

[Edited 2004-05-08 22:02:34]
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SkyGuy11
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 9:44 am

Yeah, but we have no idea how many of each aircraft are flying today, and how many hours each model is flown.

Even if you assume all aircraft are still flying, the Cessna 150/152 has a much better record when using your numbers:

Cessna 150/152:
31,289 built
67 accidents = 1 accident per 467 aircraft
10 fatal = 1 fatal per 3129 aircraft

PA-38:
2497 built
9 accidents = 1 accident per 277 aircraft
1 fatal = 1 fatal per 2497 aircraft

Still, just about any airplane is as safe as the pilot who flies it.
.
 
sllevin
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RE: Tomahawk. Why Does It Have A Bad Safety Record

Sun May 09, 2004 10:17 am

In my opinion, issues regarding the Tomahawk are more an illustration of the failure of modern flight training than anything else.

As much as I like the 152/172/182, and PA-28's, the truth is, they churn out lousy pilots. Pilots who find they get away with sloppy flying, no problem. Feet on the floor? No problem! Slow feet during taxi? No problem! Not going through complete checklists? No problem!

Spin recovery without worry about details? No problem!

For modern trainers, it takes a significant effort to even GET them to spin, and typically, just releasing backpressure will end the spin. There's no real concern about setting trim, etc.

The Tomahawk, on the other hand, requires more attention to detail. If you don't follow the checklist before spinning (I believe that setting elevator trim to neutral is a require step, for example) you might just end up with a plane that doesn't recover from the spin. Such "touchiness" is not uncommon amongst aerobatic planes, however, it was new to the "modern era trainers" --although the ability to spin easily was at the top of the list of desired features when CFI's were surveyed during the Tomahawk's development.

All the other old wives tales about fewer ribs, etc., have long ago been disproved as urban myths. The Tomahawk was retested by the FAA and found to stall exactly as the prototype did.

To sum up, sadly, I attribute the Tomahawk's ailments to poor flying. Sadly.

Steve
 
liamksa
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 10:42 am

In my opinion, issues regarding the Tomahawk are more an illustration of the failure of modern flight training than anything else.

Interesting thoughts. I think a good basic aerobatics course should be mandatory for everyone training towards their PPL - and maybe even taking it a step further with some advanced training for commercial. Still it often comes back to $$ and probably 90% of people will have no interest/use for these skills during their flying careers.

I've done aeros (not much) in a couple of aircraft and the basic stick n rudder skills are priceless, as well as the confidence that you will be able to handle those abnormal situations should they come up.

One of the aircraft I did some spinning in was stable in the spin - once you got it there you get leave it spinning hands/feet off. And if you didn't use the correct recovery procedure you could find youself in a spin the other direction only the world spinning around you twice as fast. As you mention Sllevin the Cessna series is a very stable bunch of aircraft and i'd imagine (haven't spun a cessna) it would be keen to recover. I'm glad to have had these experiences - who knows how an aircraft not designed for aerobatics will handle in an inadvertent spin...
 
L-188
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 12:41 pm

As much as I like the 152/172/182, and PA-28's, the truth is, they churn out lousy pilots

Interesting point.

Back when I was flight training down at UND I specificly went for a class that was using PA-28's rather then Katanas. The reason why I felt the Cadet was a more realistic match for the Cherokee 6's that are often used for bush flying up here and what I thought at the time I wanted to fly.

There has been some debate for a while on wether a trainer should be "bite back" on mistakes if correct procedure is used or if they should be very forgiving. I think a lot of the people that go for the former are the same ones that lament the lack of taildraggers being used in training too.

Maybe the answer is requiring students to train in more then one type. A easy to hand aircraft for the basic instruction. Once they get the feel for that, transfer them over to a trainer type that will bite back more if it is mishandled.
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Illini_152
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 3:07 pm

While I'll be the first to lament the state of modern pilot training, where many of the young CFI's are coming from inbred training curriculums designed to create CFI's for that school, I digress.

There are certian aspects of the PA38-112's stall and spin recovery that are troubling enough that the NTSB wants them retested.

- The production aircraft was NEVER tested in stall and spin recovery by the FAA, the preproduction prototype was, but significant changes were made.

- The FAA conducts surveys each year for aircraft utilization, using these numbers, this is right from the NTSB: Using lower- and upper-bound estimates of flight hours, the PA-38-112 accident rate ranged from 0.336 to 0.751 fatal stall/spin accidents per 100,000 flight hours, compared to 0.098 to 0.134 for the 150/152. The Board concludes that the PA-38 has been more likely to be involved in these kinds of accidents than the 150/152

Between 1985-1994
PA38- 0.336 to 0.751 fatal stall/spin accidents per 100,000 flight-hours
C152/150- 0.098 to 0.134 fatal stall/spin accidents per 100,000 flight-hours


This is a SIGNIFICANT differance in accident rates.

