Seaplane down

[GusNSpot]

@Johnny L.A.

Link.

Exactly the one I thought of also.

My older sister got her Multi-sea rating in on of These…

[Terminus_Est]

What’s the difference between a float-plane, seaplane, and flying boat?

[Johnny_L.A]

A seaplane is an airplane that is capable of taking off from and landing on water.

A float plane has ‘floats’ – i.e., pontoons – attached in place of the wheeled landing gear. Floats may or may not be aomphibious, i.e. equipped with a retractable undercarriage for use when landing on land.

A flying boat is an airplane with a hull-shaped fuselage instead of floats. Flying boats may or may not be amphibious.

[Robot_Arm]

A seaplane is any airplane that can take off and land on the water. A flying boat is a seaplane where the fuselage directly contacts the water, and the airplane is designed from scratch to operate that way. A float plane is a regular, land-based airplane that has had large, external pontoons fitted to it. The Grumman that crashed was a flying boat, the last two links posted in this thread are float planes.

You’ll also see some referred to as “amphibious”, which means they have retractable wheels and can operate from water or land. And if you’re coming in for a water landing, don’t have the wheels down; that would be bad.

[JRDelirious]

And down a couple of blocks from where I work I could catch a flight on one of these.

[Robot_Arm]

No thread on oddball, twin-engined floatplanes would be complete without this, and this.

[N9IWP]

Pix of the spar crack
http://www.aero-news.net/news/commair.cfm?ContentBlockID=c80da6c0-8485-4555-a540-b5453a57905f&Dynamic=1

Brian

[Richard_Pearse]

@Johnny L.A.

Link.

Ja, ok. Obviously just a quirk of where I live that the floats are singles and the flying boats are twins!

Another reason to favour a flying boat over a float plane is that they presumably have less drag and therefore go faster for the amount of fuel used. Some float planes have a heap of drag hanging under them.

[Beware_of_Doug]

@ElvisL1ves

My understanding is that all scheduled-passengers-for-hire aircraft in the US have been required to be multi-engined since the 1930’s.

True. This regulation was put in place in 1934 after some spectacular crashes involving single-engine passenger craft, notably the fast Lockheed Vega family. (Federal favoritism toward the big players in the industry – Boeing, Douglas, and their main customers United and TWA – might also have been a factor.)

[GusNSpot]

A float plane is a regular, land-based airplane that has had large, external pontoons fitted to it.

And their are always exceptions.

Grumman Duck

Some of the 1930’s air racers were also pontoon birds…

[ElvisL1ves]

@N9IWP

Pix of the spar crack
NTSB Releases Images Of Fatigue Cracks In Chalk's Wreckage | Aero-News Network

Brian

Thanks. That is as textbook a picture of a fatigue-crack surface as I’ve ever seen. I’m impressed that it went nearly entirely through the spar cap before changing to pure rupture - that wing had what they thought was a huge safety factor when designed, but crack growth behavior wasn’t well known back then (and it’s still a problem).

[medstar]

I’m not sure where I got this from but I thought I saw on CNN where an eye-witness claimed to see someone in the cockpit struggling with his seatbelt and was trying to get out. Is it possible that there was at least one survivor?

[N9IWP]

Not surprisingly, the FAA has issued an emergency AD (Airworthiness Directive)
http://www.aero-news.net/news/commbus.cfm?ContentBlockID=eaae6ea7-2a10-4dae-b0f2-5c340afd4a6c&Dynamic=1

Brian

[ElvisL1ves]

@medstar

Is it possible that there was at least one survivor?

Unfortunately not.

[Anne_Elk]

From the AD;

This particular airplane was operated in passenger service and in a salt-water environment. The airplane had accumulated over 31,000 total flight hours and over 39,000 total flight cycles.

That’s a lot of hours. I don’t know what total flight cycles are, I assume one cycle would be the stress of one complete flight. How many hours or cycles will a 747 or 777 airframe fly until it is retired?

[Richard_Pearse]

From an NTSB article about TWA 800:

@NTSB

Vannoy said there is no life limit on 747s, although older ones need additional costly maintenance. He said the first 747s entered service in 1970 and had a design life of 20 years, 20,000 flight cycles and 60,000 hours, but while airlines are still using the planes, they need extensive maintenance after the 20-year mark. Vannoy said 380 of the planes have over 60,000 hours, 240 have been in service over 20 years and 95 have more than 20,000 flight cycles.

The accident 747 had 18,000 flight cycles and 90,000 hours. It had scheduled inspections at 13,000 and 16,000 cycles and was due for another at 19,000 cycles. James Wildey, an NTSB metallurgist, said there is no evidence of any fatigue cracking in the accident 747.

Note that aircraft such as a B747 will have low cycles and high hours due to the length of flight normally taken.

[GusNSpot]

Up until an idiot crashed it, a company I worked for had the highest time on record, Cessna 140, It had over 34,000 hours on the airframe. It was a pipeline patrol bird. The boss had it in semi retirement and then a new pilot down in East Texas messed his regular C-150 up and was using it while his was getting fixed.

He died in the crash. Had he lived, I think the boss would have killed him anyway.

[N9IWP]

Back on the subject of large float planes, I have to link to this. Note that the date is NOT April 1.

http://www.spectrumwd.com/c130/articles/float.htm

Brian

[ElvisL1ves]

@Anne Elk

I assume one cycle would be the stress of one complete flight.

Right. The critical failure mode is fatigue, which is caused by the number of loading cycles as well as their magnitude. One loading cycle for a wing spar would be one flight. For a jet engine with a thrust reverser installed, one flight is actually 2 cycles, since pressure/temperature/speed goes back up to maximum during reverser deployment.

There’s a DC-3 still soldiering on with something like 94,000 hours on it. Fuselage fatigue, normally the limiting area, isn’t an issue because it isn’t pressurized.

[N9IWP]

NTSB preliminary report (nothing new)
http://www.ntsb.gov/ntsb/brief.asp?ev_id=20060106X00018&key=1

Brian