RNZAF Skyhawk Hours Flown?

[xr6turbo1]

I have read that the RNZAFs Skyhawks were the highest timed airframes in the world when they were retired.
Does anyone have the hours that individual airframes flew as it would be interesting to know? ;D

[corsair67]

I think the Skyhawks all had something along the lines of between 5500-6500hrs each.

I'm sure that Don, Calum or Phil would have a better idea for sure.

I did read somewhere the definite hours for some or all of the fleet, but I can't recall where just at the moment.

[Calum]

Don will know

[Dave Homewood]

Something I am more interested in is the number of hours our Hercules have flown. In the video on the 50th Anniversary of No. 40 Squadron made 11 years ago it stated that they were the highest houred examples in the world. A lot more hours must have been added since then.

[Calum]

Considering they were the first C-130H's built it's not surprising.

[skyhawkdon]

I have the final Skyhawk hours, landings and arrested landings at home in a spreadsheet. The airframe hours range from 5,000 odd up to over 8,000. I believe many of the USN TA-4J's were over 9,000 hours when they were retired, so no the RNZAF wasn't the fleet leader in hours on the Skyhawk.

[Dave Homewood]

That's still a lot less than I expected after 30 years continuous service. Interesting stuff.

[corsair67]

Don, will you be adding those details to your book? I think that kind of stuff would be interesting to some of us aviation 'nerds' out there: I know I'd love to see that kind of detail.

I guess for airframes that were are 30 years old, 5000-8000 hours aren't too bad actually.

[flyjoe180]

Short but hard lives i suspect.

[skyhawkdon]

Yes I intend to put that table of data into the book.

8000 hours for a fighter/attack aircraft is actually a lot. It says a lot about the ruggedness of the original Skyhawk design that they got anywhere near that figure given the environment they mostly operated in (maritime low level ops). There wouldn't be too many other aircraft types in the fighter/attack category that can claim those sort of hours!

I understand that originally Douglas designed the A-4 to have a 3000 hour fatigue life, but it soon became apparent that it was much stronger than that. The USN did a lot of fatigue testing to determine what its fail safe life was, particularly for the wing. This was the weak point in the airframe. So long as the wing was refurbished/replaced about every 4000-5000 hours it was good to go for another 4000-5000 hours.

The fatigue index for a fighter/attack aircraft is significantly different to say a C-130 or B757. Skyhawk fatigue life was measured by a number of usage factors, including flying hours, sortie profile (ACM has a much higher fatigue rating than say transit flying), post flight fatigue meter G readings, landings (including touch and go's), arrested landings and catapult launches (an arrested landing is the equivalent of 3 normal landings and a cat shot 5 normal take offs - in terms of fatigue life). The ex RAN A-4G aircraft came to the RNZAF with significantly less flying hours than the original NZ A-4K's but they had a lot more arrested landings and cat shots under their belt.

Other factors such as what under wing stores/weapons were carried, over stresses, accidents and heavy landings also significantly add to the cumulative fatigue on an airframe. It is a very complicated calculation and one that the RNZAF struggled to come to grips with. Towards the end of their service there was much discussion in RNZAF Engineering circles on what was the safe fatigue life of our Skyhawks. The short answer was the RNZAF didn't know! Structural changes to the airframe during Project Kahu had changed all the original Douglas calculations. The wing refurbishment programme which happened at the same time as Kahu also changed things (basically it zero lifed the wings but didn't change the airframe fatigue index). Prior to the F-16 deal the RNZAF had engaged a US organisation to calculate the remaining fatigue life of each air fame. Some work had been done, including fitting strain gauges to at least one airframe. But when it was announced we were getting the F-16's work on this stopped. It was restarted after the F-16 deal was canceled but didn't get far before Helen did her dirty on us.

In my opinion there is a large question mark hanging over the remaining fatigue life of these aircraft. Corrosion is another serious issue which reduces the total fatigue life and the RNZAF had some major issues with stress corrosion in the aft fuselage. In late 2000 the frame that holds the fin on (known as the 414 frame) was found to be seriously corroded and cracked on most aircraft (a number were grounded it was that bad). A replacement program had started but I think only half a dozen aircraft (if that) had had the frame replaced by the time it all came to an end. There were also no more new frames to be found anywhere in the world and the RNZAF was going to have to get new ones made for the rest of the fleet. Whoever buys the aircraft will have to deal with this wee problem! I could go on but I had better get back to work! Suffice to say the airframes have issues...

[corsair67]

Don, that is interesting to read about all the engineering (and mathmatics!) involved in trying to keep a 30+ year old airframe in the air safely, especially well beyond its designed life expectancy.

I don't think I'll buy one of the RNZAF Skyhawks as a warbird anymore! ;D

Really looking forward to your book, Don.

[corsair67]

This is a 'little' off topic, but I think this article from the USAF News Service makes for interesting comparision:


Two F-16s reach milestone

by 1st Lt. Adrienne Stahl
332nd Expeditionary Aircraft Maintenance Squadron.

