RADIO / More Bigfoot than fly: Dermot Clinch reviews Radio 4's new documentary series, The Airport

Hospitals, railway stations, schools: the service industries have always been a favourite with fly-on-the-wall documentaries. All those edifices where an expectant citizenry comes into close contact with the people it pays to serve it are an irresistible attraction. Last week - having already done teachers, doctors and surgeons - Radio 4 descended for a new eight-part series on The Airport.

The venue ought to be a good one. In theory, at least, an airport - in this case Birmingham International - is a bottomless repository of drama, laughter and tears, where staff and public alike can be candidly observed going about their business. Unfortunately, radio isn't easy on the fly- on-the-wall drama. Television can move around quietly and be intelligible as it lets real things go on excitedly all about it. More than a few seconds of footsteps drumming mysteriously down the corridors of Birmingham International, however, and listeners are demanding an explanation. Without ruining the illusion, the producer has to find a way of saying what all the puffing's in aid of.

So far, The Airport's answer has been to reach for the telephone. Where else, after all, are people so often found explaining things at length and in such detail? Every other conversation of the first programme seemed to involve a prefatory buzz or click. One moment it was security ringing up from Lounge A to inform us that a man was getting out of hand down there. The next, it was Steve from check-in, calling about the problem with BA business- class lunches. Thomson Holidays rang about the group who'd forgotten their passports. The 'apron' - whoever they are - phoned in about I forget what. In this airport no one would ever get lost: we were being told where we were and what was going on all the time.

Drama lost out to intelligibility as a result. Take the single truly dramatic incident of the programme: brrr, click went the phone. 'Hello, press office?' said a voice. 'Just to let you know there's a bomb on board the in-bound Frankfurt . . .' said another. At this point we should have heard bells ringing, fire engines honking, sweat pouring down furrowed brows. Instead we had a press officer on the phone. 'So that's Flight Ell-Aitch Four-Oh-Five-Oh from Frankfurt,' she repeated calmly - and for all the world she might have been talking to her mum.

Generally, though, you could tell the odds had been against the producers. It was a dearth of incident that caused the low excitement count of this first programme. At one point, a trip to Chicago had looked promising, but it turned out disappointingly ('the bricks to make this agreement haven't been put together yet,' as the airport's Deputy MD said). A fight nearly broke out in Lounge A, but didn't. And the catering problem never quite delivered either: 'OK,' a steward was heard telling a flight attendant, 'So, that's three on aisle 8, A C and F. Also 10 F, 7 A and B' It was hardly going to set pulses racing.

And yet, somehow, The Airport kept you with it and it would be unjust to say it doesn't look promising. The characters are becoming familiar. We know where we're going. And it's lightly put together, with each individual narrative well defined and shifting neatly into the next. So far we've only had reports of drama, it's true. But, so long as it steers clear of the phone, the next episode might just give us a taste of the real thing.

The Airport: R4, 10am Weds, repeated 7.30pm Sun