Aircraft breakdown – electrical

So today I want us to focus on some of the common electrical problems that affect aircraft. Now often, it’s pilot error in responding to a problem that causes more difficulty than the problem itself and today we’re going to look at some examples. These reports are quite brief and don’t have a lot of detail but we can get the general idea.

Here’s a report about Cessna 182 which states, ‘Electrical problem. Overran runway returning. Alternator field wire loose. Struck runway light.’ This happened during daytime using VFR. Could the pilot have handled the situation better? We don’t know. But it is a bit strange that with such good visibility the pilot hit the runway light.

The next incident is even more common. An air taxi ‘departed alternators off’, this ended up with the batteries being drained and he had to lower the gear manually, unfortunately they weren’t locked down, and the result was a folded landing.

The next report we’re going to look at shows another alternator problem, this time a failure en route. In this case the pilot was busy trying to sort the alternator out that he landed gear up.

And in our last example while descending from altitude a pilot did ‘a long cruise descent with engines at a very low power output’. He was unaware that the aircraft had generators instead of alternators and that the engine speed on the descent was below the speed required to keep the battery charged.

So let’s have a look at these reports in a bit more detail.

TEXT 26 (2.43 – Track 26)

VOLCANOES

I’ll open this seminar by talking about some of the major volcanic events that have affected aviation over the last thirty years or so.

In the early eighties, several 747s encountered ash in Indonesia. One aircraft lost four engines and descended from 36,000 ft to 12,000 ft before engines were restarted. The engine diverted to Jakarta and landed safely but all four powerplants had to be replaced before it returned to service.

In 1989 a 747-400 with only 900 hours total flying time encountered an ash cloud in Alaska. Although it landed safely, the engines and many systems also had to be repaired or replaced, such as replacement of the aircraft environmental control system, cleaning of the fuel tanks and repair of the hydraulic systems.

In 1991, more than 20 aircraft encountered volcanic ash in the Philippines. This was the largest eruption of the past 50 years and created an enormous plume of ash, making it very difficult to predict where the ash was. Commercial and military operations were affected; one US operator even grounded its aircraft in Manila for several days due to thick ash fall.

An eruption in Mexico affected operations in the region in the late nineties. Although damage was minor in most cases, one flight crew experienced reduced visibility for landing and had to look through the flight deck side windows when taxiing. Mexico City airport was closed for up to 24 hours on several occasions as the volcano continued to erupt.

TEXT 27 (3.05 – Track 27)

COLLISIONS

C1/2/3 = controller 1/2/3

C1	Did you hear what happened at Heathrow yesterday with the A340 and the 747?
C2	Oh, where the Sri Lankan taxied into the BA?
C1	Yep. Caused a few problems, but there wasn’t too much damage, no injuries.
C3	I heard that a bunch of passengers refused to fly on the 340 today because the wing tip was missing.
C2	Eh? I thought it was the Sri Lankan airbus’s right leading edge that struck the winglet on the BA, not the other way around.
C1	That’s right. The BA was stationary and the Sri Lankan was passing to the left.
C3	Couldn’t the 340 fly easily without a wingtip?
C1	Yeah, I thought that was possible.
C3	Yes, it is as far as I know. An A380 flew after one of its tips clipped the hangar gate at Bangkok, but they removed both wingtips and the aircraft flew OK.
C2	Hmm I’m not so sure. Are wingtips on the CDL?
C1	No, they’re not, but I’m pretty sure that CDLs don’t cover taking off equipment damaged in accidents.
C2	I wonder who was out of position yesterday? The taxi and parking lines are supposed to guarantee clearance.
C3	Not necessarily. They’ve recently repaved the holding point where it happened, and the airport documents say ‘Wingtip clearance not assured, take care when passing’.
C1	Yeah,, at Seattle tower once, a China Airlines F340 was taxiing into gate and as it taxied on the taxiway centerline, the right winglet struck an American MD80’s horizontal stabilizer, even though it was parked.
C2	And did it fly afterwards?
C1	Yup, it left a few hours later, one winglet short.

TEXT 28 (3.08 – Track 28)

AIRDROP

R = reporter, CW = Colonel Wang

R

A terrible earthquake has cut off all land routes into Xiang province. The only possible way to get supplies into the area was by making an airdrop. A special reconnaissance force was assembled and sent into the area most affected by the quake. Fifteen parachutists were dropped from a record breaking 4,000 m. To add to the difficulty they were forced to land without any help from ground crew and there were not any specific landmarks. Once the parachutists had landed they provided information to the air force about where to drop supplies. Five tons of aid materials including food and water were delivered. The supplies were dropped by an EU76 aircraft from 5,800 m. This is quite an unusual operation for this type of aircraft. Normally the air drops take place at about 600 m above sea level. But even though the terrain was so difficult and the weather conditions so poor, the air force were able to complete their mission. Colonel Wang, the leader of the reconnaissance group, explained the difficulties the reconnaissance group had to deal with.

CW

Of course it was a very difficult and dangerous situation, but we had a job to do. We had to make sure that all the food was dropped in the right places and not scattered around the countryside. Because we were in the middle of the mountains and the visibility was so bad it was hard to find the goods. But because of the dedication and skill of my team we were able to locate and distribute the much needed supplies.

TEXT 29 (3.11 – Track 29)

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