7/29/2006 - BALAD AIR BASE, Iraq -- Two F-16 Fighting Falcons assigned to the 421st Expeditionary Fighter Squadron passed 6,000 flying hours during two recent Operation Iraqi Freedom combat missions over Iraq.

Flown by Lt. Col. Mark Cline, 421st EFS commander, and Capt. Nick Edwards, aircraft numbers 88-0471 and 88-0428 were the first Block 40 F-16s to achieve this milestone in combat.

This accomplishment is rare, officials said. Only one other Block 40 F-16 in the Air Force inventory has reached the 6,000 flying-hour mark.

Designers of the F-16 forecasted the aircraft design life to be 8,000 flying hours, according to Lockheed Martin officials. However, Air Force officials expect the F-16 to be in service beyond the year 2020, taking the jets beyond 8,000 flight hours.

Aircraft 88-0428 was accepted into service in September 1989 and aircraft 88-0471 was accepted in January 1990 and assigned to the 388th Fighter Wing at Hill Air Force Base, Utah, ever since. Both were deployed in support of Operation Desert Storm, four times in support of Operation Southern Watch and three times in support of Operation Iraqi Freedom.

The crew chief on aircraft 88-0471 is Senior Airman Trent Nelson, with assistants Senior Airman Jason Wall and Senior Airman Tom Manues. The crew chief on aircraft 88-0428 is Senior Airman Victor Alvarez with assistant Senior Airman James Speicher.

“It is an honor to crew such a great jet, especially doing what she was made for here in a combat zone,” Airman Nelson said. “It’s a great feeling to crew the flagship and launch Colonel Cline for a milestone like this, but it’s just the pride of the squadron taking care of business.”

Upgrades and improvements to the engines and parts of the jets through the Service-Life Extension Program have helped extend the life of these aircraft, said Capt. Mark Sloan, 421st Aircraft Maintenance Unit officer in charge.

For these jets to have reached this milestone is a testament to the maintenance professionals who work these jets every day, said Chief Master Sgt. Dave Edwards, 421st AMU noncommissioned officer in charge.

"I've seen these jets roll over the 3,000, 4,000 and 5,000 flying hour mark, and the incredible thing is that after all these hours, they are flying as well today as they did when they were accepted off the production line," the chief said. "The reason these jets have performed this well, for this long, is the blood, sweat and tears the maintainers pour into these aircraft."

[skyhawkdon]

Photo of a new 414 frame installed in the tail of one of the RNZAF Skyhawks. The new frames came from the Israeli Air Force. RNZAF Official photo


And what the old frame looked like after 30+ years service... RNZAF Official photo

[skyhawkdon]

The RNZAF also celebrated Skyhawk thousand hour milestones. This photo was taken at Perth in late 2001, just before the 2 Sqn A-4's returned to NZ. The aircraft is NZ6213 and the pilot is CO75 Wing Commander Nick Osbourne who was assisting 2 Sqn complete its final deployment in Australia.


This one shows the cake made for NZ6209 when it clocked over 8000 hours in 2001 (the first RNZAF A-4 to reach this milestone). Again it was celebrated by 2 Sqn while on deployment, this time in Darwin.


The pilot was CO2 Sqn Sqn Ldr Jason Easthope. Note his 9mm pistol clearly visable. When flying in northern Australia or SE Asia RNZAF A-4 poilots always carried a pistol and 2 full magazines!

[skyhawkdon]

The lowest hour RNZAF A-4 is NZ6218 with 5594.1 hours on the clock (it had 5 years off after its roll over at Townsville in 1985 so was way behind the rest of the fleet hours). 18 was the first RNZAF Skyhawk to go into storage at Woodbourne in 2001, making its last flight in RNZAF service on 15/8/01 (it was due for a Group servicing so was flown there in anticipation but it was never completed due to a Gov't decision to not do any more major servicings on the aircraft).

The highest hour A-4 is NZ6205 with 8079.3 hours on the clock. It was the final Skyhawk to be flown into storage at Woodbourne, making its last flight in RNZAf service on 30/7/04. It was also the last A-4 to have a Group servicing carried out on it by Safe Air at Woodbourne in 2001. The aircraft was retained at Ohakea as a demonstrator aircraft until 2004.

[xr6turbo1]

Thats some good info, I saw 05 fly into Woodbopurne on its last flight, a low pass that I will remember thats for sure

Can you tell me where and what Nick is doing these days?

[skyhawkdon]

Last I heard Oz and Easty were both still in the RAAF flying Hawks. My info could be a bit out of date by now though. Maybe Barnsey can update us on what they are doing now.

[corsair67]

Here's a photo of some 3SQN Hornets taken during the Red Flag exercises in the US in February, and the second aircraft from the camera may indicate where Easty is now:

www.defence.gov.au/media/download/2006/feb/20060220/20060207raaf8159336_06_033.jpg

[Calum]

I'd say you're right Craig :-)

[Dave Homewood]

Oz must be getting on a bit now. He was in the RNZAF when i was at school, and he appeared on the cover of North and South. Great article, it was one inspiration that made me want to join, along with several others. I recall Oz from the Wigram days when he instructing was at PTS or CFS, and was one of the Red Checkers pilots. A good guy from my experience.