QANTAS-no reverse thrust-economics

[shogunsina]

well,SIA still preaches not to use rev; beyond idle,brakes(carbon) are cheaper to replace.
and yet airlines in the gulf,where hot days are no good for brakes,use reverse thrust and brakes.
AS LONG AS THE NOREVERSE AIRLINES DON'T END UP IN THE BUSH OR DRINK,ITS OK FOR NOW,?????

[Miles High]

I read in FI that the investigatory authority (ATSB)have criticised QANTAS severley ('slammed' them actually), over their policy of no reverse thrust(well, idle only) and 25 flap - both cost cutting measures.

I wonder though whether the crew has discretion to not comply with this - surely landing in such conditions would mean using full flap and rev thrust? (Even without the benefit of hindsight!).
I'm not a heavy pilot so if anyone knows better please say. If anyone knows knows exactly what the Qantas policy is and whether there are exceptions or not I'd like to know.
Thanks.

[exeng]

I heard a rumour that the 747 was technically a 'write off', but QANTAS elected to repair it in order to preserve their hitherto untarnished record of no jet hull losses.

Regards
Exeng

[crl]

Miles High...
Under those conditions, it's pretty common to elect using Flaps 25 for landing in order to allow higher speed additives countering the gust factor; especially so if the landing weight is high. Though selection of higher Autobrake setting should be done and definitely using FULL reversers for the landing roll. It's a pity that the 2 chaps were caught in those situations and skidded for such long distance; must have been a real fright....

[scanscanscan]

The runway which experiences monsoon rain is not ridged or well drained or monitored by the airport authority for brake action.
The aircraft was operated in defiance of the manufacturers recommendations. So sue who you like, maybe both. Thats why the pilots got off ,to keep it all out of court.

------------------
We will do the drill according to the amendments to the amendments I er think?

[Airbubba]

In this famous picture of QF1 on the golf course the reversers aren't even cracked, guess they were saving the engines...

http://www.airdisaster.com/photos/qf1/3.shtml

[Wino]

Think about that crash, and then think about the A380 having reverse on only 2 of 4 engines. So they wont even have idle reverse available, 2 engines will always be making forward thrust...

CHeers
wino

[gaunty]

Guys if you care to pay a visit Dunnunda there is an interesting thread running there on the QF1 BKK story.

[crl]

AirBubba..
Interesting view for the photo taken on the slide, I guess no one tried getting out from Upp deck RH door... Cheers

[Capt. XXXX]

As I understand it, reverse thrust doesn't make a lick of difference to braking distance, especially when you select Autobraking, as this is simply a set rate of deceleration. Now when you use reverse thrust, the autobrakes must release an amount of braking to compensate for the retarding action of the reversers, and to maintain that same constant rate of deceleration. The brakes then reapply later in the landing roll after the reversers are cancelled. As carbon brakes wear based on the number of applications, as opposed to the intensity of the application (like steel brakes), I thought this was the economic theory behind not using reverse?

[Airbubba]

>>As I understand it, reverse thrust doesn't make a lick of difference to braking distance, especially when you select Autobraking, as this is simply a set rate of deceleration.<<

Well, I understand it a little differently, especially on a slick runway. I'm of the opinion that reverse will give you deceleration even if the wheels have little or no traction as with a wet runway at BKK. Boeing doesn't endorse the idle reverse procedure but maybe it saves money if you don't run off the runway. Still, $100 million will buy a lot of engine time...

Of course, the QF1 accident had the classic reversed decision to go around, another no-no according to Mister Boeing and most airline ops manuals. "Watch this..."

[mustafagander]

Capt XXXX
I sincerely hope you NEVER need to land or RTO on a slippery runway. To say that reverse "doesn't make a lick of difference" to stopping on a slippery runway indicates to me that you failed to grasp the content of braking performance on wet/icy/contaminated runways.
On such a runway reverse thrust is often ALL the retardation you've got until you slow below the hydroplaning speed.
On dry runways you're right, autobrake modulates to achieve a chosen level of deceleration.
Do yourself and your passengers a favour - master the theory of stopping on slippery runways before further flight.

[Capt. XXXX]

Gee, thanks for the performance lesson fellas! I thought we were talking about the economics of idle reverse versus normal reverse, as the thread started, not contaminated runway performance, but thanks for stating the obvious anyway.

Cheers

[prez]

I spoke with the FO on that flight a couple of months ago in Singapore. Here's how he described it.

