Nose wheel brakes

[Terry McCassey]

I was explaining to a young Airbus F/O recently the reason for the MEL requirement to leave the gear extended for 2 minutes after take-off with a main gear brake unit de-activated. With this requirement in mind, any-one tell me if the DH Trident had nose wheel brakes ? Terry

[bizdev]

No the Trident did not have nose wheel brakes - it did have cooling fans built into the main gear axles though. The only Aircraft I ever came across (Civil) with nose wheel braking was the B727.

[dixi188]

I wonder why your Airbus requires 2 mins. of gear down with brake de-activated.
Our A300s only need 1 min. and we often have rotate speeds around 170kts.

Just curious.

Also Boeing 727 is the only A/C I've come accross with nose wheel brakes, and then only on short field mod A/C.
A quick google also talks of Convair 880 & 990 having nose wheel brakes. There may be others.

[Nipper1011]

I believe that the short field mod for the 737 also includes nose wheel brakes. Maersk Air used to have a -500 modified for Vagar.

[pjac]

The Convair 880 had nose wheel brakes

[26er]

I believe the BAC 1-11/475 was intended to have nosewheel braking to go with its fat lower pressure mainwheels for operation from rough airstrips. Fawcett used a couple in Peru but the one I flew, GAZUK, brought from them by Mediterrean Express did not.

[By George]

The 727 had nose wheel brakes, on three different models that I flew and never heard of them refered to as a 'short field mod'. The penalty for them being U/S was 2000kg If my memory is correct.

[innuendo]

Air Canada's B-727s had nosewheel brakes but eventually they were de-activated, (removed?).
The N/W brakes did not actually come into operation and apply any braking unless the pedals were flat to the floor, or close to it, I can't remember the exact threshold where they came on.
In everyday service full braking very rarely happened and the N/W brakes were never really required for performance purposes, so they were seen as a weight and maintenance cost that was not justified.

[MarkerInbound]

The 727 nose brakes are available when both brake pedals are depressed approximately 50% of their travel, anti-skid is ON and the aircraft is taxiing 15 knots or more.

There are a few 727s that still have their nose brakes, mainly VIP planes that would have needed ballast weight to move the CG forward due to the cabin layout.

[twochai]

IIRC we tested nosewheel brakes during the Dash 7 development program, in an attempt to improve RTO performance and gain payload on limiting runways. My recollection is that they did not produce significant incremental decel and were abandoned as not being worth the trouble.

[Terry McCassey]

Thanks all - The B727's I worked with the nose brakes were -200's with the JT8D-17AR engines, 88 tonnes MTOW I think, originally ordered for a private customer . . .

[CV880]

Convair 880 (and presumably 990) nose wheel brakes only operated when brake pedals were almost at maximum deflection. I think they also operated as spin down brakes on retraction. Never wore out.
I recall a CV880 incident in Japan where a malfunction locked the nosewheel brakes on touchdown resulting in extremely square nosewheels, a damaged nose gear axle and a gouge in the runway.

[pjac]

The criteria for nose-wheel brake operation on the CV880 was operating hydraulic pressure sensed in the down line, nose wheel down & locked, nose wheel within 7 degrees of centre and both pedals depressed.

[ICT_SLB]

26er said:
"I believe the BAC 1-11/475 was intended to have nosewheel braking to go with its fat lower pressure mainwheels for operation from rough airstrips. Fawcett used a couple in Peru but the one I flew, GAZUK, brought from them by Mediterrean Express did not."

26,
AFAIK none of the 475's had nosewheel brakes - at least I don't think they were fitted when they left Hurn. The only 1-11 variant I know to have an extreme braking requirement was the Type 670, which was intended to get into one of the Japanese offshore islands even in a tropical downpour (think 475 with normal tyres). They modified G-ASYD with different manufacturer's braking & anti-skid systems on pallets in the cabin but, while I did some of the electrical work, I don't know if nosewheel brakes were installed for that variant either.

[M2dude]

Concorde had a nose wheel brake. It was fitted to the L/H wheel (common axle) and was based on a Ford automotive unit!!

[DH106]

Yes - but I believe Concorde's nosewheel brake was a puny unit design purely to stop wheel rotation prior to retraction - this presumably because the nose leg was so long that gyroscopic forces were considerable...

[27mm]

Interesting thread - IIRC, there are some CIS military jets with nosewheel brakes too....

[M2dude]

DH106, you are correct. (Although I don't think that it is Kosher, mentioning Concorde and puny in the same breath := :)).

[DH106]

M2dude - absolutely :eek:, my bad ! :}