Modern Cockpits Rest On Pioneers’ Shoulders, Part 1

It’s good for any endeavor to look back at its origins, thus attempting to ensure modern participants feel the passion of the founders.

We have a right to be proud when we consider the occupation in which we participate. Thousands of miles are covered, carrying hundreds of passengers often over multiple weather systems, on flights of up to 17 hours.

This is done on such a routine basis that, to our passengers, it is considered no more of an accomplishment than the taxi ride to the airport. In fact, for them, the flights are usually a lot more pleasant than the cab ride once the chocks are pulled and the push back has been accomplished.

Navigation and instrumentation are so accurate and dependable that clearances of these flights are received, acknowledged and loaded into navigation systems with the tap of a button. Climbing out of the New York area, flights are often cleared direct to the oceanic entry point, many miles down range, before they even reach their cruising altitude. Those flights can end with approaches that don’t present the runway environment until they are rolling on it.

Over the decades, we’ve learned the value of not only extra crew members on extremely long flights, but extra crews. We’ve learned the fact that even two days off does not justify operating more than 8-10 hours without some sort of relief or break. We’ve learned to work as a directed team, taking input from all crewmembers concerned with the task at hand.

Who paid the price for our expertise? Whose shoulders are we standing on each time the wheels come up?

Pan American Flight 151, a Lockheed L-049 Constellation with 31 passengers and nine crew on board, departed Johannesburg at 0825Z in the morning, June 22, 1951, and crashed making an instrument approach into Monrovia, Liberia, at approximately 0325Z, 19 hr. later in the night. This after making a stop in Leopoldville (now Kinshasa, Democratic Republic of Congo), and then a further stop in Accra, Ghana, where an engine problem was worked. 

They had pressed on, after the repair, intending to make yet one more stop in Monrovia before resting in Dakar, Senegal.

Although there were seven flight crewmembers, only two of them were qualified to make instrument approaches and landings. Others included a second officer navigator, a third and fourth officer, two flight engineers and two cabin crew.

In the middle of the night, we join the flight enroute from Accra to Monrovia, using Accra and Dakar as alternates with enough fuel to return to either of those fields after attempting a landing at Monrovia. There was no pressure to get on the ground due to fuel and the flight proceeded normally and reported over Cape Palmas. There was no navigational radio facility at Cape Palmas, so that position must have been determined by other means, most likely dead reckoning, as cloud cover would have prevented the navigator from taking a shot.  

The course from Cape Palmas to Roberts International Airport, also called Robertsfield, in Monrovia is nearly the same as one of the “legs,” the approach they would need to use. This should have made it easy to establish on the approach. Nevertheless, the radio signals were not strong enough to allow reception further than 50 mi.

Flight Never Reaches Destination

A half hour after the report over Cape Palmas, the flight was cleared to begin descent to 3000 ft. and told to make further instrument descent via the approach procedures. Roberts Field reported the weather as 1000 ft. overcast, 3 mi. in light rain with light and variable winds. 

Ground personnel continued listening for the arrival of the flight, but the aircraft’s engine noise was never heard in the otherwise still night. The ETA of 0246 came and went without sign of the flight. This led to the conclusion that the flight never reached the local area of Roberts field.

The flight was 9 min. past its ETA when it attempted contact with Robertsfield on VHF, at 118.1 The tower responded, repeating the call three times and, when there was no reply, requested that the flight try contact on high-frequency (HF) radio.

Nineteen minutes past its ETA at 0305, the flight again contacted Roberts on HF, reporting that the Dakar beacon appeared to be overriding the Roberts beacon. The aircrew said they would speak to Dakar about getting its beacon turned off and “be back in 15 minutes.” Robertsfield acknowledged the call and advised the flight they too would call Dakar and request they turn their beacon off.

However, due to incoming traffic, the Dakar beacon was not turned off until 0410 in the morning

At 0315, the flight again called Robertsfield. The weather was transmitted but never acknowledged. This was the last contact with the flight.  It is estimated it crashed at 0325.

By the directions the flight was observed, the aircraft apparently was flying courses that would have been consistent with the instrument approach into the airfield but had let down and crashed 54 mi. northeast, instead of southwest, of Roberts International, having completely bypassed the field.

The tower continued trying to reach the flight until 0410. Emergency procedures were activated, and a dispatch sent at 0515 to all stations in the company announcing the overdue aircraft. An aerial search would begin at daylight.

That search produced no results.  The following day a messenger arrived by foot from the village of Sanoyie, Liberia, reporting that the crash had occurred near his village and there were no survivors.

In the vicinity of the crash, the flight was east of a line of storms but the cloud bases were probably down to near the hill tops. Witnesses who heard the aircraft flying northerly and then saw it flying low on a southerly heading just prior to the crash, stated that the night was dark but no rain was falling. There had been heavy rain earlier in the evening.

Turbulence does not appear to have been likely in the immediate vicinity of the crash area and the winds were light.

All navaids were in proper working order at the time of the crash. The weather at both alternates was above minimums and, as noted, the flight had plenty of fuel to easily reach either of them at the time it impacted the ground.

“In the absence of no indications of mechanical trouble, there is no logical explanation for the captain’s action in descending without having positive knowledge of the flight’s position,” states the U.S. Civil Aeronautics Board accident investigation report. “It must be concluded, therefore, that he made his descent with the mistaken belief the flight’s position was such that he could safely descend.”

But the flight crew was northeast of the station instead of southwest over the ocean. Did the pilots think they heard the fan markers or had just missed the cone of confusion to show they were over the station?

The pilots of Pan American Flight 151 were as ready and competent as training could make them at that time, but they didn’t have the technology and tools that guide pilots today, in Part 2 of this article.