Video Released from Northwest airways (taxiway collision)

[TobyV]

I don't think that is necessarily true Toby. I've heard of an incident where engineers taxied a 747 on the inboard engine only and found when they needed them they didn't have steering or brakes! Steering & stby brakes are on Syst 1 and normal brakes are on syst 4. Possibly the result was those pictures I posted of the Saudia 747.

In another case somebody was taxiing a Tristar and turning onto the gate the Engineer on the FE's panel thought he would save time and start shutting down the engines, but he shut down the engine that powered the brakes! I've never worked the Tristar so I don't know the systems to validate this tale.

The secret is don't be to proud to use the check lists. It's the first thing they will ask you about come the inquiry.

I'm surprised that the systems are designed in such a way that only a certain engine can drive certain systems - what if you were to lose that engine during a flight? Would that mean that you absolutely have no steering or braking on the ground even though your other engine(s) were still running?

I hear what you say about reading the checklists, but I remember seeing a program on the Air Transat-A330-fuel leak incident and thinking to myself "If only they had used more common sense rather than just applying the procedure as per the literature, they might not have got into the situation" Certainly, in my last job, I was often applying a lot more common sense than just sticking to 'official procedure'. I wasnt too popular in certain quarters for that, but I think I probably got my work done better Weren't any lives at stake though, only people's continued custom

[Kevin]

While I don't want to hijack the thread to a 'what do you mean by an engineer' theme, Toby's point is valid. No-one should be operating the aeroplane without understanding what powers the systems.

If the flight crew inadvertently shut down their one operating hydraulic system because they didn't know no.1 engine powered it, that is most definitely a crew training problem.

If the (licenced?) engineers taxiing the 747 had a similar problem, that questions their competence in that role, too.

My Dad told me an interesting story about one of the RAF Flight Engineers sent to the US to train on the Hecules, when we first bought them in 1966-7. At that time, the US was in the middle of a major ramp-up in Vietnam, and was training a lot of young, first-time aircrew. The RAF, on the other hand, sent its older, more experienced crews, as they were going to form the nucleus of our own C-130 training programme.

When it came to the classroom testing phase of the course, the instructors asked questions about how you would deal with this or that failure. The answers they wanted were commonly 'shut down that system and rely on the backup'. One very experienced RAF FE protested at this and pointed out that in the majority of cases the problem could be worked around by bypassing elements of the systems and retaining at least partial redundancy: he was told "No, sir, that is the wrong answer".

Outside the classroom, the instructors acknowledged the points, but said that they were giving a short, basic course to inexperienced recruits who were going off to war: for them, the safest course was 'shut it down'.

I wonder if this is the situation in some airlines today - both air and ground crew have only a minimal knowledge of the systems they are operating.

Kevin

[VC10]

It doesn't matter if the check list doesn't exactly fit the bill, if the check list appropriate to the situation you use it, other wise they have you by the round objects.

It's like when I am in the A340 run simulator and doing an engine start. The instructor unbeknownst to me programs in a hung start. During the auto start I can see a hung start is happening but I am not supposed to do anything until ECAM throws up the checklist.


With regard to 747 Classic Hydraulics.

Hyd system 4 powers normal braking and alternate brakes are on system 1. Should system 4 fail the brakes automatically change over to system 1. There is a third brake source on system 2 but this has to be manually selected.

If the brake system sees low pressure a 'brake source' light flashes by the Capt's right knee, but is quite low down a could be missed if you are not alert.

The Parking Brake is on System 4 with an accummulater to store hyd pressure. In the case I mentioned above they probably exhausted the accumulator charge during their taxi run so they had no brakes when it came to the 90 degree turn, at which point they found they didn't have steering off system 1 either.

When I am taxiing the first thing I do as soon as I am given taxi clearance is to do a brake & steering check while still at low speed.

Paul.