High speed taxi

[MILSTD]

Hi, just wondering how many of you carry out a high speed taxi check prior to test flying and what systems you test during this sequence.

[Genghis the Engineer]

For light aircraft, I've certainly always carried out fast taxiing before a first flight (of a new type or variant, which de-facto is also all homebuilts) - generally whatever FTI was available for test flying (which is usually minimal in my life!) I'd have also for fast taxi.

Tests would normally cover slow taxi & braking, fast taxi: tracking and braking, accelerate to rotate+ and slow to stop, low hops with basic control checks in ground effect, then landing off that to demonstrate pitch control into the flare. Probably an undercarriage inspection after that before first flight, and confirmation that the pitot-static system was giving something halfway sensible.

I'd assume that more complex aircraft would also encompass checks on the various manual and auto braking systems, although runway length may well preclude hops.

G

[FlightTester]

Exactly as Ghengis describes for us also, plus Ground Lift Dump auto and manual deployments, NWS, and anti-skid runs with one of the mains on the painted centerline (check for any assymetric tendency due to Mu)

[Pilot DAR]

I have, on a few occasions, where an aircraft geometery or controllability problem was suspected, preformed high speed taxi tests, with planned hops, with full flaps extended. Though not an "approved" procedure, the ability to get off the ground at a lower airspeed than "normal" has offered me a glimpse of how it will handle when going faster. As no departure from the runway (or even ground effect) is planned, the requirement for suitable climb performance is not a factor. I have never regretted doing this, and a few times wished I had, when I should have!

I accept the reality that this technique may not be appropriate for many types, but for most single Cessnas, and other similar "low speed" types, I have found it a ressuring basis for the flights to follow.

Pilot DAR

[safetypee]

When you plan to, or might inadvertently ‘hop’, consider any effects of ground/flight switching. A planned short hop and a harsh braked landing in the distance available can be ruined by the engines spooling up to flight idle!

[fanspeed]

We check even thrust increase to TO thrust, NWS (centerline tracking), flight instrument operation, ground spoilers, anti-skid, and thrust reversers.

[MILSTD]

Thanks guys, this will be for a 4 eng turbo prop, which I should have specified, but all your answers were helpful.

Thanks

[411A]

Circa 1981.
411A is due for an L1011 proficiency check (sim unavailable) and the check Captain mentions that we need to do some 'maneuvers' prior, which included a high speed taxi run.
Two high speed taxi runs were completed, nose wheel steering/brakes checked OK, so then off we went for the PC.
We return.
The maintenance folks are standing by for the taxi/test flight report.
The result?
Nil defects.
And this after a 'D' check.
Those familiar with these heavy maintenance checks will understand...nil defects are quite unusual.
This particular middle east airline (SaudiArabian) used (exclusively) Trans World Airlines personnel for their maintenance (then).

Nil squaks?
Par for the course with TWA.
I kid you not...TWA was very very proficient with maintenance procedures.
The absolute best I have seen in forty years of airline flying.

Of course, TWA was absorbed by AA....downhill ever since.:sad:

[V1... Ooops]

I pay a lot of attention to brakes, wheels, and tires after the high speed taxi check. In particular, I like to have the maintenance staff double-check torque on wheels, tire pressures, and have a look at the brakes using an optical thermometer to ensure that all the pucks are operating as they should.

I also like to taxi over a series of objects such as 2 by 4 boards or perhaps sets of chocks that are used for very small aircraft (the 1,500 lb two seat types) just to see what rattles loose in the aircraft - to find out if anyone has left a tool behind, or failed to properly secure a roof panel, etc.

I'm doing first flights of Twin Otters, not Space Shuttles, but still... :)

[TyroPicard]

Many years ago, a BAC 1-11 on a taxy test inadvertently got airborne at 80 kt, with min fuel, AI CB's pulled, low cloudbase... flown by a manager in a suit.
The moral is.. on a taxy test always prepare the a/c for flight, and wear uniform.
TP

[BelArgUSA]

I own a little L-21 ex-army Super Cub, 1953 vintage.
That toy gets airborne at 30-35 mph, one notch of flaps, ground effect.
I fly it often to/from a country airfield, no marked runways or taxyways.
Like helicopters can do, I "taxi" sometimes at 5-10 feet height...
xxx
Get current 3 landings/90 days during taxi. Objections...?
Saves wear on tyres, in any case.
xxx
:}
Happy contrails

[flyboy2]

Always check things out with a fast taxi first.
With a Cessna 185 rebuild, I found undercarraige not tracking the same (alignment was out & thus a/c wouldn't keep straight ), the fuel-pump couldn't deliver enough for full power & thus cut the engine!
Not exactly desireable snags in that type!

[timetime]

I test flew a C206 after a rebuild it had a new wing and many other new parts ....I was cautious and went through all systems and did a high speed taxi check on a very long runway...well I was glad not to be in the air as the machine was rigged badly and needed alot of aileron to keep it level and had a number of faults picked up on the preflight and the runup. It pays to be aware and to plan for the unlikley as it can bit you.