- A Piper test pilot told the NTSB that stall recovery was "...totally unpredictable, one never knew in which direction they would roll-off, or to what degree, as the result of a stall." A second said that "...the airplanes were very unpredictable in a stall. Each airplane did not perform stalls the same from one flight to the other." These are brand new aircraft right off the line, not beat up flight school airplanes that are misrigged and full of hanger rash. A third test pilot, said that production aircraft were "nothing like the article certified [by the FAA] as far as stall characteristics are concerned." And that Piper test pilots who performed post-production flight tests were "shocked at the stall characteristics observed"

When a test pilot is telling you that the plane does not have predictable stall characteristics, THAT is a problem. There is NO record of the FAA ever testing production aircraft. They tested a single preproduction aircraft built in Vero Beach, all of the production aircraft were built in Lock Haven, PA after significant engineering changes were made to the structure of the wing.

And then there is this from the same letter:

In addition, the former Piper chief test pilot interviewed by Safety Board staff in January 1997 described a PA-38-112 "flat spin" that he experienced in 1983. He stated that during an intentional spin, after approximately 2 turns, the nose started to rise to a more level pitch attitude, the rotation rate increased, and the spin "went flat." He said that even with full recovery rudder and elevator control, the "flat" spin continued for at least two more turns; then the nose slowly dropped and rotation ceased. He described the experience as "frightening. I didn't think that it was going to recover."

In April 1991, an FAA inspector from the Rochester, New York, flight standards district office was administering a check ride to a flight instructor from a 14 CFR Part 141 flight school in a PA-38-112. The FAA inspector had about 13,500 flight hours and had served as an aerobatics instructor; he had reportedly performed numerous spins in at least 15 different airplanes, including many spins in the PA-38-112. As part of the required check ride maneuvers, the inspector asked the candidate to perform a 1-turn spin to the right at an altitude of 5,000 feet. The candidate placed the airplane into a spin; however, the nose began to rise and a flat spin developed.

According to the inspector, the candidate immediately attempted to recover from the spin using the recovery procedures described in the airplane flight manual, but the airplane continued to spin. The inspector then took control of the airplane and described moving the flight controls to maximum deflection with no response. In desperation, the inspector released his seat belt, pulled himself fully forward against the instrument panel, and instructed the other pilot to do the same (a maneuver which the inspector credits with saving their lives). After several more revolutions, the nose of the airplane dropped and a recovery was effected. Control of the airplane was regained less than 1,000 feet above the ground. After landing, the airplane was immediately inspected. No discrepancies were found and it was determined that the flight control rigging, weight and balance, and configuration of the airplane all complied with the airplane certification.


I'm not saying the Traumahawk is an unsafe airplane. I am saying I wouldn't want to stall one though below 3000', or spin one without a parachute and quick release doors.

--
Mike
quoted from previous link
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L-188
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 3:15 pm

Well here is another question.

How does the stall characteristics of the Tomahawk compare with the simularly configured Beech Model 77 Skipper?




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Illini_152
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 4:13 pm

How's this:
http://www.ozaeros.flyer.co.uk/tomahawk/tomahawk.htm

Dr. Kroeger -- the primary designer of both the Tomahawk and the Beech Skipper -- designed two strikingly similar airplanes: Both have T-tails and O-235 Lycoming engines. Both use the GAW-1 airfoil, have bubble canopies, are comparably sized, and have max. gross weights of 1,670 and 1,675 pounds respectively. Both have very similar mission profiles and are targeted for the same piece of the aviation market.

As I recall from that page, it goes on to cite numerous studies from AOPA's ASF and other publications, one shows the stall/spin accident rate for Tomahawk is twice as high as the stall/spin accident rate for the Skipper. Amazing, given their similaraties in initial design. As I recall, the marketing department got ahold of the plane before it went into production, but after certification, and removed some of the ribs in the wing. This reduced it's rigidity, and allowed for more oil-canning, which can effect the shape if it's airfoil enough to change it's spin recovery.