Vectored for 21R in Bangkok. Thunderstorms in the area. FO is flying. Captain is a Training Capt. They past through the final. Asked ATC because they thought they'd been forgotten. Bangkok immediately changed the runway to 21L and gave them vectors. Before they switched frequencies, another Qantas 747 initiated a go-around on tower freq due to heavy rain. The crew landing on 21L never heard it.

On final with increasing
rain and decreasing visibility, Captain asks FO, "You alright?", or something to that effect. FO says yes. 100ft RA things are bumpy and visibility is reducing further. Heavy rain. It's a handful, but FO has control and is going to land. Captain again asks FO if he's alright. FO, might not have said anything. FO decides to initiate a go-around and announces his intentions. The wheels touch down and the throttles start tocome back to idle. The Captain
overrides the FO and brings the throttles to idle. #'s 2, 3, and 4 come to idle but #1 is still at TOGA. FO still has it. He brings #1 to idle, but he's having trouble keeping it straight and luckily the aircraft doesn't go off the side of the runway. Because of the Qantas reverse thrust policy, they don't use full reverse, and I think there may be a question of spoiler logic? No or reduces spoilers? I don't know the 747. Anyway, they ran off the end of the runway.

The change to rwy 21L didn't help since it's 148'(45m) wide versus 197'(60m). Also the runway is not as well lit and it's ungrooved I believe. I just landed on 21L in BKK about 8 hours ago. It also has lots of rubber on the 21L approach end.

That's how I remember what the FO told me. If it's not exactly correct I apologize. By the way, the FO is back at work, I met him on his first trip back. Very nice chap, as you Brits say.

[Airbubba]

Yep, QF1 at BKK reminds me of another overrun in a rainstorm a few years earlier with a Korean A-300 at Cheju. There was confusion over whether they were landing or going around after a long touchdown, they probably could have done either but like the QF1 prang, not enough room to do both.


_______________________________________

Tuesday, August 16, 1994

(AP) -- The Transportation Ministry on Tuesday blamed the fiery crash of a Korean Air jetliner last week on the pilot and copilot, accusing them of arguing during landing. Pilot Barry Edward Woods shouted "No!" "No!" and "What are you doing? Don't... Wait, man... You're gonna kill us" to his copilot as the plane hurtled toward the runway, cockpit transcripts show.

_________________________________________

Date: 10.08.1994
Time: 11.22 LT
Type: Airbus A.300B4-622R
Operator: Korean Air
Registration: HL7296
C/n: 583
Year built: 1990
Crew: 0 fatalities / 8 on board
Passengers: 0 fatalities / 152 on board
Total: 0 fatalities / 160 on board
Location: Cheju IAP (Korea)
Phase: Landing
Nature: Scheduled Passenger
Flight: Seoul-Kimpo IAP - Cheju IAP (Flightnumber 2033)
Remarks:
The Airbus approached fast and touched down 1773m past the runway threshold. The aircraft couldn't be stopped on the remaining 1227m and overran at a speed of 104kts. After striking the airport wall and a guard post at 30kts, the aircraft caught fire and burst into flames. The approach was flown with slats/flaps at 15/20 degrees due to suspected windshear.

http://aviation-safety.net/database/1994/940810-0.htm

[Lurk R]

crl - I didn't check the pic but if it's the one I was thinking of with the upper slide sitting in the tree, it wasn't actually opened during the evacuation. It was opened by an engineer the following day who didn't realise it was still armed...

[Airbubba]

>>It was opened by an engineer the following day who didn't realise it was still armed...<<

And while he was at it he should have cracked the reversers to make it look a little better for a US$100 million overrun <g>...

[prez]

proof reading after the fact...The wheels touch down and the throttles are at/go to TOGA. The Captain overrides...

sorry for the confusion

[Miles High]

What about this crew discretion thing? Can the capt. apply full reverse if he thinks it's justified - or is there an 'outright' ban (how that would fit in with the capts legal responsibility for safety though I don't know). If qantas do ban it - why and how do they justify it?

We all know how these situations can occur but the bit I'm surprised over is the crew not grabbing a handfull of reverse once they decided they were going to try to stop...

[Feather #3]

Miles,

The discretion was always there; just not used very often and muscle memory faded. Don't forget that this was 18 months ago and things have changed considerably since then!!

As to reverse, for those who know the F/O, ask if there was any swing as they stood on the brakes? Reverse [if that was the case] would simply hasten a departure off the side of the runway.

G'day

[Miles High]

Mmmmm