I'm pretty sure that's burried in that article, it's been a few years since I've read it in full. There has to be some reason why the accident rate is so high for that airplane.
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Illini_152
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Sun May 09, 2004 4:23 pm

Found it, in a press release dated 3/14/97 from Dr John Lowry (author of "Performance of Light Aircraft")
...The NTSB accident report and photos subsequently obtained from NTSB General Counsel document that the prototype aircraft was in fact modified to a T-tail configuration. The engine was in fact modified to 112 HP. Piper Flight Test Report FT118 (see Attachment A) shows that this T-tail, 112 HP experimental prototype was indeed the aircraft used for the spin certification tests. This particualr aircraft had several aerodynamic enhancements that made it very nice to stall and spin, and FT118 reflects its good spinning characteristics.

Some of the aerodynamic features found on the experimental prototype and later altered by Piper's production team included a reduction in wing ribs from eleven on the prototype to four in the production models. This also included a lightening of the wing spar structure. Wing skin thickness was reduced as well. Combined with the rib and spar changes, this made the wing subject to flexing and oil canning, which causes a variable lift-drag ratio and noticeable variations in stall spin behavior. The wing root glove, vertical fin off-set and engine thrustline angle were changed. These changes, the original designer told NTSB field investigators, made the airplane unpredictable when flying near stall speed and especially during an intentional spin.

No stall spin certification tests for the two conformity (production) aircraft have been provided by FAA or NTSB.



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MD-90
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Tue May 11, 2004 9:38 am

The Skipper's a Beech, and of course it flies very nicely. No problems that I've ever heard of.

L-188, although of course the whole Cherokee/Archer/Warrior line all have extremely gentle stall charactistics. But they do handle a lot like Sixes (or so I've read, I've never flown a Six).

And I find it funny that anyone considers the 172 or Cherokee a modern trainer. Modern compared to what? A Cub? An Aeronca? To me, 'modern' aircraft would be a Cirrus, certified Lancair, Katana, Star, etc. Anything after the drought of the 1980s (excepting the new old Cessnas).

For the safest light aircraft, Consumer Aviation examined the data and found it to be the simple 172. The Katana was extremely close, in fact, almost tied, but the 172 fleet is so much larger that the comparison loses some validity. The 182 had a pretty good record as well.


If you're really concerned about the stability of aircraft in flight training and the possible laziness it could encourage, take some acro training. My mother says that the best training she ever got was her 10 hour aerobatics course in both a Citabria (150 hp) and a Super Decathlon (180 hp).
 
PPGMD
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Wed May 12, 2004 4:24 am

For the safest light aircraft, Consumer Aviation examined the data and found it to be the simple 172.

I remember hearing (you know second hand stuff you talk about at the airport) that the 172 is so draggy, that it hard to even get it past Vne.

Now the 152 though it's stall exit is not so graceful you practically have to force it to stay in a spin.
At worst, you screw up and die.
 
QantasA332
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Wed May 12, 2004 11:38 am

I remember hearing (you know second hand stuff you talk about at the airport) that the 172 is so draggy, that it hard to even get it past Vne.

Is it really that draggy compared to other aircraft of its class? I happen to have the Cdp (parasite drag coefficient) and flate plate area figures of some singles like the 172, and it (i.e. the 172) is not really that bad. Granted, induced drag is excluded, but I still doubt that it's really that much out of the ordinary...

Cessna 152: Cdp = 0.038, F. Plate Area = 6.14 ft²
Piper Tomahawk: Cdp = 0.054, F. Plate Area = 6.64 ft²
Beech Skipper: Cdp = 0.049, F. Plate Area = 6.36 ft²
Piper Warrior: Cdp = 0.034, F. Plate Area = 5.83 ft²
Beech Sierra: Cdp = 0.034, F. Plate Area = 5.02 ft²
Mooney 201: Cdp = 0.017, F. Plate Area = 2.81 ft²
Piper Arrow: Cdp = 0.027, F. Plate Area = 4.64 ft²
Cessna 182: Cdp = 0.031, F. Plate Area = 5.27 ft²
Beech Bonanza: Cdp = 0.019, F. Plate Area = 3.47 ft²
Cessna 172: Cdp = 0.036, F. Plate Area = 6.25 ft²

Again, the lack of induced drag figures means the above is definitely not a completely accurate comparison, but it's okay...

Cheers,
QantasA332
 
Illini_152
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RE: Tomahawk. Why Does It Have A Bad Safety Record?

Wed May 12, 2004 10:35 pm

I was going to say, I've heard that statement attributed to the J3 Cub, the Stearman, and a host of other biplanes. The Skyhawk will most definatly exceed Vne in a dive.

The Cub, OTOH, in a 30 degree dive at the ground with power still struggles to make it to 80 mph. And the Stearman, from what I understand is even worse (though I've never flown one, so I have no first hand experience.)

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